Spectral Properties of Brown Dwarfs and Unbound Planetary Mass Objects

  • Jacqueline K. FahertyEmail author
Reference work entry


Brown dwarfs overlap in effective temperature, luminosity, and mass with both the lowest mass stars and the highest mass planets. Specifically, young brown dwarfs and directly imaged exoplanets have enticingly similar photometric and spectroscopic characteristics, indicating that their cool, low gravity atmospheres should be studied in concert. Similarities between the peculiar-shaped H band, near and mid-IR photometry, and location on color magnitude diagrams provide important clues about how to extract physical properties of planets from current brown dwarf observations. In this chapter, objects newly assigned to 10–150 Myr nearby moving groups – many of which are unbound planetary mass objects – will be discussed, the diversity of this uniform age-calibrated brown dwarf sample will be highlighted, and the implication for understanding current and future planetary data will be reflected upon.


  1. Ackerman AS, Marley MS (2001) Precipitating condensation clouds in substellar atmospheres. ApJ 556:872ADSCrossRefGoogle Scholar
  2. Allard F, Hauschildt PH (1995) Model atmospheres for M (sub)dwarf stars. 1: the base model grid. ApJ 445:433ADSCrossRefGoogle Scholar
  3. Allers KN, Liu MC (2013) A near-infrared spectroscopic study of young field ultracool dwarfs. ApJ 772:79ADSCrossRefGoogle Scholar
  4. Allard F, Hauschildt PH, Alexander DR, Tamanai A, Schweitzer A (2001) The limiting effects of dust in brown dwarf model atmospheres. ApJ 556:357ADSCrossRefGoogle Scholar
  5. Barman TS, Macintosh B, Konopacky QM, Marois C (2011) Clouds and chemistry in the atmosphere of extrasolar planet HR8799b. ApJ 733:65ADSCrossRefGoogle Scholar
  6. Biller BA, Vos J, Bonavita M et al (2015) Variability in a young, L/T transition planetary-mass object. ApJ 813:L23ADSCrossRefGoogle Scholar
  7. Bowler BP, Liu MC, Kraus AL, Mann AW (2014) Spectroscopic confirmation of young planetary-mass companions on wide orbits. ApJ 784:65ADSCrossRefGoogle Scholar
  8. Burgasser AJ, Liu MC, Ireland MJ, Cruz KL, Dupuy TJ (2008) Subtle signatures of multiplicity in late-type dwarf spectra: the unresolved M8.5 + T5 binary 2MASS J03202839-0446358. ApJ 681:579ADSCrossRefGoogle Scholar
  9. Burrows A, Hubbard WB, Lunine JI et al (1997) Extra-solar giant planet and brown dwarf models. ASP Conf Ser 119:9ADSGoogle Scholar
  10. Chauvin G, Lagrange A-M, Dumas C et al (2004) A giant planet candidate near a young brown dwarf. Direct VLT/NACO observations using IR wavefront sensing. A&A 425:L29ADSCrossRefGoogle Scholar
  11. Cruz KL, Reid IN, Kirkpatrick JD, et al (2007) Meeting the cool neighbors. IX. The luminosity function of M7-L8 ultracool dwarfs in the field. AJ 133:439ADSCrossRefGoogle Scholar
  12. Cruz KL, Kirkpatrick JD, Burgasser AJ (2009) Young L dwarfs identified in the field: a preliminary low-gravity, optical spectral sequence from L0 to L5. AJ 137:3345ADSCrossRefGoogle Scholar
  13. Cruz KL, Núñez A, Burgasser AJ et al (2018) Meeting the cool neighbors. XII. An optically anchored analysis of the near-infrared spectra of L dwarfs. AJ 155:34ADSCrossRefGoogle Scholar
  14. Currie T, Burrows A, Itoh Y et al (2011) A combined subaru/VLT/MMT 15m study of planets orbiting HR 8799: implications for atmospheric properties, masses, and formation. ApJ 729:128ADSCrossRefGoogle Scholar
  15. Currie T, Daemgen S, Debes J et al (2014) Direct imaging and spectroscopy of a candidate companion below/near the deuterium-burning limit in the young binary star system, ROXs 42B. ApJ 780:L30ADSCrossRefGoogle Scholar
  16. Cushing MC, Marley MS, Saumon D et al (2008) Atmospheric parameters of field L and T dwarfs. ApJ 678:1372ADSCrossRefGoogle Scholar
  17. Faherty JK, Burgasser AJ, Cruz KL et al (2009) The brown dwarf kinematics project I. Proper motions and tangential velocities for a large sample of late-type M, L, and T dwarfs. AJ 137:1ADSCrossRefGoogle Scholar
  18. Faherty JK, Burgasser AJ, Walter FM et al (2012) The brown dwarf kinematics project (BDKP). III. Parallaxes for 70 ultracool dwarfs. ApJ 752:56ADSCrossRefGoogle Scholar
  19. Faherty JK, Rice EL, Cruz KL, Mamajek EE, Núñez A (2013) 2MASS J035523.37+113343.7: a young, dusty, nearby, isolated brown dwarf resembling a giant exoplanet. AJ 145:2ADSCrossRefGoogle Scholar
  20. Faherty JK, Riedel AR, Cruz KL et al (2016) Population properties of brown dwarf analogs to exoplanets. ApJS 225:10ADSCrossRefGoogle Scholar
  21. Filippazzo JC, Rice EL, Faherty J et al (2015) Fundamental parameters and spectral energy distributions of young and field age objects with masses spanning the stellar to planetary regime. ApJ 810:158ADSCrossRefGoogle Scholar
  22. Gagné J, Faherty JK, Cruz K, et al (2014) The coolest isolated brown dwarf candidate member of TWA. ApJ 785:L14ADSCrossRefGoogle Scholar
  23. Gagné, J., Burgasser AJ, Faherty JK et al (2015a) SDSS J111010.01+011613.1: a new planetary-mass T dwarf member of the AB Doradus moving group. ApJ 808:L20ADSCrossRefGoogle Scholar
  24. Gagné J, Faherty JK, Cruz KL et al (2015b) BANYAN. VII. A new population of young substellar candidate members of nearby moving groups from the BASS survey. ApJS 219:33ADSCrossRefGoogle Scholar
  25. Gagné J, Lafrenière D, Doyon R, Malo L, Artigau É (2015c) BANYAN. V. A systematic all-sky survey for new very late-type low-mass stars and brown dwarfs in nearby young moving groups. ApJ 798:73ADSCrossRefGoogle Scholar
  26. Gagné J, Faherty JK, Burgasser AJ et al (2017) SIMP J013656.5+093347 is likely a planetary-mass object in the Carina-near moving group. ApJ 841:L1ADSCrossRefGoogle Scholar
  27. Gagné J, Allers KN, Theissen CA et al (2018) 2MASS J13243553+6358281 is an early T-type planetary-mass object in the AB Doradus moving group. ApJ 854:27. ArXiv e-printsADSCrossRefGoogle Scholar
  28. Gizis JE, Faherty JK, Liu MC et al (2012) Discovery of an unusually red L-type brown dwarf. AJ 144:94ADSCrossRefGoogle Scholar
  29. Gizis JE, Allers KN, Liu MC et al (2015) WISEP J004701.06+680352.1: an intermediate surface gravity, dusty brown dwarf in the AB Dor moving group. ApJ 799:203ADSCrossRefGoogle Scholar
  30. Kellogg K, Metchev S, Gagné J, Faherty J (2016) The nearest isolated member of the TW hydrae association is a giant planet analog. ApJ 821:L15ADSCrossRefGoogle Scholar
  31. Kirkpatrick JD (2005) New spectral types L and T. ARA&A 43:195ADSCrossRefGoogle Scholar
  32. Kirkpatrick JD, Looper DL, Burgasser AJ et al (2010) Discoveries from a near-infrared proper motion survey using multi-epoch two micron all-sky survey data. ApJS 190:100ADSCrossRefGoogle Scholar
  33. Kraus AL, Ireland MJ, Cieza LA, et al (2014) Three wide planetary-mass companions to FW Tau, ROXs 12, and ROXs 42B. ApJ 781:20ADSCrossRefGoogle Scholar
  34. Lafrenière D, Jayawardhana R, van Kerkwijk MH (2008) Direct imaging and spectroscopy of a planetary-mass candidate companion to a young solar analog. ApJ 689:L153ADSCrossRefGoogle Scholar
  35. Lagrange A-M., Bonnefoy M, Chauvin G et al (2010) A giant planet imaged in the disk of the young star β Pictoris. Science 329:57ADSCrossRefGoogle Scholar
  36. Liu MC, Dupuy TJ, Allers KN (2013) Infrared parallaxes of young field brown dwarfs and connections to directly imaged gas-giant exoplanets. Astron Nachr. 334:85ADSCrossRefGoogle Scholar
  37. Liu MC, Dupuy TJ, Allers KN (2016) The Hawaii infrared parallax program. II. Young ultracool field dwarfs. ApJ 833:96ADSCrossRefGoogle Scholar
  38. Lodders K (1999) Alkali element chemistry in cool dwarf atmospheres. ApJ 519:793ADSCrossRefGoogle Scholar
  39. Lodieu N, Zapatero Osorio MR, Béjar VJS, Peña Ramírez K (2018) The optical + infrared L dwarf spectral sequence of young planetary-mass objects in the Upper Scorpius association. MNRAS 473:2020ADSCrossRefGoogle Scholar
  40. Macintosh B, Graham JR, Barman T et al (2015) Discovery and spectroscopy of the young Jovian planet 51 Eri b with the Gemini planet imager. Science 350:64ADSCrossRefGoogle Scholar
  41. Madhusudhan N, Burrows A, Currie T (2011) Model atmospheres for massive gas giants with thick clouds: application to the HR 8799 planets and predictions for future detections. ApJ 737:34ADSCrossRefGoogle Scholar
  42. Males JR, Close LM, Morzinski KM et al (2014) Magellan adaptive optics first-light observations of the exoplanet β Pic B. I. Direct imaging in the far-red optical with MagAO+VisAO and in the Near-IR with NICI. ApJ 786:32ADSCrossRefGoogle Scholar
  43. Marley MS, Saumon D, Cushing M et al (2012) Masses, radii, and cloud properties of the HR 8799 planets. ApJ 754:135. ArXiv e-printsADSCrossRefGoogle Scholar
  44. Marois C, Macintosh B, Barman T et al (2008) Direct imaging of multiple planets orbiting the star HR 8799. Science 322:1348ADSCrossRefGoogle Scholar
  45. Marois C, Zuckerman B, Konopacky QM, Macintosh B, Barman T (2010) Images of a fourth planet orbiting HR 8799. Nature 468:1080ADSCrossRefGoogle Scholar
  46. Metchev SA, Hillenbrand LA (2006) HD 203030B: an unusually cool young substellar companion near the L/T transition. ApJ 651:1166ADSCrossRefGoogle Scholar
  47. Metchev SA, Heinze A, Apai D et al (2015) Weather on other worlds. II. Survey results: spots are ubiquitous on L and T dwarfs. ApJ 799:154ADSCrossRefGoogle Scholar
  48. Mohanty S, Jayawardhana R, Huélamo N, Mamajek E (2007) The planetary mass companion 2MASS 1207-3932B: temperature, mass, and evidence for an edge-on disk. ApJ 657:1064ADSCrossRefGoogle Scholar
  49. Naud M-E, Artigau É, Malo L et al (2014) Discovery of a wide planetary-mass companion to the young M3 star GU Psc. ApJ 787:5ADSCrossRefGoogle Scholar
  50. Rice EL, Barman T, Mclean IS, Prato L, Kirkpatrick JD (2010a) Physical properties of young brown dwarfs and very low mass stars inferred from high-resolution model spectra. ApJS 186:63ADSCrossRefGoogle Scholar
  51. Rice EL, Faherty JK, Cruz KL (2010b) The lowest-mass member of the β Pictoris moving group. ApJ 715:L165ADSCrossRefGoogle Scholar
  52. Schneider AC, Cushing MC, Kirkpatrick JD et al (2014) Discovery of the young L dwarf WISE J174102.78-464225.5. AJ 147:34Google Scholar
  53. Schneider AC, Windsor J, Cushing MC, Kirkpatrick JD, Wright EL (2016) WISEA J114724.10-204021.3: a free-floating planetary mass member of the TW Hya association. ApJ 822:L1ADSCrossRefGoogle Scholar
  54. Thompson MA, Kirkpatrick JD, Mace GN et al (2013) Nearby M, L, and T dwarfs discovered by the wide-field infrared survey explorer (WISE). PASP 125:809ADSCrossRefGoogle Scholar
  55. Tremblin P, Chabrier G, Baraffe I et al (2017) Cloudless atmospheres for young low-gravity substellar objects. ApJ 850:46ADSCrossRefGoogle Scholar
  56. Tsuji T, Ohnaka K, Aoki W, Nakajima T (1996) Evolution of dusty photospheres through red to brown dwarfs: how dust forms in very low mass objects. A&A 308:L29ADSGoogle Scholar
  57. Vos JM, Allers KN, Biller BA (2017) The viewing geometry of brown dwarfs influences their observed colors and variability amplitudes. ApJ 842:78ADSCrossRefGoogle Scholar
  58. Woitke P, Helling C (2004) Dust in brown dwarfs. III. Formation and structure of quasi-static cloud layers. A&A 414:335ADSCrossRefGoogle Scholar
  59. Zapatero Osorio MR, Béjar VJS, Martín EL, et al (2014a) Spectroscopic follow-up of L- and T-type proper-motion member candidates in the Pleiades. A&A 572:A67ADSCrossRefGoogle Scholar
  60. Zapatero Osorio MR, Béjar VJS, Miles-Páez PA et al (2014b) Trigonometric parallaxes of young field L dwarfs. A&A 568:A6ADSCrossRefGoogle Scholar

Copyright information

© Springer International Publishing AG, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Department of AstrophysicsAmerican Museum of Natural HistoryNew YorkUSA

Personalised recommendations