SDSS J100711.74+193056.2: A Candidate Common Motion Substellar Companion to the Nearest B-type Star Regulus
The L9 dwarf SDSS J100711.74+193056.2 is situated 7 $\mathop{.}\limits^{^\circ }$ 5 north of the nearest B-type star Regulus ( d = 24.3 ± 0.2 pc), part of a stellar quadruplet. The object is at similar distance ( d = 21.9 ± 1.0 pc) as Regulus, with a 3D separation of $3.{9}_{-0.5}^{+0.6}$ pc (~1....
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IOP Publishing
2025-01-01
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| Series: | The Astronomical Journal |
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| Online Access: | https://doi.org/10.3847/1538-3881/ad991b |
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| author | Eric E. Mamajek Adam J. Burgasser |
| author_facet | Eric E. Mamajek Adam J. Burgasser |
| author_sort | Eric E. Mamajek |
| collection | DOAJ |
| description | The L9 dwarf SDSS J100711.74+193056.2 is situated 7 $\mathop{.}\limits^{^\circ }$ 5 north of the nearest B-type star Regulus ( d = 24.3 ± 0.2 pc), part of a stellar quadruplet. The object is at similar distance ( d = 21.9 ± 1.0 pc) as Regulus, with a 3D separation of $3.{9}_{-0.5}^{+0.6}$ pc (~1.6 tidal radii from Regulus), and shares tangential motion within 2 km s ^−1 , hinting at a physical connection. Near-infrared spectroscopy with Keck/NIRES finds that SDSS J100711.74+193056.2 also has a comparable radial velocity as Regulus A and B, a metallicity similar to Regulus B, and a spectral morphology consistent with the estimated 1–2 Gyr total age of Regulus's close pre-white-dwarf companion. Taken together, these observations indicate that SDSS J100711.74+193056.2 is a very widely separated and potentially physically bound companion to Regulus, with a binding energy and mass ratio comparable to other wide star-brown dwarf systems. It joins a growing list of brown dwarfs at the L-dwarf/T-dwarf transition with independent constraints on physical properties such as age and metallicity. |
| format | Article |
| id | doaj-art-e4f077c3fe6b44d89674afe50975850a |
| institution | DOAJ |
| issn | 1538-3881 |
| language | English |
| publishDate | 2025-01-01 |
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| series | The Astronomical Journal |
| spelling | doaj-art-e4f077c3fe6b44d89674afe50975850a2025-08-20T03:17:39ZengIOP PublishingThe Astronomical Journal1538-38812025-01-0116927710.3847/1538-3881/ad991bSDSS J100711.74+193056.2: A Candidate Common Motion Substellar Companion to the Nearest B-type Star RegulusEric E. Mamajek0https://orcid.org/0000-0003-2008-1488Adam J. Burgasser1https://orcid.org/0000-0002-6523-9536Jet Propulsion Laboratory, California Institute of Technology , 4800 Oak Grove Dr., Pasadena, CA 91109, USA ; mamajek@jpl.nasa.govDepartment of Astronomy & Astrophysics , UC San Diego, 9500 Gilman Dr., La Jolla, CA 92093, USA ; aburgasser@mail.ucsd.eduThe L9 dwarf SDSS J100711.74+193056.2 is situated 7 $\mathop{.}\limits^{^\circ }$ 5 north of the nearest B-type star Regulus ( d = 24.3 ± 0.2 pc), part of a stellar quadruplet. The object is at similar distance ( d = 21.9 ± 1.0 pc) as Regulus, with a 3D separation of $3.{9}_{-0.5}^{+0.6}$ pc (~1.6 tidal radii from Regulus), and shares tangential motion within 2 km s ^−1 , hinting at a physical connection. Near-infrared spectroscopy with Keck/NIRES finds that SDSS J100711.74+193056.2 also has a comparable radial velocity as Regulus A and B, a metallicity similar to Regulus B, and a spectral morphology consistent with the estimated 1–2 Gyr total age of Regulus's close pre-white-dwarf companion. Taken together, these observations indicate that SDSS J100711.74+193056.2 is a very widely separated and potentially physically bound companion to Regulus, with a binding energy and mass ratio comparable to other wide star-brown dwarf systems. It joins a growing list of brown dwarfs at the L-dwarf/T-dwarf transition with independent constraints on physical properties such as age and metallicity.https://doi.org/10.3847/1538-3881/ad991bL dwarfsMultiple starsT dwarfsWide binary stars |
| spellingShingle | Eric E. Mamajek Adam J. Burgasser SDSS J100711.74+193056.2: A Candidate Common Motion Substellar Companion to the Nearest B-type Star Regulus The Astronomical Journal L dwarfs Multiple stars T dwarfs Wide binary stars |
| title | SDSS J100711.74+193056.2: A Candidate Common Motion Substellar Companion to the Nearest B-type Star Regulus |
| title_full | SDSS J100711.74+193056.2: A Candidate Common Motion Substellar Companion to the Nearest B-type Star Regulus |
| title_fullStr | SDSS J100711.74+193056.2: A Candidate Common Motion Substellar Companion to the Nearest B-type Star Regulus |
| title_full_unstemmed | SDSS J100711.74+193056.2: A Candidate Common Motion Substellar Companion to the Nearest B-type Star Regulus |
| title_short | SDSS J100711.74+193056.2: A Candidate Common Motion Substellar Companion to the Nearest B-type Star Regulus |
| title_sort | sdss j100711 74 193056 2 a candidate common motion substellar companion to the nearest b type star regulus |
| topic | L dwarfs Multiple stars T dwarfs Wide binary stars |
| url | https://doi.org/10.3847/1538-3881/ad991b |
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