Dynamical Masses of Eps Ind B and C: Two Massive Brown Dwarfs at the Edge of the Stellar-Substellar Boundary
| Autor: | Wei-Chun Jao, Maggie A. Thompson, Alan P. Boss, Sergio B. Dieterich, Alycia J. Weinberger, Jonathan Gagné, Tri L. Astraatmadja, Todd J. Henry, Guillem Anglada-Escudé |
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| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
Earth and Planetary Astrophysics (astro-ph.EP)
Physics Brown dwarf FOS: Physical sciences Boundary (topology) Astronomy and Astrophysics Astrophysics Astrometry Edge (geometry) 01 natural sciences 010104 statistics & probability Astrophysics - Solar and Stellar Astrophysics 13. Climate action Space and Planetary Science 0103 physical sciences 0101 mathematics 010303 astronomy & astrophysics Solar and Stellar Astrophysics (astro-ph.SR) Astrophysics - Earth and Planetary Astrophysics |
| Popis: | We report individual dynamical masses for the brown dwarfs Epsilon Indi B and C, which have spectral types of T1.5 and T6, respectively, measured from astrometric orbit mapping. Our measurements are based on a joint analysis of astrometric data from the Carnegie Astrometric Planet Search and the Cerro Tololo Inter-American Observatory Parallax Investigation as well as archival high resolution imaging, and use a Markov Chain Monte Carlo method. We find dynamical masses of 75.0+-0.82 Mjup for the T1.5 B component and 70.1+-0.68 Mjup for the T6 C component. These masses are surprisingly high for substellar objects and challenge our understanding of substellar structure and evolution. We discuss several evolutionary scenarios proposed in the literature and find that while none of them can provide conclusive explanations for the high substellar masses, evolutionary models incorporating lower atmospheric opacities come closer to approximating our results. We discuss the details of our astrometric model, its algorithm implementation, and how we determine parameter values via Markov Chain Monte Carlo Bayesian inference. Submitted to ApJ. Cleared by statistics referee. Incorporates response to science referee. Includes link to MCMC code |
| Databáze: | OpenAIRE |
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