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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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