Abstract
Evidence is presented that 2MASS J03202839� 0446358, a late-type dwarf with discrepant optical (M8:) and nearinfrared(L1)spectraltypes,isanas-yetunresolvedstellar/browndwarfbinarywithlate-typeMdwarfandTdwarfcomponents. This conclusion is based on low-resolution, near-infrared spectroscopy that reveals a subtle but distinctive absorption feature at 1.6 � m. The feature, which is also present in the combined light spectrum of the M8.5 + T6 binary SCR 1845� 6357, arises from the combination of FeH absorption from an M8.5 primary and pseudocontinuum flux from a T5 � 1 secondary, as ascertained from binary spectral templates constructed from empirical data. The binary templates provide a far superior match to the overall near-infrared spectral energy distribution of 2MASS J0320� 0446 than any single comparison spectra. Laser guide star adaptive optics (LGS AO) imaging observations, including the first application of LGS AO aperture mask interferometry, fail to resolve a faint companion, restricting the projected separation of the system to less than 8.3 AU at the time of observation. 2MASS J0320� 0446 is the second very low mass binary to be identified from unresolved, low-resolution, near-infrared spectroscopy, a technique that complements traditional high-resolution imaging and spectroscopic methods. Subject headingg binaries: general — stars: fundamental parameters — stars: individual — stars: low-mass, brown dwarfs
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call