\textit{Gaia} EDR3 confirms a red dwarf companion of the nearby F1 star HD 105452 and reveals a new brown dwarf companion of the M4.5 dwarf SCR J1214-2345

TL;DR

Gaia EDR3 data confirmed a red dwarf companion to the nearby F1 star HD 105452 and discovered a new brown dwarf companion to the M4.5 dwarf SCR J1214-2345, demonstrating Gaia's capability in identifying faint stellar companions.

Contribution

This study confirms a previously imaged red dwarf companion and reports the discovery of the faintest brown dwarf companion identified by Gaia to date.

Findings

Confirmed the red dwarf companion of HD 105452 using Gaia data.

Discovered a new brown dwarf companion to SCR J1214-2345 with Gaia.

Provided photometric classification suggesting a T1±3 spectral type for the brown dwarf.

Abstract

There are 88 stars which lack colours, but have measured parallaxes in \textit{Gaia} EDR3 that place them within 20\,pc from the sun. Among them we found two new common parallax and proper motion (CPPM) companions separated from their primaries by about 3\,arcsec. The CPPM companion of a nearby ($d=14.98$\,pc) F1 star, \object{HD 105452 B}, was already imaged with the \textit{Hubble Space Telescope} and is now confirmed with \textit{Gaia} data and photometrically classified by us as M4 dwarf. The other CPPM companion, \object{SCR J1214-2345 B} orbiting an M4.5 dwarf at $d=10.77$\,pc, represents the faintest brown dwarf discovery made by \textit{Gaia} so far. It was also imaged by the VISTA Hemisphere Survey and partly detected in the near-infrared. Our photometric classification led to an uncertain spectal type of T1$\pm$3 and needs to be confirmed by spectroscopic follow-up.