An L 0 dwarf companion in the brown dwarf desert , at 30 AU ⋆
نویسندگان
چکیده
We present the discovery of an L0 companion to the nearby M1.5 dwarf G 239-25, at a projected distance of 31 AU. It is the faintest companion discovered so far in our adaptive optics survey of all known M dwarfs within 12 pc, and it lies at the stellar/substellar limit. Given the assumed age of the primary star, the companion is likely an extremely low mass star. The long orbital period of G 239-25 AB (≈ 100 years) precludes a direct mass determination, but the relatively wide angular separation will allow detailed analyses of its near infrared and visible spectra.
منابع مشابه
Substellar Companions to Main-sequence Stars: No Brown Dwarf Desert at Wide Separations
We use three field L and T dwarfs that were discovered to be wide companions to known stars by the Two Micron All-Sky Survey to derive a preliminary brown dwarf companion frequency. Observed L and T dwarfs indicate that brown dwarfs are not unusually rare as wide ( AU) systems to F–M0 main-sequence stars D 1 1000 ( , ), even though they are rare at close separation ( AU; the “brown dwarf desert...
متن کاملDiscovery of a Tight Brown Dwarf Companion to the Low Mass Star LHS 2397a
Using the adaptive optics system, Hokupa’a, at Gemini-North, we have directly imaged a companion around the UKIRT faint standard M8 star, LHS 2397a (FS 129) at a separation of 2.96 AU. Near-Infrared photometry of the companion has shown it to be an L7.5 brown dwarf and confirmed the spectral type of the primary to be M8. We also derive a substellar mass of the companion of 0.068M⊙, although mas...
متن کاملThe Brown Dwarf Desert at 75–1200 Au
We present results of a comprehensive infrared coronagraphic search for substellar companions to nearby stars. The research consisted of (1) a 178-star survey at Steward and Lick observatories, with optical follow-up from Keck Observatory, capable of detecting companions with masses greater than 30 MJ, and semimajor axes between about 140 to 1200 AU; (2) a 102-star survey using the Keck Telesco...
متن کاملCrossing the Brown Dwarf Desert Using Adaptive Optics : A Very Close L - Dwarf Companion to the Nearby Solar Analog HR 7672
We have found a very faint companion to the active solar analog HR 7672 (HD 190406; GJ 779; 15 Sge). Three epochs of high resolution imaging using adaptive optics (AO) at the Gemini-North and Keck II Telescopes demonstrate that HR 7672B is a common proper motion companion, with a separation of 0. 79 (14 AU) and a 2.16 μm flux ratio of 8.6 mags. Using follow-up K-band spectroscopy from Keck AO+N...
متن کاملMapping the Shores of the Brown Dwarf Desert. I. Upper Scorpius
We present the results of a survey for stellar and substellar companions to 82 young stars in the nearby OB association Upper Scorpius. This survey used nonredundant aperture mask interferometry to achieve typical contrast limits of K 5Y6 at the diffraction limit, revealing 12 new binary companions that lay below the detection limits of traditional high-resolution imaging; we also summarize a c...
متن کامل