2MASS J20261584-2943124: An Unresolved L0.5 T6 Spectral Binary - Astrophysics > Solar and Stellar AstrophysicsReport as inadecuate




2MASS J20261584-2943124: An Unresolved L0.5 T6 Spectral Binary - Astrophysics > Solar and Stellar Astrophysics - Download this document for free, or read online. Document in PDF available to download.

Abstract: We identify the L dwarf 2MASS J20261584-2943124 as an unresolved spectralbinary, based on low-resolution, near-infrared spectroscopy from IRTF-SpeX. Thedata reveal a peculiar absorption feature at 1.6 microns, previously noted inthe spectra of other very low-mass spectral binaries, which likely arises fromoverlapping FeH and CH4 absorption bands in the blended light of an L dwarf-Tdwarf pair. Spectral template matching analysis indicates component types ofL0.5 and T6, with relative brightness Delta H = 4.2+-0.6. Laser guide staradaptive optics imaging observations with Keck-NIRC2 fail to resolve thesource, indicating a maximum separation at the observing epoch of 0.25 arcsec,or a projected separation of 9 AU assuming a distance of 36+-5 pc. With an agethat is likely to be relatively older >5 Gyr based on the system-s large vtanand mass ratio arguments, the relative motion of the potentially -massive-0.06-0.08 Msun components of 2MASS J2026-2943 may be detectable throughradial velocity variations, like its earlier-type counterpart 2MASSJ03202839-0446358 M8+T5, providing dynamical mass measurements that span thehydrogen burning limit.



Author: Christopher R. Gelino IPAC, Adam J. Burgasser CASS-UCSD

Source: https://arxiv.org/



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