Characterization of the Host Binary of the Directly Imaged Exoplanet HD 143811 AB b

Abstract

Abstract HD 143811 AB is the host star to the directly imaged planet HD 143811 AB b, which was recently discovered using data from the Gemini Planet Imager and Keck NIRC2. A member of the Sco-Cen star-forming region with an age of 13 ± 4 Myr, HD 143811 AB is somewhat rare among hosts of directly imaged planets, as it is a close stellar binary, with an ∼18-day period. Accurate values for the orbital and stellar parameters of this binary are needed to understand the formation and evolutionary history of the planet in orbit. We utilize archival high-resolution spectroscopy from FEROS on the MPG/ESO 2.2 m telescope to fit the orbit of the binary, and we combine with unresolved photometry to derive the basic stellar properties of the system. From the orbit, we derive precise values of orbital period of 18.59090 ± 0.00007 days and mass ratio of 0.886 ± 0.003. When combined with stellar evolutionary models, we find masses of both components of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mi>M</mml:mi> <mml:mi mathvariant="normal">A</mml:mi> </mml:msub> <mml:mo>=</mml:mo> <mml:mn>1.3</mml:mn> <mml:msubsup> <mml:mn>0</mml:mn> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.05</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.03</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> M ⊙ and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mi>M</mml:mi> <mml:mi mathvariant="normal">B</mml:mi> </mml:msub> <mml:mo>=</mml:mo> <mml:mn>1.1</mml:mn> <mml:msubsup> <mml:mn>5</mml:mn> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.04</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.03</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> M ⊙ . While the current data are consistent with the planet and stellar orbits being coplanar, the 3D orientations of both systems are currently poorly constrained, with additional observations required to more rigorously test for coplanarity.

Affiliated Institutions

• University of California, Berkeley US
• Western University CA
• Amherst College US
• University of California, Los Angeles US
• Jet Propulsion Laboratory US
• Space Telescope Science Institute US
• European Southern Observatory CL
• California Institute of Technology US
• American Museum of Natural History US
• United States Naval Observatory US
• Planetary Science Institute US
• Infrared Processing and Analysis Center US
• University of Victoria CA
• University of Georgia US
• Centre National de la Recherche Scientifique FR
• Université Grenoble Alpes FR
• Northwestern University US
• Arizona State University US
• University of California, Santa Cruz US
• University of Arizona US
• Deleted Institution
• Lawrence Livermore National Laboratory US
• Observatoire de la Côte d’Azur FR
• Herzberg Institute of Astrophysics CA
• New Mexico State University US
• University of California, San Diego US
• Smith College US
• Université de Montréal CA
• University of California, Santa Barbara US
• Foundation for Research and Technology Hellas GR
• Cornell University US
• George Mason University US
• Durham University GB
• University of Hawaii System US
• Université Bourgogne Franche-Comté FR
• University of Notre Dame US
• Search for Extraterrestrial Intelligence US

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