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2MASS J05325346 8246465

Coordinates: Sky map 05h 32m 53.46s, 82° 46′ 46.5″
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2MASS J05325346 8246465

2MASS J0532 8246
Credit: SDSS
Observation data
Epoch J2000      Equinox J2000
Constellation Camelopardalis
Right ascension 05h 32m 54.4345s[1]
Declination 82° 46′ 45.161″[1]
Characteristics
Spectral type esdL8:[2]
Astrometry
Radial velocity (Rv)−172±1[3] km/s
Proper motion (μ) RA: 2038.794(561) mas/yr[1]
Dec.: −1662.958(484) mas/yr[1]
Parallax (π)40.7097 ± 0.4597 mas[1]
Distance80.1 ± 0.9 ly
(24.6 ± 0.3 pc)
Details
Mass0.077–0.085[4] M☉
Temperature1600[5] K
Metallicity [Fe/H]−1.6[5] dex
Rotational velocity (v sin i)65 ±15[3] km/s
Age~10[5] Gyr
Other designations
2MASS J05325346 8246465,[6]
2MASS 0532 8246
Database references
SIMBADdata

2MASS J05325346 8246465 (abbreviated 2MASS J0532 8246) is possibly the first brown dwarf observed in the galactic halo of the Milky Way, and the first known substellar subdwarf star.[7][8] It was discovered from Two Micron All-Sky Survey data, and verified by observations at Palomar Observatory and W. M. Keck Observatory.[8] It has a low metallicity, which indicates it is an old star.[8]

The mass and temperature of 2MASS 0532 8246 makes it a rare object in stellar-substellar gap between conventional stars and brown dwarfs.[9] It produces roughly half of its luminosity from hydrogen fusion.[5] Such "gap" objects, covering a narrow range of masses but a wide range of temperatures, and powered by unsteady hydrogen fusion, are exotic but expected to be more common among low-metallicity objects like 2MASS J05325346 8246465.[10]

In 2008 it was discovered that this object is on a retrograde galactic orbit that is both eccentric and extends well away from the plane, making this object a member of the galactic halo.[11] In 2024 this object was identified as a possible member of the Thamnos populations, together with the T subdwarf CWISE J113010.07 313944.7.[2] Thamnos has two substructures called Thamnos 1 and Thamnos 2, both were identified in 2019 from Gaia data.[12] Thamnos is likely the remnant of a dwarf galaxy that was accreted into the Milky Way and consists of metal-poor stars that formed between 8 and 12.89 billion years.[13]

References

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  1. ^ a b c d Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  2. ^ a b Burgasser, Adam J.; Schneider, Adam C.; Meisner, Aaron M.; Caselden, Dan; Hsu, Chih-Chun; Gerasimov, Roman; Aganze, Christian; Softich, Emma; Karpoor, Preethi; Theissen, Christopher A.; Brooks, Hunter; Bickle, Thomas P.; Gagné, Jonathan; Artigau, Étienne; Marsset, Michaël; Rothermich, Austin; Faherty, Jacqueline K.; Kirkpatrick, J. Davy; Kuchner, Marc J.; Andersen, Nikolaj Stevnbak; Beaulieu, Paul; Colin, Guillaume; Gantier, Jean Marc; Gramaize, Leopold; Hamlet, Les; Hinckley, Ken; Kabatnik, Martin; Kiwy, Frank; Martin, David W.; Massat, Diego H.; Pendrill, William; Sainio, Arttu; Schümann, Jörg; Thévenot, Melina; Walla, Jim; Wędracki, Zbigniew; the Backyard Worlds: Planet 9 Collaboration (2 Nov 2024). "New Cold Subdwarf Discoveries from Backyard Worlds and a Metallicity Classification System for T Subdwarfs". arXiv:2411.01378 [astro-ph].{{cite arXiv}}: CS1 maint: numeric names: authors list (link)
  3. ^ a b Reiners, A.; Basri, G. (2006-03-01). "The First High-Resolution Spectra of 1.3 L Subdwarfs". The Astronomical Journal. 131: 1806–1815. arXiv:astro-ph/0512130. Bibcode:2006AJ....131.1806R. doi:10.1086/500298. ISSN 0004-6256.
  4. ^ Burgasser, Adam J.; Kirkpatrick, J. Davy; Burrows, Adam; Liebert, James; Reid, I. Neill; Gizis, John E.; McGovern, Mark R.; Prato, L.; McLean, Ian S. (2003). "The First Substellar Subdwarf? Discovery of a Metal-poor L Dwarf with Halo Kinematics". The Astrophysical Journal. 592 (2): 1186–1192. arXiv:astro-ph/0304174. Bibcode:2003ApJ...592.1186B. doi:10.1086/375813. S2CID 11895472.
  5. ^ a b c d Allard, F.; Pinfield, D. J.; Zapatero Osorio, M. R.; Lodieu, N.; Gálvez-Ortiz, M. C.; Burgasser, A. J.; Zhang (张曾华), Z. H. (2019), "Primeval very low-mass stars and brown dwarfs – VI. Population properties of metal-poor degenerate brown dwarfs", Monthly Notices of the Royal Astronomical Society, 486: 1260–1282, arXiv:1903.05536, doi:10.1093/mnras/stz777
  6. ^ "2MASS J05325346 8246465 -- Brown Dwarf (M<0.08solMass)". SIMBAD. Centre de Données astronomiques de Strasbourg. Retrieved 2018-12-04.
  7. ^ Faherty, Jacqueline K.; Burgasser, Adam J.; Walter, Frederick M.; Van der Bliek, Nicole; Shara, Michael M.; Cruz, Kelle L.; West, Andrew A.; Vrba, Frederick J.; Anglada-Escud, Guillem (2012). "The Brown Dwarf Kinematics Project (BDKP). III. Parallaxes for 70 Ultracool Dwarfs". The Astrophysical Journal. 752 (1): 56. arXiv:1203.5543. Bibcode:2012ApJ...752...56F. doi:10.1088/0004-637X/752/1/56. S2CID 18160586.
  8. ^ a b c Burgasser, Adam J.; et al. (2003). "The First Substellar Subdwarf? Discovery of a Metal-Poor L Dwarf with Halo Kinematics". The Astrophysical Journal. 592 (2): 1186–1192. arXiv:astro-ph/0304174. Bibcode:2003ApJ...592.1186B. doi:10.1086/375813. S2CID 11895472.
  9. ^ Zhang 张曾华, Z. H.; Homeier, D.; Pinfield, D. J.; Lodieu, N.; Jones, H. R. A.; Allard, F.; Pavlenko, Ya. V. (2017), "Primeval very low-mass stars and brown dwarfs – II. The most metal-poor substellar object", Monthly Notices of the Royal Astronomical Society, 468 (1): 261–271, arXiv:1702.02001, Bibcode:2017MNRAS.468..261Z, doi:10.1093/mnras/stx350, S2CID 54847595
  10. ^ Schneider, Adam C.; Burgasser, Adam J.; Gerasimov, Roman; Marocco, Federico; Gagné, Jonathan; Goodman, Sam; Beaulieu, Paul; Pendrill, William; Rothermich, Austin; Sainio, Arttu; Kuchner, Marc J.; Caselden, Dan; Meisner, Aaron M.; Faherty, Jacqueline K.; Mamajek, Eric E.; Hsu, Chih-Chun; Greco, Jennifer J.; Cushing, Michael C.; Kirkpatrick, J. Davy; Bardalez-Gagliuffi, Daniella; Logsdon, Sarah E.; Allers, Katelyn; Debes, John H. (2020), "WISEA J041451.67–585456.7 and WISEA J181006.18–101000.5: The First Extreme T-type Subdwarfs?", The Astrophysical Journal, 898 (1): 77, arXiv:2007.03836, Bibcode:2020ApJ...898...77S, doi:10.3847/1538-4357/ab9a40, S2CID 220403370
  11. ^ Burgasser, Adam J.; Vrba, Frederick J.; Lépine, Sébastien; Munn, Jeffrey A.; Luginbuhl, Christian B.; Henden, Arne A.; Guetter, Harry H.; Canzian, Blaise C. (2008-01-01). "Parallax and Luminosity Measurements of an L Subdwarf". The Astrophysical Journal. 672: 1159–1166. arXiv:0709.1373. Bibcode:2008ApJ...672.1159B. doi:10.1086/523810. ISSN 0004-637X.
  12. ^ Koppelman, Helmer H.; Helmi, Amina; Massari, Davide; Price-Whelan, Adrian M.; Starkenburg, Tjitske K. (2019-11-01). "Multiple retrograde substructures in the Galactic halo: A shattered view of Galactic history". Astronomy and Astrophysics. 631: L9. arXiv:1909.08924. Bibcode:2019A&A...631L...9K. doi:10.1051/0004-6361/201936738. ISSN 0004-6361.
  13. ^ Deepak (2024-12-01). "Stellar substructures in the Galactic disc and halo: Properties, origins, and evolution". Journal of Astrophysics and Astronomy. 45: 25. arXiv:2407.14508. Bibcode:2024JApA...45...25D. doi:10.1007/s12036-024-10011-1. ISSN 0250-6335.
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