2MASS J10274572+0629104: the very short period young M6 dwarf binary system identified in K2 data. Issue 3 (13th April 2019)

• Record Type: Journal Article
• Authors: Paudel, R R; Gizis, J E; Burgasser, A J; Hsu, C
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 486:Issue 3(2019)
• Page Start: 4144
• Page End: 4148
• Publication Date: 2019-04-13
• Subjects: binaries: general -- stars: individual: 2MASS J10274572+0629104 -- stars: low-mass -- stars: rotation; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/stz1067
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: We report the identification of a very low mass new binary system 2MASS J10274572+0629104, based on Kepler K 2 photometry and Gaia DR2 astrometry. It is located at a distance of 90.0 ± 2.9 pc. The K 2 light curve is consistent with a beat pattern of two periodic signals, and using Lomb–Scargle periodogram, we find two rotation periods of 0.2114 ± 0.0002 and 0.2199 ± 0.0003 d. We conclude that these rotation periods arise from two stars with similar spectral types of M6, and have nearly equal luminosity. It is the first ultracool binary system to be identified based on beat patterns in the light curve. Near-infrared spectroscopy yields RV = −9.8 ± 0.6 km s −1, v sin i = 21.5 ± 1.1 km s −1, T eff = 3110 ± 40 K, and log g = 5.2 ± 0.2. The motions are consistent with a young age, as are the rotation periods, but the source does not appear to be part of any known moving group. Furthermore, we detected three strong white light flares in the K 2 light curve, with estimated total (UV/optical/IR) energies of 2.6 × 10 33, 5.0 × 10 33, and 3.5 × 10 33 erg, respectively.