The Kappa Andromedae System: New Constraints on the Companion
Draft version June 25, 2018 A Preprint typeset using LTEX style emulateapj v. 5/2/11 THE κ ANDROMEDAE SYSTEM: NEW CONSTRAINTS ON THE COMPANION MASS, SYSTEM AGE & FURTHER MULTIPLICITY Sasha Hinkley1,17, Laurent Pueyo2,18, Jacqueline K. Faherty3, Ben R. Oppenheimer4, Eric E. Mamajek5, Adam L. Kraus6, Emily Rice7,3, Michael J. Ireland 8,9, Trevor David1, Lynne A. Hillenbrand1, Gautam Vasisht10, Eric Cady10, Douglas Brenner4, Aaron Veicht4, Ricky Nilsson4, Neil Zimmerman11, Ian R. Parry12, Charles Beichman13, Richard Dekany14, Jennifer E. Roberts10, Lewis C Roberts Jr.10, Christoph Baranec14, Justin R. Crepp15, Rick Burruss10, J. Kent Wallace10, David King12, Chengxing Zhai10, Thomas Lockhart10, Michael Shao10, Remi´ Soummer2, Anand Sivaramakrishnan2, Louis A. Wilson16 Draft version June 25, 2018 ABSTRACT κ Andromedae is a B9IVn star at 52 pc for which a faint substellar companion separated by 55±2 AU was recently announced. In this work, we present the first spectrum of the companion, “κ And B,” using the Project 1640 high-contrast imaging platform. Comparison of our low-resolution YJH-band spectra to empirical brown dwarf spectra suggests an early-L spectral type. Fitting synthetic spectra from PHOENIX model atmospheres to our observed spectrum allows us to constrain the effective temperature to ∼2000 K, as well as place constraints on the companion surface gravity. Further, we use previously reported log(g) and Teff measurements of the host star to argue that the κ And system has an isochronal age of 220±100 Myr, older than the 30 Myr age reported previously. This interpretation of an older age is corroborated by the photometric properties of κ And B, which appear to be marginally inconsistent with other 10-100 Myr low-gravity L-dwarfs for the spectral type range we derive.
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