Orbital and Atmospheric Characterization of the 1RXS J034231.8+121622 System using High-resolution Spectroscopy Confirms that the Companion is a Low-mass Star
Do Ó, Clarissa R.; Fitzgerald, Michael P.; López, Ronald A.; Skemer, Andrew; Barman, Travis S.; Do, Tuan; Thompson, William; Jovanovic, Nemanja; Wang, Jason J.; Mawet, Dimitri; Inglis, Julie; Blunt, Sarah; Blake, Geoffrey A.; Wallace, J. Kent; Xuan, Jerry W.; Hsu, Chih-Chun; Baker, Ashley; Bartos, Randall; Calvin, Benjamin; Cetre, Sylvain; Delorme, Jacques-Robert; Doppmann, Greg; Echeverri, Daniel; Finnerty, Luke; Liberman, Joshua; Morris, Evan; Pezzato, Jacklyn; Sappey, Ben; Schofield, Tobias; Wang, Ji; Ruffio, Jean-Baptiste; Konopacky, Quinn M.; Theissen, Christopher A.; Martinez, Gregory; O'Neil, Kelly K.; Nguyen, Jayke S.
United States, Canada
Abstract
The 1RXS J034231.8+121622 system consists of an M dwarf primary and a directly imaged low-mass stellar companion. We use high-resolution spectroscopic data from Keck/KPIC to estimate the objects' atmospheric parameters and radial velocities (RVs). Using PHOENIX stellar models, we find that the primary has a temperature of 3460 ± 50 K and a metallicity of 0.16 ± 0.04, while the secondary has a temperature of 2510 ± 50 K and a metallicity of ${0.13}_{-0.11}^{+0.12}$ . Recent work suggests this system is associated with the Hyades, giving it an older age than previous estimates. Both metallicities agree with current Hyades [Fe/H] measurements (0.11–0.21). Using stellar evolutionary models, we obtain significantly higher masses for the objects, 0.30 ± 0.15 M ⊙ and 0.08 ± 0.01 M ⊙ (84 ± 11 M Jup), respectively. Using the RVs and a new astrometry point from Keck/NIRC2, we find that the system is likely an edge-on, moderately eccentric ( ${0.41}_{-0.08}^{+0.27}$ ) configuration. We also estimate the C/O ratio of both objects using custom grid models, obtaining 0.42 ± 0.10 (primary) and 0.55 ± 0.10 (companion). From these results, we confirm that this system most likely went through a binary star formation process in the Hyades. The significant changes in this system's parameters since its discovery highlight the importance of high-resolution spectroscopy for both orbital and atmospheric characterization of directly imaged companions.