SCExAO and GPI $YJH$ Band Photometry and Integral Field Spectroscopy of the Young Brown Dwarf Companion to HD 1160

TL;DR

This study provides detailed photometry and spectroscopy of the young brown dwarf HD 1160 B, revealing its physical properties and discussing its age and mass estimates within the system, contributing to understanding substellar companions.

Contribution

First detailed $YJH$ band photometry and spectroscopy of HD 1160 B, with atmospheric modeling and age estimation, improving characterization of young substellar companions.

Findings

HD 1160 B has a spectral type of M5.5+1.0/-0.5.

Effective temperature of 3000-3100 K for HD 1160 B.

Age estimates range from 20 to 125 Myr, with mass near the hydrogen-burning limit.

Abstract

We present high signal-to-noise ratio, precise $YJH$ photometry and $Y$ band (\gpiwave~$\mu$m) spectroscopy of HD 1160 B, a young substellar companion discovered from the Gemini NICI Planet Finding Campaign, using the Subaru Coronagraphic Extreme Adaptive Optics instrument and the Gemini Planet Imager. HD 1160 B has typical mid-M dwarf-like infrared colors and a spectral type of M5.5$^{+1.0}_{-0.5}$, where the blue edge of our $Y$ band spectrum rules out earlier spectral types. Atmospheric modeling suggests HD 1160 B having an effective temperature of 3000--3100 $K$, a surface gravity of log $g$ = 4--4.5, a radius of~\bestfitradius~$R_{\rm J}$, and a luminosity of log $L$/$L_{\odot} = -2.76 \pm 0.05$. Neither the primary's Hertzspring-Russell diagram position nor atmospheric modeling of HD 1160 B show evidence for a sub-solar metallicity. The interpretation of the HD 1160 B depends on which stellar system components are used to estimate an age. Considering HD 1160 A, B and C jointly, we derive an age of 80--125 Myr, implying that HD 1160 B straddles the hydrogen-burning limit (70--90 $M_{\rm J}$). If we consider HD 1160 A alone, younger ages (20--125 Myr) and a brown dwarf-like mass (35--90 $M_{\rm J}$) are possible. Interferometric measurements of the primary, a precise GAIA parallax, and moderate resolution spectroscopy can better constrain the system's age and how HD 1160 B fits within the context of (sub)stellar evolution.