T dwarf

An object with the spectral type T (also called T dwarf or methane brown dwarf)[1] is either a brown dwarf[2] or young free-floating planetary-mass object.[3] An directly imaged exoplanet with a young age can also be a T-dwarf.[4] T dwarfs are colder than L dwarfs,[1] but warmer than Y dwarfs.[5]

Prototype Gliese 229B

[edit]
Main article: Gliese 229
Hubble image of Gliese 229B

The first T-dwarf discovered was Gliese 229B, which was discovered in 1995.[6] This object had a temperature below 1000 K and showed methane (CH4), water vapor (H2O) and carbon monoxide (CO) in its spectrum. In the upper atmosphere CO is converted into CH4 and H2O, while the opposite is true for the hotter lower atmosphere.[7][8][9] It also showed absorption due to caesium (Cs), but absorption features commonly found in M-dwarfs (CaH, FeH, TiO, and VO) were missing.[10] Ammonia (NH3) was included in the analysis of the spectrum.[11] Sodium (Na) and potassium (K) are also detected in this T-dwarf.[12] Later work found a dynamical mass of 70 ± 5 MJ for Gliese 229B, which is much higher than the cooling models would suggest.[2] The spectral type is somewhat ambiguous. This is because it shows strong CH4 absorption at 1.3 and 1.6 μm, indicative of a T7 type, but weaker CH4 and H2O features at 1.1, 1.4, 1.9, and 2.2 μm, indicative of a T5-T6 type.[13] It is also suspected that Gliese 229B is a binary, which could explain its high mass and its unusual spectrum.[14] The binarity was confirmed in 2024 with instruments on the Very Large Telescope, which resolved the pair and constrained their orbit to be a tight semi-major axis of about 16 Earth-Moon distances and an orbital period of about 12.1 days. Gliese 229Ba has a mass of about 38 MJ and Gliese 229Bb has a mass of about 34 MJ.[15]

Spectral type T

[edit]
Spectra of mid to late T-dwarfs, showing absorption due to methane, water vapor, CIA hydrogen and potassium

The spectral type "T" was first proposed in 1999 with Gliese 229B as its only representative at the time.[1] Next came the discovery of Gliese 570D,[16] SDSS 1624+00 (first field T-dwarf)[17] and SDSS 1346-00 (second field T-dwarf).[18] These were however mid- to late T-dwarfs and the first early T-dwarfs (SDSS 0837, SDSS 1254, and SDSS 1021) were discovered in data of the Sloan Digital Sky Survey in 2000. These objects show weaker CH4 absorption than previously discovered T-dwarfs.[19] CH4 appears first in the K-band in L8 dwarfs and L- and T-dwarfs are distinguished by the appearance of CH4 in the H-band for T-dwarfs. T-dwarfs show an increasing absorption of H2O and CH4 from T0 to T8. Neutral Na and K features broaden in L- and T-dwarfs and the Na feature increases in depth for L/T-dwarfs with increasing spectral type.[20] One of the coldest T-dwarfs was discovered with UKIDSS, called UGPS 0722-05.[21][22] Researchers used WISE to discover additional late T-dwarfs and the objects of the newly discovered Y-dwarfs. The transition between T- and Y-dwarfs is defined with the help of UGPS 0722-05 as the T9 standard and WISE 1738+2732 as the Y0 standard. Late T and early Y-dwarfs show deep H2O and CH4 absorption features and the transition between T- and Y-dwarfs occurs near 500 K.[5][23] Another important T-dwarf is Luhman 16B, which is the closest T-dwarf. It has a spectral type of T0.5, near the L/T transition. It shows a hint of FeH in the spectrum, which weakens in late L dwarfs, but strengthens in early to mid T-dwarfs due to cloud disruption.[24][25] Observations of T-dwarfs in the near- and mid-infrared with JWST clearly show additional absorption features due to NH3, CH4, H2O, CO and carbon dioxide (CO2).[26] Observations with Gemini showed the first detection of hydrogen sulfide (H2S) and molecular hydrogen (H2) in the T6 dwarf DENIS J081730.0−615520.[27]

Subdwarfs

[edit]
Main article: Subdwarf

Subdwarfs with a T spectral type are known, with 2MASSI J0937347+293142 being the first T-type subdwarf. It shows blue near-infrared colors due to suppression of the 2.1 μm peak, likely caused by enhanced collision induced absorption (CIA) of hydrogen (H2).[28][29] Subdwarfs have a low metallicity and at first only a small sample with moderate low metallicity was known. In 2020 the backyard worlds citizen science project discovered the first extreme subdwarfs of spectral type T, called WISEA 0414−5854 and WISEA 1810−1010. These objects have unusual blue colors, indicative of a lower absorption from CH4.[30] Follow-up observations of WISEA 1810−1010 show that it only shows absorption due to H2O and H2 in the optical and infrared spectra. CH4 is missing completely, which stays in contrast to the definition of T-dwarfs as "methane dwarfs" and WISEA 1810−1010 was instead called a "water vapor dwarf".[31] In 2024 Burgasser et al. introduced a classification system for T subdwarfs, which allows the classification into mild subdwarfs (d/sdT), subdwarfs (sdT) and extreme subdwarfs (esdT). The signature of a low metallicity are a strong collision induce absorption (CIA) of hydrogen molecules, obscured methane and water features, and weak potassium K I absorption. This work also identified three brown dwarfs that are candidate members of stellar streams. Future works with JWST, Euclid, Rubin and Roman will increase the sample of T subdwarfs to thousands.[32] JWST has already discovered the first distant T subdwarfs such as UNCOVER-BD-1.[33]

Brown dwarfs

[edit]
Main article: Brown dwarf

Most T-dwarfs are brown dwarfs. Brown dwarfs have a mass lower than the hydrogen burning minimum mass (0.075 M☉ or 78.5 MJ).[34] There are currently 920 objects in the UltracoolSheet with an infrared spectral type of T.[35] The table of ultracool fundamental parameters lists objects with an infrared spectral type of T that have masses between 2 and 58 MJ.[36][37] Additional T-type brown dwarfs that orbit stars or white dwarfs are known and the age of the primary can help to determine the mass of the T-dwarfs.[38][39][40] One of the oldest known T-dwarfs is Wolf 1130C, which is around 10 billion years old.[41]

Planetary-mass objects and exoplanets

[edit]

One of the first objects that was conclusively determined to be a young isolated planetary-mass object with spectral type T was SDSS J1110+0116 (T5.5), which is a member of the 120 Myr old AB Doradus moving group.[42] Another significant discovery is one of the closest planetary-mass objects, called SIMP J013656.5+093347 (T2.5, 12.7 ±1.0 MJ), which is part of the 200 Myr old Carina-Near moving group.[3] This object is also variable with a period of 2.4 hours, likely due to clouds.[43] It also shows radio emission due to aurorae.[44] Additional young T-dwarf candidates are known from other young stellar associations and these objects show red colors compared to field T-dwarfs.[45] Young directly imaged exoplanets and planetary-mass companions sometimes show a T spectral type, such as 51 Eridani b (T4.5-T6).[4]

Clouds and variability

[edit]
Cloud models in early (SIMP J0136+09, 2MASS J2139+02) and a late-type T-dwarf (2MASS J0050–3322)

Two of the most variable brown dwarfs are the T-dwarfs Luhman 16B, showing a variation up to 20%[46] and 2MASS J2139+02, which varies with an amplitude as high as 26%.[47] T-dwarfs, especially young early-type T-dwarfs are often variable. The variability has been connected to the presence of clouds, but other explanations were proposed, such as hot spots and aurorae.[48] These early T-dwarfs are thought to have an iron cloud deck and a patchy silicate cloud layer on top of it. The silicate clouds are thought to dissipate near the L/T transition, resulting into the patchy silicate cloud layer and high amplitude variability for late L and early T dwarfs.[49] The disruption of clouds make deeper layers accessible for observations. These deeper layers are warmer and contain FeH. This explains the reappearance and strengthening of FeH and the blue near-infrared color for early to mid T-dwarfs.[25] Late T-dwarfs should also have cloud layers made of chromium, potassium chloride and different sulfides. These cloud layers are thin and exist above the silicate clouds.[49] One late T-dwarf that is variable is WISE 0458+6434 (T8.5), which varied with 13% in one epoch.[50]

Magnetic field and aurorae

[edit]

The first T-dwarf detected in radio emission was 2MASS J1047+21 (T6.5), which was discovered with the Arecibo radio telescope.[51] Since then several other T-dwarfs with radio emission were discovered, including the planetary-mass object SIMP J013656.5+093347 (T2.5)[44] and the discovery of the T-dwarf BDR J1750+3809 with the help of radio emission.[52] The coldest T-dwarf with a radio emission is WISEPA J062309.94-045624.6 (T8).[53] Radio emission in T-dwarfs is thought to be generated by an aurora, similar to late L-dwarfs. Additionally H-alpha emission is often connected to radio emission in L4-T8 dwarfs and is thought to come from aurorae.[54] 2MASS 1237+6526 (T6.5) is an unusual strong H-alpha emitting T-dwarf that was discovered in 2000.[55] It was theorized that the H-alpha emission, UV emission and radio emission come either from a cold companion (1-2.8 R🜨; <500 K) or from an aurora.[56]

Binaries

[edit]

Late T dwarf binaries are less common than L-type binaries. Only 8±6% systems with a T5–Y0 primary are binaries and these systems usually have a separation of a few astronomical units (AU).[57] One well-known T dwarf binary is Epsilon Indi B.[58] This binary consists of a T1 and a T6 dwarf that orbit each other with a separation of 2.65 AU.[59] T dwarf triple systems also exist, with 2M0838+15 being the first fully resolved triple T dwarf that was discovered.[60]

See also

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References

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  1. ^ a b c Kirkpatrick, J. Davy; Reid, I. Neill; Liebert, James; Cutri, Roc M.; Nelson, Brant; Beichman, Charles A.; Dahn, Conard C.; Monet, David G.; Gizis, John E.; Skrutskie, Michael F. (1999-07-01). "Dwarfs Cooler than M: The Definition of Spectral Type L Using Discoveries from the 2 Micron All-Sky Survey (2MASS)". The Astrophysical Journal. 519 (2): 802–833. Bibcode:1999ApJ...519..802K. doi:10.1086/307414. ISSN 0004-637X.
  2. ^ a b Brandt, Timothy D.; Dupuy, Trent J.; Bowler, Brendan P.; Bardalez Gagliuffi, Daniella C.; Faherty, Jacqueline; Brandt, G. Mirek; Michalik, Daniel (October 2020). "A Dynamical Mass of 70 ± 5 MJup for Gliese 229B, the First T Dwarf". The Astronomical Journal. 160 (4): 196. arXiv:1910.01652. Bibcode:2020AJ....160..196B. doi:10.3847/1538-3881/abb45e. ISSN 0004-6256.
  3. ^ a b Gagné, Jonathan; Faherty, Jacqueline K.; Burgasser, Adam J.; Artigau, Étienne; Bouchard, Sandie; Albert, Loïc; Lafrenière, David; Doyon, René; Bardalez Gagliuffi, Daniella C. (2017-05-01). "SIMP J013656.5+093347 Is Likely a Planetary-mass Object in the Carina-Near Moving Group". The Astrophysical Journal. 841 (1): L1. arXiv:1705.01625. Bibcode:2017ApJ...841L...1G. doi:10.3847/2041-8213/aa70e2. ISSN 0004-637X.
  4. ^ a b Macintosh, B.; Graham, J. R.; Barman, T.; De Rosa, R. J.; Konopacky, Q.; Marley, M. S.; Marois, C.; Nielsen, E. L.; Pueyo, L.; Rajan, A.; Rameau, J.; Saumon, D.; Wang, J. J.; Patience, J.; Ammons, M. (2015-10-01). "Discovery and spectroscopy of the young jovian planet 51 Eri b with the Gemini Planet Imager". Science. 350 (6256): 64–67. arXiv:1508.03084. Bibcode:2015Sci...350...64M. doi:10.1126/science.aac5891. ISSN 0036-8075. PMID 26272904.
  5. ^ a b Cushing, Michael C.; Kirkpatrick, J. Davy; Gelino, Christopher R.; Griffith, Roger L.; Skrutskie, Michael F.; Mainzer, A.; Marsh, Kenneth A.; Beichman, Charles A.; Burgasser, Adam J.; Prato, Lisa A.; Simcoe, Robert A.; Marley, Mark S.; Saumon, D.; Freedman, Richard S.; Eisenhardt, Peter R. (2011-12-01). "The Discovery of Y Dwarfs using Data from the Wide-field Infrared Survey Explorer (WISE)". The Astrophysical Journal. 743 (1): 50. arXiv:1108.4678. Bibcode:2011ApJ...743...50C. doi:10.1088/0004-637X/743/1/50. ISSN 0004-637X.
  6. ^ Nakajima, T.; Oppenheimer, B. R.; Kulkarni, S. R.; Golimowski, D. A.; Matthews, K.; Durrance, S. T. (1995-11-01). "Discovery of a cool brown dwarf". Nature. 378 (6556): 463–465. Bibcode:1995Natur.378..463N. doi:10.1038/378463a0. ISSN 0028-0836.
  7. ^ Oppenheimer, B. R.; Kulkarni, S. R.; Matthews, K.; Nakajima, T. (1995-12-01). "Infrared Spectrum of the Cool Brown Dwarf Gl 229B". Science. 270 (5241): 1478–1479. Bibcode:1995Sci...270.1478O. doi:10.1126/science.270.5241.1478. ISSN 0036-8075. PMID 7491492.
  8. ^ Geballe, T. R.; Kulkarni, S. R.; Woodward, Charles E.; Sloan, G. C. (1996-08-01). "The Near-Infrared Spectrum of the Brown Dwarf Gliese 229B". The Astrophysical Journal. 467 (2): L101–L104. arXiv:astro-ph/9606056. Bibcode:1996ApJ...467L.101G. doi:10.1086/310203. ISSN 0004-637X.
  9. ^ Oppenheimer, B. R.; Kulkarni, S. R.; Matthews, K.; van Kerkwijk, M. H. (1998-08-01). "The Spectrum of the Brown Dwarf Gliese 229B". The Astrophysical Journal. 502 (2): 932–943. arXiv:astro-ph/9802299. Bibcode:1998ApJ...502..932O. doi:10.1086/305928. ISSN 0004-637X.
  10. ^ Schultz, A. B.; Allard, F.; Clampin, M.; McGrath, M.; Bruhweiler, F. C.; Valenti, J. A.; Plait, P.; Hulbert, S.; Baum, S.; Woodgate, B. E.; Bowers, C. W.; Kimble, R. A.; Maran, S. P.; Moos, H. W.; Roesler, F. (1998-01-01). "First Results from the Space Telescope Imaging Spectrograph: Optical Spectra of Gliese 229B". The Astrophysical Journal. 492 (2): L181–L184. Bibcode:1998ApJ...492L.181S. doi:10.1086/311103. ISSN 0004-637X.
  11. ^ Saumon, D.; Geballe, T. R.; Leggett, S. K.; Marley, M. S.; Freedman, R. S.; Lodders, K.; Fegley, B., Jr.; Sengupta, S. K. (2000-09-01). "Molecular Abundances in the Atmosphere of the T Dwarf GL 229B". The Astrophysical Journal. 541 (1): 374–389. arXiv:astro-ph/0003353. Bibcode:2000ApJ...541..374S. doi:10.1086/309410. ISSN 0004-637X.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  12. ^ Calamari, Emily; Faherty, Jacqueline K.; Burningham, Ben; Gonzales, Eileen; Bardalez-Gagliuffi, Daniella; Vos, Johanna M.; Gemma, Marina; Whiteford, Niall; Gaarn, Josefine (2022-12-01). "An Atmospheric Retrieval of the Brown Dwarf Gliese 229B". The Astrophysical Journal. 940 (2): 164. arXiv:2210.13614. Bibcode:2022ApJ...940..164C. doi:10.3847/1538-4357/ac9cc9. ISSN 0004-637X.
  13. ^ Howe, Alex R.; McElwain, Michael W.; Mandell, Avi M. (2022-08-01). "GJ 229B: Solving the Puzzle of the First Known T Dwarf with the APOLLO Retrieval Code". The Astrophysical Journal. 935 (2): 107. arXiv:2203.11706. Bibcode:2022ApJ...935..107H. doi:10.3847/1538-4357/ac5590. ISSN 0004-637X.
  14. ^ Howe, Alex R.; Mandell, Avi M.; McElwain, Michael W. (2023-07-01). "Investigating Possible Binarity for GJ 229B". The Astrophysical Journal. 951 (2): L25. arXiv:2306.08450. Bibcode:2023ApJ...951L..25H. doi:10.3847/2041-8213/acdd76. ISSN 0004-637X.
  15. ^ Xuan, Jerry W.; Mérand, A.; Thompson, W.; Zhang, Y.; Lacour, S.; Blakely, D.; Mawet, D.; Oppenheimer, R.; Kammerer, J.; Batygin, K.; Sanghi, A.; Wang, J.; Ruffio, J.-B.; Liu, M. C.; Knutson, H. (2024-10-16). "The cool brown dwarf Gliese 229 B is a close binary". Nature: 1–5. arXiv:2410.11953. doi:10.1038/s41586-024-08064-x. ISSN 1476-4687.
  16. ^ Burgasser, Adam J.; Kirkpatrick, J. Davy; Cutri, Roc M.; McCallon, Howard; Kopan, Gene; Gizis, John E.; Liebert, James; Reid, I. Neill; Brown, Michael E.; Monet, David G.; Dahn, Conard C.; Beichman, Charles A.; Skrutskie, Michael F. (2000-03-01). "Discovery of a Brown Dwarf Companion to Gliese 570ABC: A 2MASS T Dwarf Significantly Cooler than Gliese 229B". The Astrophysical Journal. 531 (1): L57–L60. arXiv:astro-ph/0001194. Bibcode:2000ApJ...531L..57B. doi:10.1086/312522. ISSN 0004-637X. PMID 10673414.
  17. ^ Strauss, Michael A.; Fan, Xiaohui; Gunn, James E.; Leggett, S. K.; Geballe, T. R.; Pier, Jeffrey R.; Lupton, Robert H.; Knapp, G. R.; Annis, James; Brinkmann, J.; Crocker, J. H.; Csabai, István; Fukugita, Masataka; Golimowski, David A.; Harris, Frederick H. (1999-09-01). "The Discovery of a Field Methane Dwarf from Sloan Digital Sky Survey Commissioning Data". The Astrophysical Journal. 522 (1): L61–L64. arXiv:astro-ph/9905391. Bibcode:1999ApJ...522L..61S. doi:10.1086/312218. ISSN 0004-637X.
  18. ^ Tsvetanov, Zlatan I.; Golimowski, David A.; Zheng, Wei; Geballe, T. R.; Leggett, S. K.; Ford, Holland C.; Davidsen, Arthur F.; Uomoto, Alan; Fan, Xiaohui; Knapp, G. R.; Strauss, Michael A.; Brinkmann, J.; Lamb, D. Q.; Newberg, Heidi Jo; Rechenmacher, Ron (2000-03-01). "The Discovery of a Second Field Methane Brown Dwarf from Sloan Digital Sky Survey Commissioning Data". The Astrophysical Journal. 531 (1): L61–L65. arXiv:astro-ph/0001062. Bibcode:2000ApJ...531L..61T. doi:10.1086/312515. ISSN 0004-637X. PMID 10673415.
  19. ^ Leggett, S. K.; Geballe, T. R.; Fan, Xiaohui; Schneider, Donald P.; Gunn, James E.; Lupton, Robert H.; Knapp, G. R.; Strauss, Michael A.; McDaniel, Alex; Golimowski, David A.; Henry, Todd J.; Peng, Eric; Tsvetanov, Zlatan I.; Uomoto, Alan; Zheng, Wei (2000-06-01). "The Missing Link: Early Methane (T) Dwarfs in the Sloan Digital Sky Survey". The Astrophysical Journal. 536 (1): L35–L38. arXiv:astro-ph/0004408. Bibcode:2000ApJ...536L..35L. doi:10.1086/312728. ISSN 0004-637X. PMID 10849414.
  20. ^ Geballe, T. R.; Knapp, G. R.; Leggett, S. K.; Fan, X.; Golimowski, D. A.; Anderson, S.; Brinkmann, J.; Csabai, I.; Gunn, J. E.; Hawley, S. L.; Hennessy, G.; Henry, T. J.; Hill, G. J.; Hindsley, R. B.; Ivezić, Ž. (2002-01-01). "Toward Spectral Classification of L and T Dwarfs: Infrared and Optical Spectroscopy and Analysis". The Astrophysical Journal. 564 (1): 466–481. arXiv:astro-ph/0108443. Bibcode:2002ApJ...564..466G. doi:10.1086/324078. ISSN 0004-637X.
  21. ^ Lucas, P. W.; Tinney, C. G.; Burningham, Ben; Leggett, S. K.; Pinfield, David J.; Smart, Richard; Jones, Hugh R. A.; Marocco, Federico; Barber, Robert J.; Yurchenko, Sergei N.; Tennyson, Jonathan; Ishii, Miki; Tamura, Motohide; Day-Jones, Avril C.; Adamson, Andrew (2010-10-01). "The discovery of a very cool, very nearby brown dwarf in the Galactic plane". Monthly Notices of the Royal Astronomical Society. 408 (1): L56–L60. arXiv:1004.0317. Bibcode:2010MNRAS.408L..56L. doi:10.1111/j.1745-3933.2010.00927.x. ISSN 0035-8711.
  22. ^ Bochanski, John J.; Burgasser, Adam J.; Simcoe, Robert A.; West, Andrew A. (2011-11-01). "FIRE Spectroscopy of the Ultra-cool Brown Dwarf, UGPS J072227.51-054031.2: Kinematics, Rotation and Atmospheric Parameters". The Astronomical Journal. 142 (5): 169. arXiv:1109.2897. Bibcode:2011AJ....142..169B. doi:10.1088/0004-6256/142/5/169. ISSN 0004-6256.
  23. ^ Kirkpatrick, J. Davy; Cushing, Michael C.; Gelino, Christopher R.; Griffith, Roger L.; Skrutskie, Michael F.; Marsh, Kenneth A.; Wright, Edward L.; Mainzer, A.; Eisenhardt, Peter R.; McLean, Ian S.; Thompson, Maggie A.; Bauer, James M.; Benford, Dominic J.; Bridge, Carrie R.; Lake, Sean E. (2011-12-01). "The First Hundred Brown Dwarfs Discovered by the Wide-field Infrared Survey Explorer (WISE)". The Astrophysical Journal Supplement Series. 197 (2): 19. arXiv:1108.4677. Bibcode:2011ApJS..197...19K. doi:10.1088/0067-0049/197/2/19. ISSN 0067-0049.
  24. ^ Burgasser, Adam J.; Sheppard, Scott S.; Luhman, K. L. (2013-08-01). "Resolved Near-infrared Spectroscopy of WISE J104915.57-531906.1AB: A Flux-reversal Binary at the L dwarf/T Dwarf Transition". The Astrophysical Journal. 772 (2): 129. arXiv:1303.7283. Bibcode:2013ApJ...772..129B. doi:10.1088/0004-637X/772/2/129. ISSN 0004-637X.
  25. ^ a b Burgasser, Adam J.; Marley, Mark S.; Ackerman, Andrew S.; Saumon, Didier; Lodders, Katharina; Dahn, Conard C.; Harris, Hugh C.; Kirkpatrick, J. Davy (2002-06-01). "Evidence of Cloud Disruption in the L/T Dwarf Transition". The Astrophysical Journal. 571 (2): L151–L154. arXiv:astro-ph/0205051. Bibcode:2002ApJ...571L.151B. doi:10.1086/341343. ISSN 0004-637X.
  26. ^ Beiler, Samuel A.; Cushing, Michael C.; Kirkpatrick, J. Davy; Schneider, Adam C.; Mukherjee, Sagnick; Marley, Mark S.; Marocco, Federico; Smart, Richard L. (11 Jul 2024). "Precise Bolometric Luminosities and Effective Temperatures of 23 late-T and Y dwarfs Obtained with JWST". The Astrophysical Journal. 973 (2): 107. arXiv:2407.08518. Bibcode:2024ApJ...973..107B. doi:10.3847/1538-4357/ad6301.
  27. ^ Tannock, Megan E.; Metchev, Stanimir; Hood, Callie E.; Mace, Gregory N.; Fortney, Jonathan J.; Morley, Caroline V.; Jaffe, Daniel T.; Lupu, Roxana (2022-08-01). "A 1.46-2.48 μm spectroscopic atlas of a T6 dwarf (1060 K) atmosphere with IGRINS: first detections of H2S and H2, and verification of H2O, CH4, and NH3 line lists". Monthly Notices of the Royal Astronomical Society. 514 (3): 3160–3178. arXiv:2206.03519. Bibcode:2022MNRAS.514.3160T. doi:10.1093/mnras/stac1412. ISSN 0035-8711.
  28. ^ Burgasser, Adam J.; Kirkpatrick, J. Davy; Brown, Michael E.; Reid, I. Neill; Burrows, Adam; Liebert, James; Matthews, Keith; Gizis, John E.; Dahn, Conard C.; Monet, David G.; Cutri, Roc M.; Skrutskie, Michael F. (2002-01-01). "The Spectra of T Dwarfs. I. Near-Infrared Data and Spectral Classification". The Astrophysical Journal. 564 (1): 421–451. arXiv:astro-ph/0108452. Bibcode:2002ApJ...564..421B. doi:10.1086/324033. ISSN 0004-637X.
  29. ^ Burgasser, Adam J.; Burrows, Adam; Kirkpatrick, J. Davy (2006). "Method for determining the physical properties of the coldest known brown dwarfs". The Astrophysical Journal. 639 (2): 1095–1113. arXiv:astro-ph/0510707. Bibcode:2006ApJ...639.1095B. doi:10.1086/499344. ISSN 0004-637X. S2CID 9291848.
  30. ^ Schneider, Adam C.; Burgasser, Adam J.; Gerasimov, Roman; Marocco, Federico; Gagne, Jonathan; Goodman, Sam; et al. (24 July 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. ISSN 1538-4357. S2CID 220403370.
  31. ^ Lodieu, N.; Zapatero Osorio, M. R.; Martín, E. L.; Rebolo López, R.; Gauza, B. (1 July 2022). "Physical properties and trigonometric distance of the peculiar dwarf WISE J181005.5−101002.3". Astronomy and Astrophysics. 663: A84. arXiv:2206.13097. Bibcode:2022A&A...663A..84L. doi:10.1051/0004-6361/202243516. ISSN 0004-6361. S2CID 249836684.
  32. ^ 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)
  33. ^ Burgasser, Adam J.; Bezanson, Rachel; Labbe, Ivo; Brammer, Gabriel; Cutler, Sam E.; Furtak, Lukas J.; Greene, Jenny E.; Gerasimov, Roman; Leja, Joel; Pan, Richard; Price, Sedona H.; Wang, Bingjie; Weaver, John R.; Whitaker, Katherine E.; Fujimoto, Seiji (2024-02-01). "UNCOVER: JWST Spectroscopy of Three Cold Brown Dwarfs at Kiloparsec-scale Distances". The Astrophysical Journal. 962 (2): 177. arXiv:2308.12107. Bibcode:2024ApJ...962..177B. doi:10.3847/1538-4357/ad206f. ISSN 0004-637X.
  34. ^ Chabrier, Gilles; Baraffe, Isabelle; Phillips, Mark; Debras, Florian (2023-03-01). "Impact of a new H/He equation of state on the evolution of massive brown dwarfs. New determination of the hydrogen burning limit". Astronomy and Astrophysics. 671: A119. arXiv:2212.07153. Bibcode:2023A&A...671A.119C. doi:10.1051/0004-6361/202243832. ISSN 0004-6361.
  35. ^ Best, William M. J. (February 4, 2024). "The UltracoolSheet: Photometry, Astrometry, Spectroscopy, and Multiplicity for 4000+ Ultracool Dwarfs and Imaged Exoplanets". zenodo. doi:10.5281/zenodo.10573247. Retrieved 2024-09-29.
  36. ^ Sanghi, Aniket; Liu, Michael C.; Best, William M. J.; Dupuy, Trent J.; Siverd, Robert J.; Zhang, Zhoujian; Hurt, Spencer A.; Magnier, Eugene A.; Aller, Kimberly M.; Deacon, Niall R. (2023-12-01). "The Hawaii Infrared Parallax Program. VI. The Fundamental Properties of 1000+ Ultracool Dwarfs and Planetary-mass Objects Using Optical to Mid-infrared Spectral Energy Distributions and Comparison to BT-Settl and ATMO 2020 Model Atmospheres". The Astrophysical Journal. 959 (1): 63. arXiv:2309.03082. Bibcode:2023ApJ...959...63S. doi:10.3847/1538-4357/acff66. ISSN 0004-637X.
  37. ^ Aniket, Sanghi (November 8, 2023). "Table of Ultracool Fundamental Properties". zenodo. doi:10.5281/zenodo.10086810. Retrieved 2024-09-28.
  38. ^ Day-Jones, A. C.; Pinfield, D. J.; Ruiz, M. T.; Beaumont, H.; Burningham, B.; Gallardo, J.; Gianninas, A.; Bergeron, P.; Napiwotzki, R.; Jenkins, J. S.; Zhang, Z. H.; Murray, D. N.; Catalán, S.; Gomes, J. (2011-01-01). "Discovery of a T dwarf + white dwarf binary system". Monthly Notices of the Royal Astronomical Society. 410 (2): 705–716. arXiv:1008.2960. Bibcode:2011MNRAS.410..705D. doi:10.1111/j.1365-2966.2010.17469.x. ISSN 0035-8711.
  39. ^ Marocco, Federico; Kirkpatrick, J. Davy; Schneider, Adam C.; Meisner, Aaron M.; Popinchalk, Mark; Gelino, Christopher R.; Faherty, Jacqueline K.; Burgasser, Adam J.; Caselden, Dan; Gagné, Jonathan; Aganze, Christian; Bardalez Gagliuffi, Daniella C.; Casewell, Sarah L.; Hsu, Chih-Chun; Kiman, Rocio (2024-06-01). "Thirteen New M Dwarf + T Dwarf Pairs Identified with WISE/NEOWISE". The Astrophysical Journal. 967 (2): 147. arXiv:2404.14324. Bibcode:2024ApJ...967..147M. doi:10.3847/1538-4357/ad3f1d. ISSN 0004-637X.
  40. ^ Rothermich, Austin; Faherty, Jacqueline K.; Bardalez-Gagliuffi, Daniella; Schneider, Adam C.; Kirkpatrick, J. Davy; Meisner, Aaron M.; Burgasser, Adam J.; Kuchner, Marc; Allers, Katelyn; Gagné, Jonathan; Caselden, Dan; Calamari, Emily; Popinchalk, Mark; Suárez, Genaro; Gerasimov, Roman (2024-06-01). "89 New Ultracool Dwarf Comoving Companions Identified with the Backyard Worlds: Planet 9 Citizen Science Project". The Astronomical Journal. 167 (6): 253. arXiv:2403.04592. Bibcode:2024AJ....167..253R. doi:10.3847/1538-3881/ad324e. ISSN 0004-6256.
  41. ^ Mace, Gregory N.; Mann, Andrew W.; Skiff, Brian A.; Sneden, Christopher; Kirkpatrick, J. Davy; Schneider, Adam C.; Kidder, Benjamin; Gosnell, Natalie M.; Kim, Hwihyun; Mulligan, Brian W.; Prato, L.; Jaffe, Daniel (2018-02-01). "Wolf 1130: A Nearby Triple System Containing a Cool, Ultramassive White Dwarf". The Astrophysical Journal. 854 (2): 145. arXiv:1802.04803. Bibcode:2018ApJ...854..145M. doi:10.3847/1538-4357/aaa8dd. ISSN 0004-637X.
  42. ^ Gagné, Jonathan; Burgasser, Adam J.; Faherty, Jacqueline K.; Lafreniére, David; Doyon, René; Filippazzo, Joseph C.; Bowsher, Emily; Nicholls, Christine P. (2015-07-01). "SDSS J111010.01+011613.1: A New Planetary-mass T Dwarf Member of the AB Doradus Moving Group". The Astrophysical Journal. 808 (1): L20. arXiv:1506.04195. Bibcode:2015ApJ...808L..20G. doi:10.1088/2041-8205/808/1/L20. ISSN 0004-637X.
  43. ^ Artigau, Étienne; Bouchard, Sandie; Doyon, René; Lafrenière, David (2009-08-01). "Photometric Variability of the T2.5 Brown Dwarf SIMP J013656.5+093347: Evidence for Evolving Weather Patterns". The Astrophysical Journal. 701 (2): 1534–1539. arXiv:0906.3514. Bibcode:2009ApJ...701.1534A. doi:10.1088/0004-637X/701/2/1534. ISSN 0004-637X.
  44. ^ a b Kao, Melodie M.; Hallinan, Gregg; Pineda, J. Sebastian; Stevenson, David; Burgasser, Adam (2018-08-01). "The Strongest Magnetic Fields on the Coolest Brown Dwarfs". The Astrophysical Journal Supplement Series. 237 (2): 25. arXiv:1808.02485. Bibcode:2018ApJS..237...25K. doi:10.3847/1538-4365/aac2d5. ISSN 0067-0049.
  45. ^ Zhang, Zhoujian; Liu, Michael C.; Best, William M. J.; Dupuy, Trent J.; Siverd, Robert J. (2021-04-01). "The Hawaii Infrared Parallax Program. V. New T-dwarf Members and Candidate Members of Nearby Young Moving Groups". The Astrophysical Journal. 911 (1): 7. arXiv:2102.05045. Bibcode:2021ApJ...911....7Z. doi:10.3847/1538-4357/abe3fa. ISSN 0004-637X.
  46. ^ Heinze, A. N.; Metchev, Stanimir; Kurtev, Radostin; Gillon, Michael (2021-10-01). "Weather on Other Worlds. VI. Optical Spectrophotometry of Luhman 16B Reveals Large-amplitude Variations in the Alkali Lines". The Astrophysical Journal. 920 (2): 108. arXiv:2107.10995. Bibcode:2021ApJ...920..108H. doi:10.3847/1538-4357/ac178b. ISSN 0004-637X.
  47. ^ Vos, Johanna M.; Burningham, Ben; Faherty, Jacqueline K.; Alejandro, Sherelyn; Gonzales, Eileen; Calamari, Emily; Bardalez Gagliuffi, Daniella; Visscher, Channon; Tan, Xianyu; Morley, Caroline V.; Marley, Mark; Gemma, Marina E.; Whiteford, Niall; Gaarn, Josefine; Park, Grace (2023-02-01). "Patchy Forsterite Clouds in the Atmospheres of Two Highly Variable Exoplanet Analogs". The Astrophysical Journal. 944 (2): 138. arXiv:2212.07399. Bibcode:2023ApJ...944..138V. doi:10.3847/1538-4357/acab58. ISSN 0004-637X.
  48. ^ Vos, Johanna M.; Faherty, Jacqueline K.; Gagné, Jonathan; Marley, Mark; Metchev, Stanimir; Gizis, John; Rice, Emily L.; Cruz, Kelle (2022-01-01). "Let the Great World Spin: Revealing the Stormy, Turbulent Nature of Young Giant Exoplanet Analogs with the Spitzer Space Telescope". The Astrophysical Journal. 924 (2): 68. arXiv:2201.04711. Bibcode:2022ApJ...924...68V. doi:10.3847/1538-4357/ac4502. ISSN 0004-637X.
  49. ^ a b Morley, Caroline V.; Fortney, Jonathan J.; Marley, Mark S.; Visscher, Channon; Saumon, Didier; Leggett, S. K. (2012-09-01). "Neglected Clouds in T and Y Dwarf Atmospheres". The Astrophysical Journal. 756 (2): 172. arXiv:1206.4313. Bibcode:2012ApJ...756..172M. doi:10.1088/0004-637X/756/2/172. ISSN 0004-637X. S2CID 118398946.
  50. ^ Rajan, A.; Patience, J.; Wilson, P. A.; Bulger, J.; De Rosa, R. J.; Ward-Duong, K.; Morley, C.; Pont, F.; Windhorst, R. (2015-04-01). "The brown dwarf atmosphere monitoring (BAM) project - II. Multi-epoch monitoring of extremely cool brown dwarfs". Monthly Notices of the Royal Astronomical Society. 448 (4): 3775–3783. arXiv:1502.01346. Bibcode:2015MNRAS.448.3775R. doi:10.1093/mnras/stv181. ISSN 0035-8711.
  51. ^ Route, M.; Wolszczan, A. (2012-03-01). "The Arecibo Detection of the Coolest Radio-flaring Brown Dwarf". The Astrophysical Journal. 747 (2): L22. arXiv:1202.1287. Bibcode:2012ApJ...747L..22R. doi:10.1088/2041-8205/747/2/L22. ISSN 0004-637X.
  52. ^ Vedantham, H. K.; Callingham, J. R.; Shimwell, T. W.; Dupuy, T.; Best, William M. J.; Liu, Michael C.; Zhang, Zhoujian; De, K.; Lamy, L.; Zarka, P.; Röttgering, H. J. A.; Shulevski, A. (2020-11-01). "Direct Radio Discovery of a Cold Brown Dwarf". The Astrophysical Journal. 903 (2): L33. arXiv:2010.01915. Bibcode:2020ApJ...903L..33V. doi:10.3847/2041-8213/abc256. ISSN 0004-637X.
  53. ^ Rose, Kovi; Pritchard, Joshua; Murphy, Tara; Caleb, Manisha; Dobie, Dougal; Driessen, Laura; Duchesne, Stefan W.; Kaplan, David L.; Lenc, Emil; Wang, Ziteng (2023-07-01). "Periodic Radio Emission from the T8 Dwarf WISE J062309.94-045624.6". The Astrophysical Journal. 951 (2): L43. arXiv:2306.15219. Bibcode:2023ApJ...951L..43R. doi:10.3847/2041-8213/ace188. ISSN 0004-637X.
  54. ^ Pineda, J. Sebastian; Hallinan, Gregg; Kao, Melodie M. (2017-09-01). "A Panchromatic View of Brown Dwarf Aurorae". The Astrophysical Journal. 846 (1): 75. arXiv:1708.02942. Bibcode:2017ApJ...846...75P. doi:10.3847/1538-4357/aa8596. ISSN 0004-637X.
  55. ^ Burgasser, Adam J.; Kirkpatrick, J. Davy; Reid, I. Neill; Liebert, James; Gizis, John E.; Brown, Michael E. (2000-07-01). "Detection of Hα Emission in a Methane (T Type) Brown Dwarf". The Astronomical Journal. 120 (1): 473–478. arXiv:astro-ph/0003291. Bibcode:2000AJ....120..473B. doi:10.1086/301423. ISSN 0004-6256.
  56. ^ Saur, Joachim; Willmes, Clarissa; Fischer, Christian; Wennmacher, Alexandre; Roth, Lorenz; Youngblood, Allison; Strobel, Darrell F.; Reiners, Ansgar (2021-11-01). "Brown dwarfs as ideal candidates for detecting UV aurora outside the Solar System: Hubble Space Telescope observations of 2MASS J1237+6526". Astronomy and Astrophysics. 655: A75. arXiv:2109.00827. Bibcode:2021A&A...655A..75S. doi:10.1051/0004-6361/202040230. ISSN 0004-6361.
  57. ^ Fontanive, Clémence; Biller, Beth; Bonavita, Mariangela; Allers, Katelyn (2018-09-01). "Constraining the multiplicity statistics of the coolest brown dwarfs: binary fraction continues to decrease with spectral type". Monthly Notices of the Royal Astronomical Society. 479 (2): 2702–2727. arXiv:1806.08737. Bibcode:2018MNRAS.479.2702F. doi:10.1093/mnras/sty1682. ISSN 0035-8711.
  58. ^ Scholz, R.-D.; McCaughrean, M. J.; Lodieu, N.; Kuhlbrodt, B. (February 2003). "ε Indi B: A new benchmark T dwarf". Astronomy and Astrophysics. 398 (3): L29–L33. arXiv:astro-ph/0212487. Bibcode:2003A&A...398L..29S. doi:10.1051/0004-6361:20021847. S2CID 119474823.
  59. ^ McCaughrean, M. J.; Close, L. M.; Scholz, R. -D.; Lenzen, R.; Biller, B.; Brandner, W.; Hartung, M.; Lodieu, N. (2004-01-01). "ɛ Indi Ba,Bb: The nearest binary brown dwarf". Astronomy and Astrophysics. 413: 1029–1036. arXiv:astro-ph/0309256. Bibcode:2004A&A...413.1029M. doi:10.1051/0004-6361:20034292. ISSN 0004-6361.
  60. ^ Radigan, Jacqueline; Jayawardhana, Ray; Lafrenière, David; Dupuy, Trent J.; Liu, Michael C.; Scholz, Alexander (2013-11-01). "Discovery of a Visual T-dwarf Triple System and Binarity at the L/T Transition". The Astrophysical Journal. 778: 36. arXiv:1308.5702. Bibcode:2013ApJ...778...36R. doi:10.1088/0004-637X/778/1/36. ISSN 0004-637X.
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