ACRONYM III: Radial Velocities for 336 Candidate Young Low-Mass Stars in the Solar Neighborhood, Including 78 Newly Confirmed Young Moving Group Members

TL;DR

This study provides radial velocities and youth diagnostics for 336 nearby low-mass stars, confirming 78 as members of young moving groups, identifying new members, and refining the ages of stellar associations using Gaia data.

Contribution

It offers the first comprehensive kinematic and youth assessment for a large sample of candidate young low-mass stars, including new group members and refined ages of associations.

Findings

78 stars confirmed as members of 10 young moving groups

15 new or reclassified group members identified

Carina association found to be younger (~22 Myr) than previously thought

Abstract

Young, low-mass stars in the solar neighborhood are vital for completing the mass function for nearby, young coeval groups, establishing a more complete census for evolutionary studies, and providing targets for direct-imaging exoplanet and/or disk studies. We present properties derived from high-resolution optical spectra for 336 candidate young nearby, low-mass stars. These include measurements of radial velocities and age diagnostics such as H$\alpha$ and Li $\lambda$6707 equivalent widths. Combining our radial velocities with astrometry from Gaia DR2, we provide full 3D kinematics for the entire sample. We combine the measured spectroscopic youth information with additional age diagnostics (e.g., X-ray and UV fluxes, CMD positions) and kinematics to evaluate potential membership in nearby, young moving groups and associations. We identify 78 objects in our sample as bonafide members of 10 different moving groups, 15 of which are completely new members or have had their group membership reassigned. We also reject 44 previously proposed candidate moving group members. Furthermore, we have newly identified or confirmed the youth of numerous additional stars that do not belong to any currently known group, and find 69 co-moving systems using Gaia DR2 astrometry. We also find evidence that the Carina association is younger than previously thought, with an age similar to the $\beta$ Pictoris moving group ($\sim$22 Myr).

Figures

Tables

Table 1. Table 1: Observations Summary

2MASS	Other	Telescope/	Obs. Date	RV	SB?
Designation	Name	Instrument	(UT)	(km s-1)
00153670$-$2946003	GJ 3017	Magellan/MIKE	2009 Dec 31	0.61$\pm$1.31	…
00213729$-$4605331	GJ 3029	Magellan/MIKE	2009 Jun 06	-19.32$\pm$0.12	…
00254902$+$4501315	[FS2003] 0016	Keck/HIRES	2012 Dec 28	6.30$\pm$0.32	…
00354412$-$0541102	LP 645-53	Magellan/MIKE	2009 Jun 07	-15.63$\pm$0.17	…
00501079$-$0337532	…	Magellan/MIKE	2010 Jan 01	0.27$\pm$1.24	…
00503319$+$2449009	GJ 3061	DuPont/Echelle	2009 Aug 21	5.42$\pm$0.38	…
00503319$+$2449009	GJ 3061	Magellan/MIKE	2009 Dec 31	7.44$\pm$1.24	…
00503319$+$2449009	GJ 3061	Magellan/MIKE	2009 Dec 31	7.53$\pm$1.58	…
00503319$+$2449009	GJ 3060	Magellan/MIKE	2009 Dec 31	5.60$\pm$0.79	…
00503319$+$2449009	GJ 3060	Magellan/MIKE	2009 Dec 31	5.64$\pm$0.87	…
00560596$+$4153282	…	Keck/HIRES	2013 Oct 24	-33.12$\pm$0.17	…
01031408$+$2005523	GJ 1026 A	DuPont/Echelle	2009 Aug 21	21.51$\pm$0.38	…
01031408$+$2005523	GJ 1026 B	DuPont/Echelle	2009 Aug 21	21.87$\pm$0.41	SB1
01031408$+$2005523	GJ 1026 B	Magellan/MIKE	2009 Dec 31	20.11$\pm$0.92	SB1
01031408$+$2005523	GJ 1026 B	Magellan/MIKE	2009 Dec 31	21.53$\pm$0.39	SB1
01050677$+$2815049	1RXS J010506.0+281505	Keck/HIRES	2013 Oct 24	3.85$\pm$0.39	…
01090150$-$5100494	DG Phe	Magellan/MIKE	2009 Jun 08	-1.15$\pm$0.81	…
01112542$+$1526214	GJ 3076	Keck/HIRES	2012 Dec 28	2.84$\pm$0.12	…
01132401$-$2254077	GJ 1033	DuPont/Echelle	2013 Dec 19	-0.13$\pm$0.80	…
01132958$-$0738088	StKM 1-124	DuPont/Echelle	2013 Dec 18	115.97$\pm$2.37	SB1
01205998$-$2408520	BPS CS 29514-0033	Magellan/MIKE	2009 Jun 07	3.48$\pm$5.98	…
01210504$-$0402082	G 271-42	Magellan/MIKE	2010 Jan 01	9.30$\pm$1.83	…
01244246$-$1540454	G 272-13	DuPont/Echelle	2013 Dec 18	18.09$\pm$0.60	…
01245068$-$3844389	SERC 296A	Magellan/MIKE	2011 Jun 14	16.20$\pm$0.51	…
01302034$-$2557105	GSC 06426-01758	Magellan/MIKE	2009 Jun 07	13.56$\pm$0.24	…
01335800$-$1738235	LP 768-113	Magellan/MIKE	2010 Jan 01	5.87$\pm$0.28	…
01345037$-$0254397	…	Magellan/MIKE	2010 Jan 01	-11.27$\pm$1.46	…
01452133$-$3957204	CD-40 436	DuPont/Echelle	2013 Dec 18	21.06$\pm$0.59	…
01484087$-$4830519	GSC 08044-00859	Magellan/MIKE	2010 Jan 01	21.32$\pm$0.31	…
01511997$+$1324525	[ZEH2003] RX J0151.3+1324 3	Magellan/MIKE	2010 Jan 01	25.96$\pm$0.42	…
01564714$-$0021127	GSC 04686-00596	Magellan/MIKE	2010 Jan 01	3.43$\pm$1.33	…
02130073$+$1803460	LP 409-52	DuPont/Echelle	2009 Aug 21	2.68$\pm$0.43	SB1
02130073$+$1803460	LP 409-52	Magellan/MIKE	2009 Dec 31	2.97$\pm$0.61	SB1
02133021$-$4654505	WISE J021330.24-465450.3	Magellan/MIKE	2010 Jan 01	10.33$\pm$1.02	…
02135155$-$4129304	CD-42 759	DuPont/Echelle	2013 Dec 18	8.33$\pm$1.09	…
02135155$-$4129304	CD-42 759	DuPont/Echelle	2013 Dec 18	10.28$\pm$1.93	…
02165488$-$2322133	1RXS J021655.0-232216	Magellan/MIKE	2010 Jan 01	3.81$\pm$2.53	…
02202235$-$0808253	LP 650-215	Keck/HIRES	2013 Oct 24	3.37$\pm$1.07	…
02291365$-$1009419	…	Magellan/MIKE	2010 Jan 01	12.94$\pm$0.40	…
02344773$-$2222451	…	Magellan/MIKE	2010 Jan 01	8.36$\pm$1.70	…
02371574$-$2222590	…	Magellan/MIKE	2010 Jan 01	3.54$\pm$0.44	…
02374615$-$0705480	LHS 1427	Keck/HIRES	2013 Oct 24	-8.01$\pm$0.08	…
02390078$-$1937040	…	Magellan/MIKE	2010 Jan 01	23.41$\pm$0.69	…
02411909$-$5725185	GSC 08494-00369	Magellan/MIKE	2010 Jan 01	7.03$\pm$0.43	…
02411909$-$5725185	GSC 08494-00369	Magellan/MIKE	2010 Jan 01	8.68$\pm$0.60	…
02442137$+$1057411	MCC 401	DuPont/Echelle	2013 Dec 20	5.60$\pm$1.09	…
02445715$-$4407313	…	Magellan/MIKE	2010 Jan 01	16.79$\pm$0.67	…
02461477$-$0459182	GJ 3180	Magellan/MIKE	2009 Jun 07	35.00$\pm$0.22	…
02490228$-$1029220	UCAC4 398-003401	Magellan/MIKE	2010 Jan 01	16.85$\pm$0.43	…
02492136$-$4416063	…	Magellan/MIKE	2010 Jan 01	29.06$\pm$0.31	…
02511150$-$4753077	GSC 08054-00859	DuPont/Echelle	2013 Dec 19	-15.11$\pm$0.88	…
02523096$-$1548357	…	Keck/HIRES	2012 Dec 28	73.68$\pm$0.59	…
02535980$+$3206373	…	Keck/HIRES	2006 Aug 12	-36.26$\pm$0.81	SB1
02535980$+$3206373	…	Keck/HIRES	2012 Dec 28	-34.64$\pm$0.17	SB1
02545247$-$0709255	…	Keck/HIRES	2012 Dec 28	25.11$\pm$0.18	SB2
02560388$-$0036332	LP 591-156	DuPont/Echelle	2009 Aug 21	46.29$\pm$0.38	SB1
02560388$-$0036332	LP 591-156	Magellan/MIKE	2009 Dec 31	46.04$\pm$0.40	SB1
03033668$-$2535329	CD-26 1122	Magellan/MIKE	2012 Jan 16	16.94$\pm$0.71	…
03051118$-$3405239	LP 942-107	DuPont/Echelle	2013 Dec 18	24.32$\pm$0.64	…

Table 2. Table 2: Sample Properties

Column Label	Description
2MASS	2MASS Designation
SpT	Spectral Type
SpT_ref	Reference for SpT
Dist	Distance from Gaia DR2
e_Dist	Error in distance
$\mu$α	Proper motion in right ascension
e_$\mu$α	Error in $\mu$α
$\mu$δ	Proper motion in declination
e_$\mu$δ	Error in $\mu$δ
ast_note	Astrometry note
RV	Radial velocity
e_RV	Error in radial velocity
X	X position
e_X	Error in X
Y	Y position
e_Y	Error in Y
Z	Z position
e_Z	Error in Z
U	U velocity
e_U	Error in U
V	V velocity
e_V	Error in V
W	W velocity
e_W	Error in W
Gmag	Gaia G magnitude
e_Gmag	Error in Gmag
RPmag	Gaia GRP magnitude
e_RPmag	Error in RPmag
BPmag	Gaia GBP magnitude
e_BPmag	Error in BPmag
Jmag	2MASS J magnitude
e_Jmag	Error in Jmag
Hmag	2MASS H magnitude
e_Hmag	Error in Hmag
Kmag	2MASS KS magnitude
e_Kmag	Error in Kmag
Li	Lithium $\lambda$6707 equivalent width
H$\alpha$	H$\alpha$ equivalent width
log $L_X$	X-ray luminosity
e_log $L_X$	Error in log $L_X$
FUV	GALEX FUV magnitude
e_FUV	Error in FUV
$f_{\mathrm{FUV}}$/$f_J$	FUV to J flux ratio
NUV	GALEX NUV magnitude
e_NUV	Error in NUV
$f_{\mathrm{NUV}}$/$f_J$	NUV to J flux ratio

Table 3. Table 3: RV Comparisons

2MASS	RV${}_{\mathrm{This}\mathrm{Work}}$	RVLit	Ref
Name	(km s-1)	(km s-1)
00153670$-$2946003	0.61$\pm$1.31	63.4	7
…	0.61$\pm$1.31	0.02$\pm$4.84	61
00213729$-$4605331	-19.32$\pm$0.12	49.2	7
…	-19.32$\pm$0.12	-30.70$\pm$0.32	24
00501079$-$0337532	0.27$\pm$1.24	5.16$\pm$2.98	61
…	0.27$\pm$1.24	5.95$\pm$4.46	64
00503319$+$2449009	5.69$\pm$0.35	9.2	6
…	5.69$\pm$0.35	6.2	15
…	5.69$\pm$0.35	6.00$\pm$1.10	23
…	5.69$\pm$0.35	6.40$\pm$11.50	22
…	5.69$\pm$0.35	5.60$\pm$1.00	16

Table 4. Table 4: Co-Moving Systems

Sys.	Comp.	Gaia R.A.	Gaia Dec.	plx	$\mu$δ	$\mu$α	Separation	Separation
No.	No.	($°$)	($°$)	(mas)	(mas yr-1)	(mas yr-1)	(″)	(AU)
1	1.1	6.45495504961	45.025376915	15.8615$\pm$0.0801	102.891$\pm$0.08	-9.526$\pm$0.036	…	…
…	1.2	6.45743133884	45.0269135029	16.0416$\pm$0.1055	102.809$\pm$0.111	-8.653$\pm$0.05	8.4	523
2	2.1	14.024420588	41.891185381	16.331$\pm$0.0607	-78.979$\pm$0.103	4.156$\pm$0.105	…	…
…	2.2	14.019747768	41.8900123923	15.9529$\pm$0.0489	-83.873$\pm$0.066	3.93$\pm$0.081	13.2	828
3	3.1	15.8126716282	20.0984581507	62.1$\pm$0.2033	677.548$\pm$0.436	26.765$\pm$0.296	…	…
…	3.2	15.812059101	20.0980757415	62.627$\pm$0.0425	672.249$\pm$0.079	50.851$\pm$0.067	2.5	40
4	4.1	18.3735917791	-7.63608776673	15.3648$\pm$0.0516	74.651$\pm$0.075	-68.292$\pm$0.06	…	…
…	4.2	18.3729635322	-7.63663544495	15.6057$\pm$0.1904	70.301$\pm$0.259	-66.398$\pm$0.207	3.0	191
5	5.1	20.2718431581	-4.03570030568	11.1213$\pm$0.0475	169.306$\pm$0.085	-8.59$\pm$0.053	…	…
…	5.2	20.2727145599	-4.03661690337	10.9178$\pm$0.0791	171.761$\pm$0.148	-8.094$\pm$0.074	4.5	417
6	6.1	27.1710820305	-48.5146518446	25.5403$\pm$0.0235	110.899$\pm$0.037	-53.968$\pm$0.036	…	…
…	6.2	27.1995848064	-48.5212175903	25.6167$\pm$0.0416	110.54$\pm$0.058	-53.667$\pm$0.061	72.0	2809
7	7.1	33.4650594831	-41.491991267	11.9977$\pm$0.0246	56.572$\pm$0.03	-18.784$\pm$0.035	…	…
…	7.2	33.4655848276	-41.4911563705	11.9931$\pm$0.0188	54.584$\pm$0.023	-19.257$\pm$0.027	3.3	277
8	8.1	34.2288032428	-23.3703726789	13.7216$\pm$0.0778	26.234$\pm$0.146	1.122$\pm$0.14	…	…
…	8.2	34.2278548085	-23.369533735	13.6387$\pm$0.0468	21.64$\pm$0.09	-0.189$\pm$0.083	4.4	319
9	9.1	37.306737751	-10.1615812986	16.3434$\pm$0.076	-34.882$\pm$0.106	-18.49$\pm$0.105	…	…
…	9.2	37.3065913493	-10.1620032446	16.7055$\pm$0.0835	-25.918$\pm$0.131	-10.12$\pm$0.117	1.6	96
10	10.1	40.3298322728	-57.4217128511	11.3641$\pm$0.0451	14.729$\pm$0.072	29.64$\pm$0.081	…	…
…	10.2	40.3290993909	-57.4215856312	11.6443$\pm$0.0783	17.917$\pm$0.103	30.519$\pm$0.132	1.5	128
11	11.1	41.0893497836	10.9611708044	20.5066$\pm$0.1372	67.385$\pm$0.285	-56.036$\pm$0.242	…	…
…	11.2	41.0950166414	10.9594993429	21.3227$\pm$0.0865	73.847$\pm$0.178	-58.413$\pm$0.146	20.9	981
12	12.1	43.718796959	-7.15734233716	21.5234$\pm$0.0666	38.938$\pm$0.149	-55.285$\pm$0.13	…	…
…	12.2	43.7176761993	-7.15704206394	21.3807$\pm$0.0896	34.261$\pm$0.194	-64.692$\pm$0.165	4.1	194
13	13.1	51.0280110852	23.7845173999	48.2954$\pm$0.0494	215.05$\pm$0.1	-120.236$\pm$0.07	…	…
…	13.2	51.0277404632	23.7851922099	48.0921$\pm$0.0617	200.851$\pm$0.127	-114.325$\pm$0.089	2.6	54
…	13.3	51.0545524391	23.7714861393	48.4516$\pm$0.0677	205.518$\pm$0.104	-110.346$\pm$0.08	99.2	2048
14	14.1	53.0148285759	-51.6652419697	13.0328$\pm$0.0228	50.184$\pm$0.039	7.261$\pm$0.049	…	…
…	14.2	53.016112676	-51.6656193486	13.0197$\pm$0.0449	50.644$\pm$0.079	6.542$\pm$0.097	3.2	244
15	15.1	54.9491321525	33.4751835323	25.465$\pm$0.119	-38.631$\pm$0.135	-3.727$\pm$0.109	…	…
…	15.2	54.9538270286	33.4734135346	25.4853$\pm$0.0849	-35.974$\pm$0.111	-2.512$\pm$0.083	15.5	607
16	16.1	64.4876758851	-38.4513485042	25.5609$\pm$0.5218	-95.676$\pm$1.166	-64.997$\pm$1.007	…	…
…	16.2	64.4923466117	-38.4293196842	26.5906$\pm$0.0688	-100.751$\pm$0.111	-67.663$\pm$0.142	80.4	3023
17	17.1	71.0441624381	-70.323716455	47.5062$\pm$0.0253	-120.466$\pm$0.046	-65.845$\pm$0.055	…	…
…	17.2	71.0450943035	-70.3243619533	47.4314$\pm$0.0646	-102.042$\pm$0.149	-46.054$\pm$0.195	2.6	54
18	18.1	77.5207049404	-23.6709966491	17.3479$\pm$0.0408	38.099$\pm$0.06	-9.074$\pm$0.062	…	…
…	18.2	77.5202711962	-23.6706992996	17.275$\pm$0.0487	36.988$\pm$0.073	-13.443$\pm$0.071	1.8	103
19	19.1	78.2567403265	-70.4607095853	30.9077$\pm$0.0738	107.157$\pm$0.157	234.762$\pm$0.191	…	…
…	19.2	78.257702683	-70.4603692812	31.0644$\pm$0.0557	119.442$\pm$0.125	223.431$\pm$0.113	1.7	54
20	20.1	78.6142599655	-15.247715066	13.145$\pm$0.0414	34.552$\pm$0.06	-15.176$\pm$0.07	…	…
…	20.2	78.6134888585	-15.2477399307	13.1076$\pm$0.0653	35.722$\pm$0.096	-13.416$\pm$0.109	2.7	204
…	20.3	78.6201038834	-15.2485743739	13.1976$\pm$0.0467	33.49$\pm$0.068	-15.008$\pm$0.079	20.5	1556
21	21.1	79.9874389463	-11.4123560204	14.1972$\pm$0.0438	27.299$\pm$0.07	-21.627$\pm$0.069	…	…
…	21.2	79.982721039	-11.4159132296	14.4424$\pm$0.0627	26.531$\pm$0.097	-22.415$\pm$0.093	21.0	1454
22	22.1	87.5469822497	9.66803304279	39.7713$\pm$0.182	257.061$\pm$0.275	239.913$\pm$0.21	…	…
…	22.2	87.55008623	9.66473068132	39.6816$\pm$0.1052	263.405$\pm$0.142	239.802$\pm$0.116	16.2	408
23	23.1	90.0958524601	-44.0225800557	14.4695$\pm$0.0525	25.378$\pm$0.086	15.806$\pm$0.097	…	…
…	23.2	90.0965597837	-44.0227244432	14.4132$\pm$0.0538	23.151$\pm$0.087	15.075$\pm$0.113	1.9	132
24	24.1	91.5725680245	-27.9012654117	27.9688$\pm$0.0376	-10.53$\pm$0.062	32.007$\pm$0.078	…	…
…	24.2	91.5691507809	-27.9056805417	27.9831$\pm$0.0294	-16.297$\pm$0.039	34.359$\pm$0.045	19.3	688
25	25.1	93.4239587636	-28.2545771594	24.2785$\pm$0.31	27.198$\pm$0.576	86.668$\pm$0.516	…	…
…	25.2	93.4239732732	-28.2542821755	23.3908$\pm$0.2541	31.168$\pm$0.488	90.478$\pm$0.491	1.1	45
…	25.3	93.506342479	-28.2611592687	23.606$\pm$0.0791	27.352$\pm$0.11	90.76$\pm$0.128	262.3	11112
…	25.4	93.5068390109	-28.2606529165	23.8732$\pm$0.0426	26.88$\pm$0.059	92.051$\pm$0.069	263.7	11047
26	26.1	93.4385067821	-23.8614582851	59.7617$\pm$0.0243	-47.733$\pm$0.026	110.9$\pm$0.042	…	…
…	26.2	93.4464230422	-23.9064161051	60.0064$\pm$0.0432	-31.043$\pm$0.05	110.803$\pm$0.07	163.9	2732
27	27.1	98.8201005228	-19.1919537555	8.2974$\pm$0.0336	-10.615$\pm$0.05	-28.548$\pm$0.064	…	…
…	27.2	98.8200891154	-19.1923472134	8.2239$\pm$0.0418	-8.326$\pm$0.067	-26.52$\pm$0.066	1.4	172
28	28.1	99.5012976895	-40.9331925133	25.9455$\pm$0.0339	-0.901$\pm$0.072	100.528$\pm$0.064	…	…
…	28.2	99.4934539826	-40.9322052962	25.9428$\pm$0.0551	1.569$\pm$0.106	102.576$\pm$0.101	21.6	834
29	29.1	107.99652442	-35.1711642829	27.0922$\pm$0.0767	-18.251$\pm$0.197	-59.482$\pm$0.158	…	…
…	29.2	107.996305062	-35.1713921997	27.3922$\pm$0.5966	-34.898$\pm$0.937	-50.518$\pm$1.01	1.0	38
30	30.1	122.46684401	3.01931596993	10.2325$\pm$0.0356	-15.159$\pm$0.064	-39.245$\pm$0.04	…	…
…	30.2	122.467210115	3.01985424758	10.2347$\pm$0.0379	-17.262$\pm$0.065	-39.799$\pm$0.042	2.3	229
…	30.3	122.474103517	3.01885247148	10.3936$\pm$0.0544	-16.952$\pm$0.099	-37.131$\pm$0.063	26.2	2516
31	31.1	124.747394623	-72.6653660338	12.3669$\pm$0.0194	-22.13$\pm$0.034	53.681$\pm$0.037	…	…
…	31.2	124.558006465	-72.6262036884	12.4117$\pm$0.0409	-21.677$\pm$0.073	53.863$\pm$0.083	247.5	19937
32	32.1	125.694579057	-57.4459684881	77.4877$\pm$0.0716	-372.239$\pm$0.157	481.326$\pm$0.157	…	…
…	32.2	125.696502898	-57.443984652	77.4495$\pm$0.0706	-371.155$\pm$0.165	437.05$\pm$0.158	8.1	104
33	33.1	127.026873626	-30.6754567721	6.9508$\pm$0.7706	-31.647$\pm$1.355	10.77$\pm$1.414	…	…
…	33.2	127.029755867	-30.6949199474	7.5778$\pm$0.0336	-31.421$\pm$0.042	7.343$\pm$0.048	70.6	9321
34	34.1	130.35521572	-57.6006901021	13.8219$\pm$0.0586	-22.963$\pm$0.13	22.945$\pm$0.116	…	…
…	34.2	130.355051694	-57.6002910335	13.776$\pm$0.071	-29.457$\pm$0.139	22.859$\pm$0.136	1.5	107
35	35.1	133.075291641	-19.2211391051	21.6057$\pm$0.0511	-60.649$\pm$0.071	50.531$\pm$0.058	…	…
…	35.2	133.062595689	-19.2473920359	21.3902$\pm$0.2603	-59.27$\pm$0.256	49.141$\pm$0.299	103.9	4857
36	36.1	133.186640696	22.5149166382	30.533$\pm$0.1048	-40.493$\pm$0.158	-153.386$\pm$0.1	…	…
…	36.2	133.185905577	22.5138295121	30.6652$\pm$0.1024	-36.737$\pm$0.155	-149.973$\pm$0.096	4.6	150
37	37.1	134.972160736	-20.9080635285	16.9812$\pm$0.0342	35.261$\pm$0.055	-72.393$\pm$0.049	…	…
…	37.2	134.977646101	-20.9081030456	16.7952$\pm$0.0895	33.204$\pm$0.155	-72.638$\pm$0.139	18.4	1098
38	38.1	136.022677642	-15.9219506654	36.6103$\pm$0.0483	-109.034$\pm$0.072	-32.638$\pm$0.076	…	…
…	38.2	136.085742643	-15.9143826651	36.52$\pm$0.0517	-107.828$\pm$0.083	-30.936$\pm$0.079	220.0	6025
39	39.1	138.148246805	-15.2844999181	22.0586$\pm$0.0493	-51.328$\pm$0.068	-42.01$\pm$0.093	…	…
…	39.2	138.140600035	-15.2900770922	21.9064$\pm$0.0545	-51.798$\pm$0.088	-43.857$\pm$0.111	33.3	1520
40	40.1	139.691670049	26.7515403197	40.3161$\pm$0.0716	-196.741$\pm$0.102	-353.518$\pm$0.072	…	…
…	40.2	139.671646501	26.7630015702	40.2542$\pm$0.1079	-194.238$\pm$0.15	-353.18$\pm$0.108	76.5	1899
41	41.1	145.658280011	-62.4837073856	23.5547$\pm$0.0847	-149.056$\pm$0.173	83.372$\pm$0.168	…	…
…	41.2	145.657482461	-62.4837573699	23.9316$\pm$0.0425	-158.669$\pm$0.08	73.762$\pm$0.114	1.3	56
…	41.3	145.645472032	-62.4758856653	23.9434$\pm$0.0238	-157.239$\pm$0.045	79.715$\pm$0.044	35.3	1475
42	42.1	153.089944124	-1.47119090641	25.1246$\pm$0.0727	-117.944$\pm$0.147	-10.212$\pm$0.207	…	…
…	42.2	153.08918359	-1.47086683642	25.1079$\pm$0.0777	-112.706$\pm$0.189	1.903$\pm$0.268	3.0	118
43	43.1	154.555865125	-20.4775953826	39.4836$\pm$0.087	-396.396$\pm$0.135	114.239$\pm$0.122	…	…
…	43.2	154.548627208	-20.4720560377	39.3106$\pm$0.0789	-390.304$\pm$0.132	116.753$\pm$0.112	31.5	802
44	44.1	155.518050963	-32.5575877603	8.2821$\pm$0.031	-120.028$\pm$0.053	-23.291$\pm$0.056	…	…
…	44.2	155.5142724	-32.5585139454	7.2181$\pm$0.7932	-120.84$\pm$1.348	-23.821$\pm$1.464	11.9	1654
45	45.1	156.355439692	-49.3105816883	39.1202$\pm$0.0508	-205.315$\pm$0.083	61.405$\pm$0.07	…	…
…	45.2	156.359926909	-49.3041217036	39.1902$\pm$0.0416	-201.765$\pm$0.068	68.964$\pm$0.057	25.5	651
46	46.1	179.956109675	-42.7405704848	16.1778$\pm$0.2008	-72.299$\pm$0.253	-16.576$\pm$0.201	…	…
…	46.2	179.970249869	-42.733752644	16.1329$\pm$0.0866	-73.037$\pm$0.105	-18.987$\pm$0.072	44.7	2772
47	47.1	182.970867544	12.8202838136	16.3878$\pm$0.0793	-71.618$\pm$0.13	-57.639$\pm$0.074	…	…
…	47.2	182.970853152	12.8199660561	16.1273$\pm$0.0976	-74.267$\pm$0.18	-63.983$\pm$0.092	1.1	71
…	47.3	183.035094024	12.8011015213	16.4079$\pm$0.0451	-73.195$\pm$0.071	-60.992$\pm$0.044	235.8	14371
48	48.1	186.683308106	-12.4884892808	33.3095$\pm$0.078	-161.876$\pm$0.148	-73.467$\pm$0.099	…	…
…	48.2	186.682789758	-12.4886743198	32.6332$\pm$0.079	-170.942$\pm$0.171	-89.395$\pm$0.101	1.9	59
49	49.1	203.881093361	-62.1871496784	4.6833$\pm$0.2095	-22.922$\pm$0.226	-12.044$\pm$0.277	…	…
…	49.2	203.860170132	-62.1851102716	4.0776$\pm$1.5383	-18.962$\pm$2.782	-11.943$\pm$3.049	35.9	8805
50	50.1	207.68317614	-21.6924529707	47.4932$\pm$0.0596	-35.895$\pm$0.113	-377.302$\pm$0.102	…	…
…	50.2	207.598875406	-21.6238049614	47.5095$\pm$0.0663	-33.504$\pm$0.111	-376.208$\pm$0.11	375.0	7893
51	51.1	220.495473154	-16.8880611197	46.683$\pm$0.0522	-170.941$\pm$0.093	-247.728$\pm$0.081	…	…
…	51.2	220.494457166	-16.8179334119	46.6443$\pm$0.0757	-171.652$\pm$0.125	-247.082$\pm$0.11	252.5	5413
52	52.1	220.908135379	-4.24352280153	19.3726$\pm$0.1992	-101.846$\pm$0.294	-69.609$\pm$0.275	…	…
…	52.2	220.907855485	-4.2434345354	19.4511$\pm$0.1454	-112.583$\pm$0.229	-66.234$\pm$0.203	1.1	54
53	53.1	237.528545136	-45.4227023254	21.3324$\pm$0.0492	32.526$\pm$0.109	-33.392$\pm$0.079	…	…
…	53.2	237.568220468	-45.4018597943	21.3601$\pm$0.0533	39.755$\pm$0.129	-33.474$\pm$0.068	125.2	5863
54	54.1	254.334352878	-53.7258072971	19.7563$\pm$0.12	-10.849$\pm$0.187	-84.087$\pm$0.143	…	…
…	54.2	254.339199055	-53.7247727621	19.8171$\pm$0.1371	-16.204$\pm$0.156	-85.696$\pm$0.138	11.0	554
55	55.1	261.990267808	-40.2737800294	24.9806$\pm$0.0702	-22.095$\pm$0.134	-61.126$\pm$0.094	…	…
…	55.2	261.989622771	-40.2736500924	25.025$\pm$0.065	-16.192$\pm$0.123	-58.788$\pm$0.087	1.8	73
56	56.1	272.81636071	-78.9886459065	85.2009$\pm$0.3832	97.719$\pm$0.717	275.387$\pm$0.759	…	…
…	56.2	272.814906041	-78.9883766915	85.8373$\pm$0.3909	60.499$\pm$0.728	304.053$\pm$0.745	1.4	16
57	57.1	273.543692455	-32.7931482752	13.8111$\pm$0.0642	3.491$\pm$0.111	-52.754$\pm$0.087	…	…
…	57.2	273.591990323	-32.7697082458	13.9995$\pm$0.0521	3.081$\pm$0.101	-52.639$\pm$0.08	168.8	12057
58	58.1	279.909851791	16.3866196343	14.3647$\pm$0.0404	-20.777$\pm$0.06	-106.458$\pm$0.072	…	…
…	58.2	279.899837715	16.3820506469	14.515$\pm$0.1599	-19.859$\pm$0.267	-107.222$\pm$0.33	38.3	2639
59	59.1	294.287243177	-51.5670290492	20.4834$\pm$0.0421	91.125$\pm$0.068	-26.99$\pm$0.048	…	…
…	59.2	294.284544043	-51.5687325295	20.4788$\pm$0.0579	87.338$\pm$0.085	-23.971$\pm$0.06	8.6	420
60	60.1	295.853742242	-37.3705104884	41.264$\pm$0.0648	162.885$\pm$0.098	-183.23$\pm$0.062	…	…
…	60.2	295.853258439	-37.3702613909	44.321$\pm$0.3694	155.208$\pm$0.539	-182.811$\pm$0.387	1.6	37
61	61.1	320.370809461	-66.9188363806	31.7121$\pm$0.3965	105.13$\pm$0.671	-85.324$\pm$0.782	…	…
…	61.2	320.353108276	-66.9163705624	31.2692$\pm$0.0434	95.668$\pm$0.062	-100.258$\pm$0.081	26.5	848
62	62.1	326.832200245	-48.0550277575	15.7704$\pm$0.1229	54.193$\pm$0.151	-89.707$\pm$0.215	…	…
…	62.2	326.816594573	-48.0445477226	15.9461$\pm$0.0552	49.848$\pm$0.07	-84.906$\pm$0.096	53.2	3338
63	63.1	332.922938405	-20.7366560482	24.1987$\pm$0.0867	147.272$\pm$0.138	-61.669$\pm$0.122	…	…
…	63.2	332.926084587	-20.7386890403	24.2517$\pm$0.0877	146.754$\pm$0.144	-64.44$\pm$0.126	12.9	531
64	64.1	342.48416723	17.744598513	13.0626$\pm$0.2053	-28.967$\pm$0.378	-64.631$\pm$0.29	…	…
…	64.2	342.480450677	17.7442276081	13.6598$\pm$0.126	-27.113$\pm$0.257	-55.2$\pm$0.178	12.8	938
65	65.1	347.973950223	-45.1338600039	21.1338$\pm$0.1211	74.896$\pm$0.105	-94.183$\pm$0.172	…	…
…	65.2	347.967423785	-45.1366897831	20.8274$\pm$0.0683	87.469$\pm$0.05	-93.499$\pm$0.091	19.5	934
66	66.1	350.19685687	-67.3896567818	24.3611$\pm$0.0738	78.28$\pm$0.12	-81.043$\pm$0.119	…	…
…	66.2	350.197395285	-67.3888825742	24.4343$\pm$0.0656	84.043$\pm$0.104	-78.354$\pm$0.101	2.9	118
67	67.1	351.888430293	-22.0418804446	14.5199$\pm$0.1203	61.6$\pm$0.233	-50.315$\pm$0.173	…	…
…	67.2	351.885024487	-22.0388739146	14.577$\pm$0.0509	60.982$\pm$0.103	-50.158$\pm$0.074	15.7	1077
68	68.1	353.342398779	-12.6685927216	27.809$\pm$0.4086	189.131$\pm$0.549	24.159$\pm$0.49	…	…
…	68.2	353.350093919	-12.664513128	29.4073$\pm$0.064	185.523$\pm$0.091	24.355$\pm$0.078	30.8	1046
69	69.1	358.423396079	-65.9480499764	39.5909$\pm$0.0328	-43.768$\pm$0.047	87.533$\pm$0.047	…	…
…	69.2	358.415716065	-65.9467703123	39.5453$\pm$0.0268	-42.373$\pm$0.039	84.84$\pm$0.044	12.2	308

Table 5. Table 5: Moving Group Evaluation Summary

Group	Age	Age	NewaaThis number includes those objects that have been previously suggested to be a member of a different group, but have been reassigned in this work to this group.	Confirmed	Rejected
Name	(Myr)	Ref.	Members	Members	Members
AB Dor	149${}_{-19}{}^{}{}_{}{}^{+51}$	1	0	13	5
Argus	40-50	2	0	7	21
$\beta$ Pictoris	22$\pm$6	3	1	8	10
Carina	45${}_{-7}{}^{}{}_{}{}^{+11}$	1	3	8	1
Carina-Near	$\sim$200	4	6	0	0
Columba	42${}_{-4}{}^{}{}_{}{}^{+6}$	1	1	10	5
$ϵ$ Cha	3.7${}_{-1.4}{}^{}{}_{}{}^{+4.6}$	5	0	4	0
$\eta$ Cha	11$\pm$3	1	0	8	0
Octans	35$\pm$5	6	0	1	0
Tuc-Hor	45$\pm$4	1	3	4	2
\colruleTotal			14	63	46

Table 6. Table 6: New and Confirmed Moving Group Members

2MASS	Spec.	Li EWaa‘Y’ refers to completely new members, while ‘R’ refers to reassigned members (i.e., those objects previously proposed to belong to a different group).	H$\alpha$ EW	log $L_X$	$f_{\mathrm{FUV}}$/$f_J$	$f_{\mathrm{NUV}}$/$f_J$	XYZ	UVW	BANYAN $\Sigma$	New?   aa‘Y’ refers to completely new members, while ‘R’ refers to reassigned members (i.e., those objects previously proposed to belong to a different group).
Name	Type	(Å)	(Å)	(erg s-1)			(pc)	(km s-1)	(%)
\colrule            AB Dor
\colrule01484087$-$4830519	M1.5	…	-2.68	29.36$\pm$0.07	3.41e-05	2.04e-04	(2.58,-15.78,-35.74)	(-7.51,-28.13,-11.48)	99.8	…
02130073$+$1803460	M4.5	…	-5.49	…	6.33e-05	2.05e-04	(-17.55,10.62,-17.63)	(-5.33,-27.42,-15.48)	99.9	…
03100305$-$2341308	M3.5	…	-6.20	…	7.96e-05	2.09e-04	(-11.31,-7.77,-22.49)	(-4.75,-27.53,-16.92)	99.3	…
04084031$-$2705473	M4.0	…	-3.60	28.92$\pm$0.10	8.77e-05	2.13e-04	(-15.80,-15.64,-23.35)	(-5.47,-28.22,-16.53)	99.6	…
04353618$-$2527347	M3.5	…	-5.80	28.71$\pm$0.08	5.37e-05	2.28e-04	(-9.15,-8.98,-10.82)	(-5.10,-28.05,-18.16)	98.4	…
04514615$-$2400087	M3.0	…	-6.23	29.17$\pm$0.09	…	2.24e-04	(-29.39,-28.34,-29.91)	(-4.47,-26.77,-8.52)	65.2	…
05531299$-$4505119	M0.5	0.132	-1.57	29.23$\pm$0.04	1.86e-05	…	(-8.58,-25.99,-15.01)	(-8.05,-28.67,-12.02)	99.9	…
06373215$-$2823125	M2.5	…	-1.79	29.14$\pm$0.10	…	…	(-22.44,-35.02,-11.40)	(-8.13,-27.50,-15.07)	99.9	…
12383713$-$2703348	M2.5	…	-2.31	28.80$\pm$0.10	2.10e-05	1.22e-04	(9.92,-17.60,14.53)	(-7.43,-28.51,-11.92)	99.7	…
14415908$-$1653133	M3.0	…	0.00	…	1.88e-04	2.11e-04	(15.49,-6.43,13.32)	(-11.76,-25.47,-16.49)	60.2	…
21464282$-$8543046	M3.5	…	-10.46	28.82$\pm$0.05	6.23e-05	…	(8.00,-10.82,-7.78)	(-7.52,-27.45,-13.94)	100.0	…
21471964$-$4803166	M4.0	…	-6.72	29.32$\pm$0.11	4.94e-05	1.76e-04	(41.13,-7.39,-47.70)	(-5.68,-29.52,-14.00)	16.5	…
23115362$-$4508004	M3.0	…	-6.41	29.81$\pm$0.07	6.51e-05	…	(20.51,-5.83,-42.24)	(-4.67,-26.66,-10.46)	84.1	…
\colrule            Argus
\colrule05471788$-$2856130	M3.5	…	-5.54	29.64$\pm$0.07	…	…	(-33.46,-45.69,-27.42)	(-20.98,-15.20,-4.12)	99.7	…
09445422$-$1220544	M5.0	…	-16.17	28.71$\pm$0.04	3.94e-05	1.25e-04	(-4.28,-10.54,6.56)	(-22.36,-13.61,-3.75)	99.5	…
10252563$-$4918389	M4.0	…	-4.52	28.86$\pm$0.09	…	…	(4.38,-25.00,3.08)	(-24.26,-6.60,-6.75)	5.9	…
12233860$-$4606203	M4.0	…	-5.08	28.71$\pm$0.09	…	1.17e-04	(10.29,-19.42,6.51)	(-24.03,-8.03,-5.63)	89.4	…
17275761$-$4016243	M4.0	…	-7.81	28.91$\pm$0.14	…	…	(39.17,-7.98,-2.12)	(-20.07,-8.15,-1.98)	81.4	…
20072376$-$5147272	K6.0	…	-0.99	29.79$\pm$0.04	4.58e-05	3.75e-04	(27.96,-6.54,-18.30)	(-25.74,-16.72,-5.09)	95.3	…
22274882$-$0113527	M3.5	…	-3.64	28.98$\pm$0.10	9.73e-05	…	(8.95,18.16,-21.66)	(-24.17,-16.59,-0.16)	84.4	…
\colrule            $\beta$ Pic
\colrule02442137$+$1057411	M1.0	0.739	-2.63	…	…	…	(-33.95,10.76,-33.31)	(-8.96,-18.36,-5.00)	3.9	…
02490228$-$1029220	M2.0	0.266	-2.42	29.34$\pm$0.20	3.97e-05	1.78e-04	(-20.65,-2.75,-32.97)	(-12.38,-10.28,-11.32)	1.3	…
05082729$-$2101444	M5.0	…	-24.90	28.89$\pm$0.13	2.57e-05	1.53e-04	(-30.78,-27.73,-25.52)	(-14.65,-20.39,-7.73)	2.5	…
05294468$-$3239141	M4.5	…	-5.88	29.03$\pm$0.08	2.27e-05	1.03e-04	(-14.16,-21.49,-15.16)	(-11.90,-16.36,-9.04)	99.9	…
05320450$-$0305291	M2.0	0.073	-3.02	29.80$\pm$0.04	…	1.93e-04	(-29.25,-14.56,-11.27)	(-19.08,-15.64,-8.73)	51.3	…
09462782$-$4457408	M5.5	0.542	-13.61	…	…	…	(1.60,-46.39,5.29)	(-13.99,-17.17,-7.78)	40.9	Y
13545390$-$7121476	M2.5	…	-2.84	28.86$\pm$0.06	…	2.32e-04	(13.89,-17.78,-3.62)	(-12.02,-15.03,-10.41)	99.4	…
16572029$-$5343316	M3.0	…	-0.78	29.14$\pm$0.16	…	…	(45.37,-21.65,-5.88)	(-7.12,-15.99,-10.52)	98.7	…
19233820$-$4606316	M0.0	0.447	-1.01	29.75$\pm$0.11	3.04e-05	3.32e-04	(64.02,-9.10,-29.50)	(-7.02,-16.34,-9.64)	97.0	…
\colrule            Carina
\colrule06112997$-$7213388	M4.0	…	-6.16	29.40$\pm$0.06	4.56e-05	1.42e-04	(11.12,-48.65,-27.40)	(-11.88,-24.50,-4.88)	97.7	…
06234024$-$7504327	M3.5	…	-5.65	29.52$\pm$0.33	…	…	(11.77,-40.75,-22.48)	(-5.30,-20.45,-6.12)	98.6	…
07013884$-$6236059	M0.5	…	-1.54	29.70$\pm$0.05	9.52e-05	2.66e-04	(4.33,-81.70,-34.29)	(-11.40,-23.04,-4.93)	94.6	Y
07065772$-$5353463	M0.0	0.380	-1.36	29.66$\pm$0.06	4.46e-05	1.83e-04	(-4.32,-43.79,-15.54)	(-10.75,-20.78,-6.24)	96.2	RccPreviously suggested to be a member of the Columba association in Malo et al. (2013, 2014).
08040534$-$6316396	M2.0	…	-5.17	29.81$\pm$0.09	…	…	(8.46,-74.44,-22.07)	(-11.13,-22.50,-6.22)	100.0	…
08194309$-$7401232	M4.5	…	-9.80	29.49$\pm$0.13	…	1.48e-04	(17.96,-58.19,-22.48)	(-9.29,-28.84,-8.53)	82.7	…
08412528$-$5736021	M3.0	…	-7.24	…	…	…	(5.13,-71.17,-11.93)	(-9.49,-21.70,-5.11)	96.7	…
09032434$-$6348330	M0.5	0.380	-2.14	29.92$\pm$0.08	…	…	(14.38,-75.70,-15.34)	(-10.58,-22.68,-6.44)	100.0	…
09180165$-$5452332	M4.0	0.285	-8.96	29.25$\pm$0.13	…	…	(4.95,-52.65,-3.57)	(-11.61,-26.26,-6.41)	96.9	…
09315840$-$6209258	M3.5	…	-6.15	29.94$\pm$0.09	…	…	(15.90,-76.08,-10.61)	(-10.24,-21.08,-6.19)	99.9	…
14284804$-$7430205	M1.0	0.099	-2.19	29.66$\pm$0.08	…	…	(36.41,-44.30,-13.11)	(-9.25,-20.94,-5.72)	4.2	RddPreviously suggested to be a member of the Argus association in Malo et al. (2013).
\colrule            Carina-Near
\colrule06134171$-$2815173	M3.5	…	-5.93	29.16$\pm$0.07	6.09e-05	3.04e-04	(-22.08,-31.75,-14.18)	(-28.32,-16.28,0.85)	9.5	Y
06380031$-$4056011	M3.5	…	-6.52	28.98$\pm$0.09	…	…	(-12.60,-34.01,-13.03)	(-25.58,-18.93,-3.29)	99.7	RddPreviously suggested to be a member of the Argus association in Malo et al. (2013).
07170438$-$6311123	M2.0	…	-4.43	29.41$\pm$0.07	…	…	(4.43,-60.49,-23.56)	(-13.61,-13.78,-4.57)	1.6	RffPreviously suggested as an ambiguous $\beta$ Pic/Carina/Columba/AB Dor member in Malo et al. (2013)
11462310$-$5238519	M4.5	…	-8.46	…	…	3.55e-04	(22.38,-52.65,9.03)	(-19.04,-16.72,-1.61)	45.9	RbbPreviously suggested to be a member of the Scorpius-Centaurus OB association in Rodriguez et al. (2011).
19435432$-$0546363	M4.0	…	-5.65	28.94$\pm$0.11	6.12e-05	1.71e-04	(23.53,15.70,-7.21)	(-31.38,-15.13,1.45)	65.3	RddPreviously suggested to be a member of the Argus association in Malo et al. (2013).
20284361$-$1128307	M3.5	…	-6.30	28.85$\pm$0.07	4.88e-05	1.83e-04	(13.65,8.99,-8.23)	(-23.85,-17.91,-3.00)	70.0	ReePreviously suggested to be a member of the Argus association in Riedel et al. (2014).
\colrule            Columba
\colrule03241504$-$5901125	K7.0	0.224	-0.94	29.75$\pm$0.10	4.62e-05	3.35e-04	(4.10,-57.06,-65.05)	(-11.03,-22.83,-5.04)	8.2	…
03320347$-$5139550	M2.0	…	-2.06	29.75$\pm$0.07	2.33e-05	1.43e-04	(-5.66,-47.72,-59.82)	(-12.39,-21.79,-3.71)	97.5	…
04091413$-$4008019	M3.5	…	-6.04	29.59$\pm$0.12	3.26e-05	1.90e-04	(-22.59,-45.88,-55.64)	(-12.70,-21.84,-4.39)	99.9	…
05100427$-$2340407	M3.0	…	-2.20	29.89$\pm$0.05	3.69e-05	1.47e-04	(-34.45,-34.58,-30.66)	(-14.04,-22.04,-5.26)	99.9	…
05100488$-$2340148	M2.0	…	-6.63	…	5.94e-05	2.25e-04	(-34.60,-34.73,-30.79)	(-13.01,-22.52,-5.76)	100.0	…
05175793$-$5433503	M2.0	…	-5.96	29.72$\pm$0.13	…	1.09e-04	(-8.11,-60.00,-42.68)	(-12.16,-22.91,-5.10)	83.4	Y
05195695$-$1124440	M3.5	…	-9.91	29.65$\pm$0.09	…	1.74e-04	(-53.30,-34.72,-30.24)	(-14.30,-21.71,-5.51)	99.2	…
05241317$-$2104427	M4.0	…	-4.84	29.25$\pm$0.11	…	…	(-37.13,-35.27,-27.45)	(-13.62,-21.95,-6.02)	100.0	…
05395494$-$1307598	M3.0	…	-3.65	29.51$\pm$0.13	…	…	(-58.54,-44.11,-29.17)	(-15.50,-22.55,-6.76)	42.7	…
05432676$-$3025129	M0.5	…	-2.60	29.97$\pm$0.07	…	…	(-44.52,-63.78,-39.77)	(-14.45,-23.33,-8.36)	1.3	…
06262932$-$0739540	M1.0	0.228	-2.43	…	…	…	(-64.68,-48.69,-12.84)	(-12.56,-20.72,-6.11)	71.5	…
\colrule            $ϵ$ Cha
\colrule11493184$-$7851011	M0.0	0.579	-2.96	30.07$\pm$0.06	8.10e-05	3.25e-04	(48.15,-83.91,-28.38)	(-9.77,-20.95,-11.13)	99.9	…
12194369$-$7403572	M1.0	0.575	-4.13	…	…	2.03e-04	(50.77,-85.45,-19.92)	(-9.25,-21.01,-9.65)	99.8	…
12202177$-$7407393	M1.0	0.663	-3.69	…	1.29e-04	1.96e-04	(74.70,-125.45,-29.40)	(-18.45,-24.39,-8.85)	20.9	…
12210499$-$7116493	K7.0	0.549	-0.93	30.32$\pm$0.09	…	…	(49.88,-84.76,-14.79)	(-9.19,-20.65,-8.84)	95.4	…
\colrule            $\eta$ Cha
\colrule08361072$-$7908183	M5.5	0.621	-9.65	…	…	…	(34.85,-84.45,-36.82)	(-10.89,-20.99,-11.38)	92.2	…
08385150$-$7916136	M5.0	0.652	-10.67	…	…	…	(35.83,-86.00,-37.47)	(-10.72,-20.74,-11.49)	38.7	…
08413030$-$7853064	M5.0	0.685	-8.46	…	…	…	(34.91,-84.97,-36.38)	(-11.89,-20.35,-11.09)	41.6	…
08413703$-$7903304	M3.5	0.529	-2.63	…	…	…	(35.13,-84.83,-36.52)	(-10.95,-20.58,-10.84)	57.6	…
08422710$-$7857479	M4.0	0.680	-4.51	…	…	…	(35.04,-84.88,-36.37)	(-11.25,-20.86,-11.57)	38.9	…
08423879$-$7854427	M3.0	0.487	-4.25	29.00$\pm$0.29	…	…	(34.76,-84.37,-36.07)	(-10.68,-20.98,-11.22)	84.9	…
08440914$-$7833457	M4.5	0.536	-63.46	…	…	…	(34.54,-84.99,-35.81)	(-10.90,-20.35,-11.14)	79.1	…
08441637$-$7859080	M4.5	0.643	-10.14	…	…	…	(34.63,-83.59,-35.72)	(-11.35,-20.65,-12.92)	99.6	…
\colrule            Octans
\colrule02411909$-$5725185	M3.0	…	-4.63	29.57$\pm$0.14	2.20e-05	1.71e-04	(7.11,-51.18,-71.23)	(-12.82,-2.56,-8.81)	100.0	…
\colrule            Tuc-Hor
\colrule00153670$-$2946003	M4.0	…	-6.32	28.76$\pm$0.15	2.32e-05	1.33e-04	(5.15,1.12,-36.09)	(-9.60,-20.98,-2.64)	99.9	…
03454058$-$7509121	M4.0	…	-8.36	29.34$\pm$0.07	…	1.61e-04	(15.69,-42.86,-34.78)	(-9.61,-21.19,-1.00)	100.0	…
05142736$-$1514514	M3.5	…	-5.42	29.74$\pm$0.08	…	…	(-53.96,-39.79,-35.95)	(-13.54,-22.30,-2.33)	20.4	RccPreviously suggested to be a member of the Columba association in Malo et al. (2013, 2014).
05142878$-$1514546	M3.5	…	-4.53	…	…	…	(-53.75,-39.64,-35.80)	(-13.16,-21.71,-2.39)	24.1	RccPreviously suggested to be a member of the Columba association in Malo et al. (2013, 2014).
06002304$-$4401217	M4.0	…	-13.98	29.75$\pm$0.05	…	…	(-20.16,-58.02,-31.67)	(-11.70,-23.70,-3.12)	59.9	RccPreviously suggested to be a member of the Columba association in Malo et al. (2013, 2014).
19225071$-$6310581	M3.0	…	-6.21	29.65$\pm$0.12	5.47e-05	1.88e-04	(41.60,-21.03,-24.27)	(-8.68,-19.27,-0.01)	97.9	…
23204705$-$6723209	M5.0	…	-9.69	29.25$\pm$0.08	8.26e-05	2.34e-04	(19.83,-19.43,-30.24)	(-8.74,-21.03,-0.55)	99.9	…

Table 7. Table 7: Rejected Moving Group Members

2MASS	Spec.	Li EWaafootnotemark:	H$\alpha$ EW	log $L_X$	$f_{\mathrm{FUV}}$/$f_J$	$f_{\mathrm{NUV}}$/$f_J$	XYZ	UVW	Reassigned?
Name	Type	(Å)	(Å)	(erg s-1)			(pc)	(km s-1)
\colrule            AB Dor
\colrule02523096$-$1548357	M2.5	…	-2.35	29.72$\pm$0.17	3.43e-05	1.71e-04	(-54.46,-16.88,-97.76)	(-30.87,-79.45,-54.38)	…
04424932$-$1452268	M4.0	…	-6.00	29.00$\pm$0.10	…	1.75e-04	(-24.41,-15.55,-20.33)	(-1.67,-30.52,-13.76)	…
05130132$-$7027418	M3.5	…	-5.11	29.16$\pm$0.04	…	5.45e-05	(5.38,-26.40,-17.91)	(-37.95,-8.56,8.43)	…
05240991$-$4223054	M0.5	…	-2.41	29.80$\pm$0.09	…	1.84e-04	(-31.89,-77.48,-55.42)	(-11.00,-31.02,-11.84)	…
07115917$-$3510157	M3.0	…	-4.86	29.11$\pm$0.09	…	…	(-14.27,-33.25,-7.29)	(10.52,4.10,-5.89)	…
\colrule            Argus
\colrule00503319$+$2449009A	M3.5	…	-4.18	28.97$\pm$0.06	6.59e-05	1.57e-04	(-6.36,9.92,-9.23)	(-13.79,-5.23,-5.34)	…
00503319$+$2449009B	M3.5	…	-4.53	…	6.59e-05	1.57e-04	(-6.36,9.92,-9.23)	(-13.76,-5.28,-5.30)	…
03282609$-$0537361	M4.0	…	-4.32	28.26$\pm$0.18	2.06e-05	9.95e-05	(-18.84,-3.38,-20.48)	(-25.43,-16.13,-12.27)	…
03415581$-$5542287	M4.5	…	-7.28	…	1.51e-04	1.83e-04	(-0.63,-18.14,-20.31)	(-43.27,-26.49,-9.91)	…
03415608$-$5542408	M4.0	…	-3.84	28.47$\pm$0.10	…	9.50e-05	(-0.63,-18.14,-20.31)	(-43.04,-19.94,-2.58)	…
04464970$-$6034109	M1.5	…	-4.42	28.99$\pm$0.05	…	…	(0.13,-19.20,-15.31)	(-14.20,-7.41,-1.88)	…
04595855$-$0333123	M4.0	…	-5.50	29.46$\pm$0.10	8.52e-05	1.63e-04	(-50.26,-21.13,-26.97)	(-44.90,-19.46,1.19)	…
06380031$-$4056011	M3.5	…	-6.52	28.98$\pm$0.09	…	…	(-12.60,-34.01,-13.03)	(-25.58,-18.93,-3.29)	Y
07343426$-$2401353	M3.5	…	-6.19	29.06$\pm$0.13	…	…	(-21.54,-35.95,-1.41)	(-16.88,-18.69,-3.72)	…
09423823$-$6229028	M3.5	…	-1.24	29.19$\pm$0.10	…	…	(9.44,-41.05,-5.31)	(-30.35,-18.15,-8.55)	…
09455843$-$3253299	M4.5	…	-8.60	28.41$\pm$0.06	4.01e-05	1.06e-04	(-1.25,-11.51,3.22)	(-21.09,-24.78,2.03)	…
11200609$-$1029468	M2.0	…	-1.42	29.01$\pm$0.05	1.02e-05	1.08e-04	(-0.14,-13.05,13.68)	(-16.40,-13.75,3.95)	…
13283294$-$3654233	M3.5	…	-2.47	28.88$\pm$0.13	…	1.20e-04	(21.27,-24.35,15.34)	(-39.22,-8.01,-5.41)	…
13382562$-$2516466	M3.5	…	-3.73	29.25$\pm$0.07	7.79e-05	2.95e-04	(18.11,-17.40,18.51)	(-59.23,-10.66,-20.64)	…
13591045$-$1950034	M4.5	…	-4.63	28.33$\pm$0.07	1.66e-05	6.18e-05	(6.68,-4.86,6.99)	(-28.11,-16.99,-9.81)	…
14284804$-$7430205	M1.0	0.099	-2.19	29.66$\pm$0.08	…	…	(36.41,-44.30,-13.11)	(-9.25,-20.94,-5.72)	Y
19432464$-$3722108	M3.5	…	-7.41	28.60$\pm$0.13	…	…	(21.79,0.87,-10.56)	(-45.72,-17.12,-3.86)	…
19435432$-$0546363	M4.0	…	-5.65	28.94$\pm$0.11	6.12e-05	1.71e-04	(23.53,15.70,-7.21)	(-31.38,-15.13,1.45)	Y
20163382$-$0711456	M0.0	…	-0.35	29.06$\pm$0.09	1.40e-05	1.30e-04	(25.59,18.73,-12.93)	(-23.01,-5.84,5.44)	…
20284361$-$1128307	M3.5	…	-6.30	28.85$\pm$0.07	4.88e-05	1.83e-04	(13.65,8.99,-8.23)	(-23.85,-17.91,-3.00)	Y
23332198$-$1240072	K5.0	…	-3.54	28.99$\pm$0.11	5.38e-05	…	(5.46,13.14,-33.03)	(-27.22,-1.99,-25.93)	…
\colrule            $\beta$ Pic
\colrule05332802$-$4257205	M4.5	…	-2.95	28.43$\pm$0.04	2.77e-05	9.80e-05	(-3.21,-8.18,-5.46)	(-0.30,4.85,2.09)	…
05422387$-$2758031	M4.5	…	-8.50	29.57$\pm$0.08	9.63e-05	2.28e-04	(-36.00,-46.73,-29.48)	(-4.12,-9.55,-5.49)	…
06135773$-$2723550	G5.0	0.076	-5.55	31.16$\pm$0.07	7.67e-05	7.72e-04	(-204.69,-285.40,-126.33)	(1.59,13.84,9.77)	…
08224744$-$5726530	M4.5	…	-6.09	28.34$\pm$0.05	…	…	(0.56,-12.64,-2.56)	(-36.48,-15.61,-5.83)	…
10571139$+$0544547	M1.0	…	-1.33	30.09$\pm$0.09	5.67e-05	2.81e-04	(-24.25,-54.39,86.41)	(-18.97,-29.34,-10.74)	…
11493184$-$7851011	M0.0	0.579	-2.96	30.07$\pm$0.06	8.10e-05	3.25e-04	(48.15,-83.91,-28.38)	(-9.77,-20.95,-11.13)	Y
12115308$+$1249135	M0.0	…	-0.14	…	1.73e-05	1.37e-04	(-0.60,-17.87,58.34)	(-9.78,-23.56,-7.58)	…
14255593$+$1412101	M0.0	0.150	-3.89	31.36$\pm$0.03	9.94e-05	4.48e-04	(68.11,8.69,143.77)	(-42.49,-49.88,-44.76)	…
17150219$-$3333398	M0.0	…	-1.99	29.45$\pm$0.05	…	…	(25.66,-3.36,1.31)	(-29.97,-13.39,-15.20)	…
23301341$-$2023271	M3.0	…	-3.60	29.08$\pm$0.04	…	1.07e-04	(3.57,4.04,-15.02)	(-15.82,-24.87,-1.75)	…
\colrule            Carina
\colrule08185942$-$7239561	M0.0	…	-0.68	29.64$\pm$0.10	…	1.77e-04	(20.81,-73.25,-27.20)	(-14.42,-30.25,-6.38)	…
\colrule            Columba
\colrule04322548$-$3903153	M3.5	…	-5.20	28.92$\pm$0.10	…	1.42e-04	(-11.00,-20.94,-22.01)	(-10.04,-3.91,-7.96)	…
05425587$-$0718382	M3.0	…	-13.96	29.73$\pm$0.09	…	2.86e-04	(-66.33,-41.01,-26.15)	(-26.72,-26.73,-12.38)	…
06511418$-$4037510	non-M	…	1.49	…	…	6.46e-05	(-454.65,-1268.70,-419.99)	(-48.55,-0.76,7.54)	…
07065772$-$5353463	M0.0	0.380	-1.36	29.66$\pm$0.06	4.46e-05	1.83e-04	(-4.32,-43.79,-15.54)	(-10.75,-20.78,-6.24)	Y
23301341$-$2023271	M3.0	…	-3.60	29.08$\pm$0.04	…	1.07e-04	(3.57,4.04,-15.02)	(-15.82,-24.87,-1.75)	…
\colrule            Tuc-Hor
\colrule02511150$-$4753077	K5.0	…	-0.83	31.15$\pm$0.08	6.83e-05	6.50e-04	(-25.06,-194.89,-324.57)	(2.01,-2.29,18.89)	…
06434532$-$6424396	M3.0	…	-5.38	28.77$\pm$0.18	1.07e-04	5.11e-04	(1.42,-18.25,-8.57)	(-2.75,-19.14,-7.98)	…

Table 8. Table 8: Low-Probability Candidate Members

2MASS	Spec.	Li EWaafootnotemark:	H$\alpha$ EW	log $L_X$	$f_{\mathrm{FUV}}$/$f_J$	$f_{\mathrm{NUV}}$/$f_J$	XYZ	UVW	$\sigma$dist	$\sigma$RV
Name	Type	(Å)	(Å)	(erg s-1)			(pc)	(km s-1)
\colrule            AB Dor
\colrule04424932$-$1452268	M4.0	…	-6.00	29.00$\pm$0.10	…	1.75e-04	(-24.41,-15.55,-20.33)	(-1.67,-30.52,-13.76)	4.45	0.16
05240991$-$4223054	M0.5	…	-2.41	29.80$\pm$0.09	…	1.84e-04	(-31.89,-77.48,-55.42)	(-11.00,-31.02,-11.84)	3.08	1.74
11091606$-$7352465	M3.0	…	-3.49	29.59$\pm$0.13	6.03e-05	2.25e-04	(27.81,-57.30,-14.03)	(-7.11,-24.57,-7.39)	1.80	1.60
\colrule            $\beta$ Pic
\colrule11091606$-$7352465	M3.0	…	-3.49	29.59$\pm$0.13	6.03e-05	2.25e-04	(27.81,-57.30,-14.03)	(-7.11,-24.57,-7.39)	1.76	2.48
\colrule            Carina
\colrule11091606$-$7352465	M3.0	…	-3.49	29.59$\pm$0.13	6.03e-05	2.25e-04	(27.81,-57.30,-14.03)	(-7.11,-24.57,-7.39)	4.34	1.68
\colrule            Carina-Near
\colrule07343426$-$2401353	M3.5	…	-6.19	29.06$\pm$0.13	…	…	(-21.54,-35.95,-1.41)	(-16.88,-18.69,-3.72)	3.15	0.47
08224744$-$5726530	M4.5	…	-6.09	28.34$\pm$0.05	…	…	(0.56,-12.64,-2.56)	(-36.48,-15.61,-5.83)	8.84	2.99
09423823$-$6229028	M3.5	…	-1.24	29.19$\pm$0.10	…	…	(9.44,-41.05,-5.31)	(-30.35,-18.15,-8.55)	8.80	2.22
13591045$-$1950034	M4.5	…	-4.63	28.33$\pm$0.07	1.66e-05	6.18e-05	(6.68,-4.86,6.99)	(-28.11,-16.99,-9.81)	1.07	5.85
\colrule            Columba
\colrule07343426$-$2401353	M3.5	…	-6.19	29.06$\pm$0.13	…	…	(-21.54,-35.95,-1.41)	(-16.88,-18.69,-3.72)	5.02	1.53

Equations

$$L_{\mathrm{X}}=1.2^{38}{f}_{\mathrm{X}}{d}^2$$

Full text

stars: low-mass

††journal: AJ

1 Introduction

The discovery of young stars ($<$300 Myr) in the neighborhood of the Sun ($<$100 pc) has allowed for significant advances in several areas of astrophysics. Because of their age and proximity, such stars are optimal targets for directly detecting low-mass planetary companions (e.g., Chauvin et al. 2004, 2005, Marois et al. 2008, 2010, Lagrange et al. 2010, Bowler et al. 2013, 2017, Naud et al. 2014, Chauvin et al. 2017, Dupuy et al. 2018), in-depth studies of circumstellar disks (e.g., Su et al. 2006, Rebull et al. 2008, Zuckerman et al. 2011, Riviere-Marichalar et al. 2014, Rodriguez et al. 2015, Binks & Jeffries 2017, Meng et al. 2017), mass function investigations (e.g., Kraus et al. 2014, Shkolnik et al. 2017, Gagné et al. 2017a), and studies of various evolutionary properties ranging from rotation and activity (e.g., Montes et al. 2001 de la Reza & Pinzón 2004, Malo et al. 2014, Shkolnik & Barman 2014, Schneider & Shkolnik 2018) to chemical abundances (e.g., Mentuch et al. 2008, da Silva et al. 2009, Viana Almeida et al. 2009, Žerjal et al. 2019) to multiplicity (e.g, Janson et al. 2014, Shan et al. 2017) to empirical isochrones (e.g, Liu et al. 2016).

Nearby, young moving groups are coeval collections of stars that share the same age and similar space motions (e.g., Kastner et al. 1997). Confirming membership to these kinematically linked groups requires knowledge of an object’s distance, proper motion, radial velocity, and age. While proper motions have typically been available from numerous all-sky surveys, accurate distances and radial velocities have been more difficult to acquire as they require dedicated observations. With the second data release of the Gaia mission (hereafter Gaia DR2; Gaia Collaboration et al. 2016, 2018), parallaxes are now readily available for the vast majority of nearby, stellar moving group members. Such data is being used to identify new moving group members as well as completely new moving groups (e.g., Faherty et al. 2018, Gagné et al. 2018d). In many instances, the only pieces of information now missing to confirm a potential moving group member are its radial velocity and youth. The Gaia mission will eventually include radial velocities for $\sim$150 million stars (Soubiran et al., 2018), and the DR2 release includes radial velocities for over 7 million bright stars, though with increasing uncertainties at the faint end ($\gtrsim$2 km s*-1*; Gaia Collaboration et al. 2018). In this third installment of the All-sky Co-moving Recovery Of Nearby Young Members (ACRONYM) series (Kraus et al. 2014, Shkolnik et al. 2017), we present radial velocities and youth characteristics for 336 nearby, low-mass stars that are suspected to be young in order to identify new, and confirm previously proposed, moving group members.

2 Observations

Nearby young candidates were observed with the goal of identifying young, nearby, low-mass stars. These include the list of X-ray active M dwarfs from the NStars catalog (Reid et al., 2003, 2004) and from Riaz et al. (2006), kinematic moving group candidates from Malo et al. (2013), and UV-active M dwarfs using the methods outlined in Shkolnik et al. (2011). For X-ray active M dwarfs, we required the log of the X-ray flux ($F_{\rm X}$) to 2MASS $J$-band flux ($F_{J}$) to be greater than –2.5, a value chosen to be comparable to members of the Pleiades (Shkolnik et al., 2009). For UV-active M dwarf candidates, we required 3$\sigma$ detections in both the GALEX FUV and NUV bands, and required the FUV and NUV to 2MASS $J$-band flux ratios to be greater than 10*-5* and 10*-4*, respectively (Shkolnik et al., 2011). High resolution optical spectra were acquired for all targets to measure radial velocities and youth diagnostics. Radial velocity standards were observed each night in order to determine radial velocities of our target stars. Care was taken to observe radial velocity standards with similar spectral types as the target sample. All observations are summarized in Table 1.

2.1 Keck/HIRES

Fifty-two targets were observed with the High Resolution Echelle Spectrometer (HIRES; Vogt et al. 1994) on the Keck I telescope. The observing strategy and data reduction routine are outlined in Shkolnik et al. (2009, 2017), which we briefly summarize here. All observations were taken with the 0$\farcs$861 slit, resulting in a spectral resolution of $\lambda$/\Delta$$\lambda $\approx$ 58,000 covering a wavelength range of 4900–9300 Å. The GG475 filter was utilized with the red cross-disperser in order to maximize the throughput at the longest wavelengths (where M dwarfs emit their peak emission). All data reduction was accomplished using the facility pipeline MAKEE.

2.2 CFHT/ESPaDOnS

We observed 15 targets with the Echelle SpectroPolarimatric Device for the Observation of Stars (ESPaDOnS; Donati et al. 2006) on the Canada-France-Hawaii Telescope (CFHT). The observing strategy and data reduction routine are outlined in Shkolnik et al. (2009), which we briefly summarize here. ESPaDOnS covers a wavelength range of 3700–10400 Å, with a spectral resolution of $\lambda$/\Delta$$\lambda $\approx$ 68,000. Data reduction was achieved using the fully automated reduction package Libre ESpRIT (Donati et al., 2007).

2.3 Magellan/MIKE

The Magellan Inamori Kyocera Echelle (MIKE) optical spectrograph located on the Clay telescope at the Magellan Observatory was used to characterize 122 of our targets. The observing strategy and data reduction routine are outlined in Shkolnik et al. (2011, 2017), which we briefly summarize here. We used the 0$\farcs$5 slit with for all MIKE observations, which gives a spectral resolution of $\lambda$/\Delta$$\lambda $\approx$ 35,000 over the wavelength range 4900–10000 Å. All MIKE data were reduced using the CarPy pipeline (Kelson et al., 2000; Kelson, 2003).

2.4 Du Pont/Echelle

Two-hundred and twenty-nine targets were observed with the Echelle Spectrograph on the 2.5 m Irenee Du Pont Telescope. All observations were taken with a 1$\farcs$0 slit, resulting in a resolution of $\lambda$/\Delta$$\lambda $\approx$ 32,000 covering the 4000–9000 Å wavelength range. Standard IRAF echelle routines were used to reduce the data.

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3 Analysis

3.1 Spectral Types

Spectral types are taken from the literature, with references given in Table 2. For those objects without an available spectral type, we measure the type using the TiO5 index defined in Reid et al. (1995). The spectral type distribution of the entire sample is shown in Figure 1.

3.2 Radial Velocities

One of the main objectives of this work is to measure radial velocities for potentially young, nearby, low mass stars. For each of our high-resolution spectra, we isolate the reddest orders ($\gtrsim$7000 Å) for radial velocity measurements as that is where the signal to noise ratio (S/N) is highest for low mass stars. Each order was cross-correlated with radial velocity standards of similar spectral type using the fxcor routine from IRAF. Radial velocities were measured by finding the Gaussian peak of the cross-correlation function in each order. We average the radial velocities of all orders to determine a final value, and use the standard deviation of the radial velocity from each order as the measurement uncertainty. All measured radial velocities are given in Table 1. The median uncertainty for our radial velocity measurements is $\sim$0.7 km s*-1*. Objects found to be likely spectroscopic binaries via multiple resolved peaks in the resulting cross-correlations functions are noted in Table 1 and will be discussed further in a future publication.

In Table 2, we combine our radial velocity measurements with astrometry from Gaia DR2 (Gaia Collaboration et al., 2018) to calculate full XYZUVW kinematics for each object in our sample. For objects with more than one radial velocity measurement, we take the weighted average. For some objects, astrometry from Gaia DR2 was unavailable. In these instances, we filled in astrometry from other sources, as described in the Table 2 astrometry notes.

\startlongtable

We searched the literature for previously measured radial velocities for our targets. We found 540 individual radial velocity measurements for 241 of the targets in our sample. Thus, 91 of our targets have radial velocities presented for the first time. In many cases where a previously measured radial velocity is available, our measurement is of significantly higher precision. All previously measured radial velocities are given in Table 3. Excluding spectroscopic binaries noted in Table 1, the median $\sigma$ difference (difference divided by combined uncertainty) for all previously measured radial velocities compared to our measurements is 2.45$\sigma$. Note that cases with large radial velocity differences may not necessarily indicate an erroneous measurement, as they could instead be evidence of spectroscopic binarity.

Three catalogs constituted more than half of the previously reported radial velocities of our targets; Malo et al. (2014), the 5th data release of the Radial Velocity Experiment (RAVE; Kunder et al. 2017), and Gaia DR2 (Gaia Collaboration et al., 2018). The number of objects in common with Gaia DR2 are 99, with a median difference of 2.06$\sigma$. The number of objects that also have radial velocities in RAVE is 93, with a median difference of 3.91$\sigma$. The number of objects in common with Malo et al. (2014) is 74, with a median difference of 0.58$\sigma$. A comparison of our measured radial velocities with those from Gaia DR2, RAVE, and Malo et al. (2014) is shown in Figure 2. The median radial velocity uncertainties for Gaia DR2, RAVE, and Malo et al. (2014) measurements are 1.8 km s*-1*, 3.9 km s*-1*, and 0.5 km s*-1*, respectively.

3.3 Age Diagnostics

For each object in our sample, we measure H$\alpha$ and Li $\lambda$6707 equivalent widths and report the values in Table 2. The detection limit for Li equivalent widths is taken to be 0.05 Å following Shkolnik et al. (2009). Because we aimed for the S/N for each observed spectrum, and the resolutions are similar for each spectrograph, this limit applies to all observations. We also gathered X-ray data from ROSAT (Truemper, 1982) using the Second ROSAT all-sky survey (2RXS; Boller et al. 2016). Each detection was converted to an X-ray flux using equations (5) and (6) from Riaz et al. (2006), which was then converted to an X-ray luminosity with the following equation:

[TABLE]

which comes from NASA’s High Energy Astrophysics Science Archive Research Center (HEASARC)111https://heasarc.gsfc.nasa.gov/W3Browse/all/rassdsstar.html.

We also include FUV and NUV photometry from the Galaxy Evolution Explorer (GALEX), as young ($<$300 Myr) moving group members have been shown to have higher UV flux levels than field objects in the same mass range (e.g., Rodriguez et al. 2011, Shkolnik et al. 2011, Schneider & Shkolnik 2018).

We also provide Gaia DR2 photometry for the entire sample in Table 2, which is used to construct color-magnitude diagrams in subsequent sections. 2MASS JHK photometry is also provided for convenience.

4 Discussion

4.1 Objects with Ongoing Accretion

Strong H$\alpha$ emission can signify ongoing accretion on low-mass stars. We identify objects that are potentially accreting using the empirical accretion boundary for H$\alpha$ equivalent widths presented in Barrado y Navascués & Martín (2003). Note that the empirical relation in Barrado y Navascués & Martín (2003) is only applicable for objects with spectral types earlier than M5.5. Figure 3 shows the H$\alpha$ measurements for our entire sample sorted by spectral type. Only one object in our sample with a spectral type later than M5.5 shows strong H$\alpha$ absorption ($\geq$ -20 Å), the well known flare star DG Phe. Five objects are noted to be above the accretion boundary in the spectral type range K5 to M5.5. However, previous work has shown that the boundary defined in Barrado y Navascués & Martín (2003) does not exclusively identify accretors, as several well known non-accreting flare stars lie above the curve (Shkolnik et al., 2009). Therefore, for any object lying above the Barrado y Navascués & Martín (2003) boundary, we also evaluate the 10%-width defined in White & Basri (2003), which has been shown to better identify accreting objects. White & Basri (2003) define an accretion boundary for the 10%-width of $>$200 km s*-1* for non-optically veiled stars.

Of the five objects above the Barrado y Navascués & Martín (2003) curve, one object is the known accretor and $\beta$ Pic member V4046 Sgr (2MASS J18141047$-$3247344), with a spectral type of K5+K7 for which we measure a 10%-width of 447 km s*-1*. 2MASS 05082729$-$2101444 is a second $\beta$ Pic member, confirmed in Section 4.2.3, with a 10%-width of 197 km s*-1*, right at the White & Basri (2003) accretion boundary. 2MASS 05425587$-$0718382 (aka V* V909 Ori) is another well-known flare star just beyond the accretion boundary in Figure 3, and with a 10%-width of 241 km s*-1*, is likely accreting. This object is rejected as a potential Columba member in Section 4.2.6., though is likely young based on its position in color-magnitude diagrams and its H$\alpha$ emission. 2MASS 08440914-7833457 is a member of the $\sim$11 Myr old $\eta$ Cha cluster in Section 4.2.8, and is accreting, with a 10%-width of 212 km s*-1*. 2MASS 06002304$-$4401217 is an object reclassified as a $\sim$45 Myr old member of the Tucana-Horologium Association (see Section 4.2.10), though has a 10%-width of only 121 km s*-1*, and is thus not likely to be accreting.

4.2 Co-Moving Companions

Co-moving systems are valuable benchmarks for testing formation and evolutionary models because the objects in such systems share many of the same physical parameters, such as age, distance, and composition. The astrometric data from Gaia DR2 allows for a search for co-moving companions to each object in our sample. For each object, we chose a search radius corresponding to 0.1 pc separation at the object’s distance. This separation corresponds to a $>$50% survivability rate according to Weinberg et al. (1987). However, we note that co-moving systems with much larger separations are known to exist (e.g., Oh et al. 2017) and thus our search radius can be thought of as conservative. The average distance for objects in our sample is $\sim$34 pc, which would correspond to a search radius of $\sim$10′. Using the appropriate search radii, we investigated for objects with parallaxes within 0.1 pc of each object in our sample.

To ensure objects are co-moving, we first verify that any potential companions have similar parallaxes by requiring \Delta$$D - 3$\sigma$D $<$ 1 pc (e.g., Hollands et al. 2018), where \Delta$$D is the difference between measured distances, and $\sigma$D is the combined distance uncertainty for the target and potential companion. We then ensure similar proper motions by requiring \Delta$$\mu/$\mu$ $<$ 0.21, where \Delta$$\mu $\equiv$ (\Delta$$\mu_{\alpha} + \Delta$$\mu_{\delta})${}^{\text@frac{1}{2}}$ (e.g., Dupuy & Liu 2012). Note that this proper motion condition for companionship is valid for proper motions greater than $\sim$150 mas yr*-1*. We relax this condition to \Delta$$\mu/$\mu$ $<$ 0.31 for smaller proper motions. Only two systems required this lower proper motion threshold (systems 9 and 29 in Table 4).

A total of 69 co-moving systems were found, and are listed in Table 4. Systems containing multiple objects in our target list are only listed once. Sixty-three of the sixty-nine systems contain a single co-moving companion, while the remaining 6 systems contain 3 or more components. Figure 4 shows color-magnitude diagrams (CMDs) of all companions using Gaia DR2 parallaxes and photometry. The panels show G, GBP, and GRP photometry($\lambda$0 = 673, 532, and 797 nm, respectively; Jordi et al. 2010). The figure shows that the spectral types of the companions found to objects in our sample are a mix of earlier and later spectral types, along with a handful of white dwarfs.

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4.3 Moving Group Membership

We evaluate each object for potential moving group membership using the BANYAN $\Sigma$ tool (Gagné et al., 2018a), which evaluates the membership probabilities by comparing positions to known members of different groups using a Bayesian classifier. BANYAN $\Sigma$ considers all kinematic information (position, proper motion, parallax, and radial velocity) to compare 6-dimensional XYZUVW coordinates to known groups using multivariate Gaussians. While we evaluate membership in all groups included in BANYAN $\Sigma$, potential matches from our sample were found for 10 groups listed in Table 5. Any object with a BANYAN $\Sigma$ probability of $>$1% for a particular group was investigated for potential membership. The TW Hya and Scorpius-Centaurus Associations are part of a larger, targeted search for new members by our research group, and will be discussed in a forthcoming separate study.

Note that a kinematic match to a particular group using BANYAN $\Sigma$ does not guarantee membership because kinematic interlopers with different ages are possible. For all kinematic matches, we also evaluate membership using all available age information gathered in Table 4 to ensure consistency with the age of any matching group. Note that any objects in our list that are already included in the bonafide members of BANYAN $\Sigma$ are not discussed further. Table 5 summarizes the number of new, confirmed, and rejected members found for all groups. Table 6 provides age and kinematic information for new, confirmed, and reassigned moving group and association members, while Table 7 provides information for all rejected moving group and association members. Notes for each group including comments on individual sources are presented in the following sections.