2020ApJ...905L..14F -
Astrophys. J., 905, L14-L14 (2020/December-3)
A wide planetary-mass companion to a young low-mass brown dwarf in Ophiuchus.
FONTANIVE C., ALLERS K.N., PANTOJA B., BILLER B., DUBBER S., ZHANG Z., DUPUY T., LIU M.C. and ALBERT L.
Abstract (from CDS):
We present the discovery of a planetary-mass companion to CFHTWIR-Oph 98, a low-mass brown dwarf member of the young Ophiuchus star-forming region, with a wide 200 au separation (1.''46). The companion was identified using Hubble Space Telescope images, and confirmed to share common proper motion with the primary using archival and new ground-based observations. Based on the very low probability of the components being unrelated Ophiuchus members, we conclude that Oph 98 AB forms a binary system. From our multiband photometry, we constrain the primary to be an M9-L1 dwarf, and the faint companion to have an L2-L6 spectral type. For a median age of 3 Myr for Ophiuchus, fits of evolutionary models to measured luminosities yield masses of 15.4 ± 0.8 MJup for Oph 98 A and 7.8 ± 0.8 MJup for Oph 98 B, with respective effective temperatures of 2320 ± 40 K and 1800 ± 40 K. For possible system ages of 1-7 Myr, masses could range from 9.6-18.4 MJup for the primary, and from 4.1-11.6 MJup for the secondary. The low component masses and very large separation make this binary the lowest binding energy system imaged to date, indicating that the outcome of low-mass star formation can result in such extreme, weakly bound systems. With such a young age, Oph 98 AB extends the growing population of young free-floating planetary-mass objects, offering a new benchmark to refine formation theories at the lowest masses.
Abstract Copyright:
© 2020. The American Astronomical Society. All rights reserved.
Journal keyword(s):
Brown dwarfs - Binary stars
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Objects in title, abstract, text, figures, and all or part of small table(s) being processed in SIMBAD.
Simbad objects:
20
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