Skip to main content
SpringerLink
Log in

Y Dwarfs: The Challenge of Discovering the Coldest Substellar Population in the Solar Neighborhood

  • Reference work entry
  • First Online:
Handbook of Exoplanets

  • 372 Accesses

Abstract

Stars form in the Galaxy with a wide range in mass. If the mass is below 7% of the Sun’s, then the object does not become hot enough for stable hydrogen burning. These substellar objects are called brown dwarfs. Maps of the sky at infrared wavelengths have found large numbers of brown dwarfs. However only 24 objects have been found (as of April 2017) that are cold enough to be classified as “Y dwarfs”: these have atmospheres that are cooler than 500 K (or ∼200∘C, 400∘F) and have masses only 5–20 times that of Jupiter. The coolest Y dwarf currently known, discovered in 2014, has a temperature around freezing, has a mass of about 5 Jupiter masses, and is only 2 pc away from the Sun. These small and cold objects are faint and difficult to find. This chapter describes the discovery and characterization of the Y dwarfs. Finding more of these very cold planet-like brown dwarfs will require an as-yet unplanned space mission mapping large areas of sky at wavelengths around 5 μm.

This is a preview of subscription content, log in via an institution to check access.

Access this chapter

Log in via an institution
Chapter
USD 29.95
Price excludes VAT (USA)
  • Available as PDF
  • Read on any device
  • Instant download
  • Own it forever
eBook
USD 1,099.99
Price excludes VAT (USA)
  • Available as EPUB and PDF
  • Read on any device
  • Instant download
  • Own it forever
Hardcover Book
USD 1,299.99
Price excludes VAT (USA)
  • Durable hardcover edition
  • Dispatched in 3 to 5 business days
  • Free shipping worldwide - see info

Tax calculation will be finalised at checkout

Purchases are for personal use only

Institutional subscriptions

References

  • Ackerman AS, Marley MS (2001) Precipitating condensation clouds in substellar atmospheres. ApJ 556:872

    Article  ADS  Google Scholar 

  • Baraffe I, Chabrier G, Allard F, Hauschildt PH (2002) Evolutionary models for low-mass stars and brown dwarfs: uncertainties and limits at very young ages. A&A 382:563

    Article  ADS  Google Scholar 

  • Beamin JC, Ivanov VD, Bayo A et al (2014) Temperature constraints on the coldest brown dwarf known: WISE 0855-0714. A&A 570:L8

    Article  ADS  Google Scholar 

  • Bowler BP, Hillenbrand LA (2015) Near-infrared spectroscopy of 2M0441+2301 AabBab: a quadruple system spanning the stellar to planetary mass regimes. ApJ 811:L30

    Article  ADS  Google Scholar 

  • Burgasser AJ, Kirkpatrick JD, Brown ME et al (1999) Discovery of four field methane (T-type) dwarfs with the two micron all-sky survey. ApJ 522:L65

    Article  ADS  Google Scholar 

  • Burrows A, Marley MS, Hubbard WB et al (1997) A nongray theory of extrasolar giant planets and brown dwarfs. ApJ 491:856

    Article  ADS  Google Scholar 

  • Burrows A, Hubbard WB, Lunine JI, Liebert J (2001) The theory of brown dwarfs and extrasolar giant planets. RvMP 73:719

    ADS  Google Scholar 

  • Burrows A, Sudarsky D, Lunine JI (2003) Beyond the T dwarfs: theoretical spectra, colors, and detectability of the coolest brown dwarfs. ApJ 596:587

    Article  ADS  Google Scholar 

  • Cannon AJ, Pickering EC (1912) Classification of 1,477 stars by means of their photographic spectra. AnHar 56:65

    ADS  Google Scholar 

  • Chabrier G (2003) Galactic stellar and substellar initial mass function. PASP 115:763

    Article  ADS  Google Scholar 

  • Cushing MC, Kirkpatrick JD, Gelino CR et al (2011) The discovery of Y dwarfs using data from the wide-field infrared survey explorer (WISE). ApJ 743:50

    Article  ADS  Google Scholar 

  • Cushing MC, Hardegree-Ullman KK, Trucks JL et al (2016) The first detection of photometric variability in a Y dwarf: WISE J140518.39+553421.3. ApJ 823:152

    Article  ADS  Google Scholar 

  • Fazio GG, Hora JL, Allen LE et al (2004) The infrared array camera (IRAC) for the spitzer space telescope. ApJS 154:10

    Article  ADS  Google Scholar 

  • Gehrels N, Spergel D, WFIRST SDT Project (2015) Wide-field infraRed survey telescope (WFIRST) mission and synergies with LISA and LIGO-virgo. J Phys Conf Ser 610:2007

    Google Scholar 

  • Greenhouse MA (2016) The JWST science instrument payload: mission context and status. SPIE 9904:6

    ADS  Google Scholar 

  • Hayashi C, Nakano T (1963) Evolution of stars of small masses in the pre-main-sequence stages. Prog Theor Phys 30:460

    Article  ADS  Google Scholar 

  • Kirkpatrick JD, Reid IN, Liebert J et al (1999) Dwarfs cooler than “M”: the definition of spectral type “L” using discoveries from the 2 micron all-sky survey (2MASS). ApJ 519:802

    Article  ADS  Google Scholar 

  • Kirkpatrick JD, Gelino CR, Cushing MC et al (2012) Further defining spectral type “Y” and exploring the low-mass end of the field brown dwarf mass function. ApJ 753:156

    Article  ADS  Google Scholar 

  • Kroupa P (2001) On the variation of the initial mass function. MNRAS 322:231

    Article  ADS  Google Scholar 

  • Kumar SS (1967) On planets and black dwarfs. Icarus 6:136

    Article  ADS  Google Scholar 

  • Leggett SK, Golimowski DA, Fan X et al (2002) Infrared photometry of late-M, L, and T dwarfs. ApJ 564:452

    Article  ADS  Google Scholar 

  • Leggett SK, Morley CV, Marley et al (2013) A comparison of near-infrared photometry and spectra for Y dwarfs with a new generation of cool cloudy models. ApJ 763:130

    Article  ADS  Google Scholar 

  • Leggett SK, Morley CV, Marley MS, Saumon D (2015) Near-infrared photometry of Y dwarfs: low ammonia abundance and the onset of water clouds. ApJ 799:37

    Article  ADS  Google Scholar 

  • Leggett SK, Cushing MC, Hardegree-Ullman KK et al (2016) Observed variability at 1 and 4 μm in the Y0 brown dwarf WISEP J173835.52+273258.9. ApJ 830:141

    Article  ADS  Google Scholar 

  • Leggett SK, Tremblin P, Esplin TL, Luhman KL, Morley CV (2017) The Y-type brown dwarfs: estimates of mass and age from new astrometry, homogenized photometry, and near-infrared spectroscopy. ApJ 842:118

    Article  ADS  Google Scholar 

  • Li Y, Kouwenhoven MBN, Stamatellos D, Goodwin SP (2015) The dynamical evolution of low-mass hydrogen-burning stars, brown dwarfs, and planetary-mass objects formed through disk fragmentation. ApJ 805:116

    Article  ADS  Google Scholar 

  • Lord SD (1992) A new software tool for computing Earth’s atmospheric transmission of near- and far-infrared radiation. NASA Tech Memo 103957

    Google Scholar 

  • Luhman KL (2014) Discovery of a ∼250 K brown dwarf at 2 pc from the sun. ApJ 786:L18

    Article  ADS  Google Scholar 

  • Mainzer A, Cushing MC, Skrutskie M et al (2011) The first ultra-cool brown dwarf discovered by the wide-field infrared survey explorer. ApJ 726:30

    Article  ADS  Google Scholar 

  • Masiero JR, Mainzer AK, Bauer JM, Grav T, Nugent CR, Stevenson R (2013) Asteroid family identification using the hierarchical clustering method and WISE/NEOWISE physical properties. ApJ 770:7

    Article  ADS  Google Scholar 

  • Miller GE, Scalo JM (1979) The initial mass function and stellar birthrate in the solar neighborhood. ApJS 41:513

    Article  ADS  Google Scholar 

  • Morgan WW, Keenan PC (1973) Spectral classification. ARA&A 11:29

    Article  ADS  Google Scholar 

  • Morley CV, Fortney JJ, Marley MS et al (2012) Neglected clouds in T and Y dwarf atmospheres. ApJ 756:172

    Article  ADS  Google Scholar 

  • Morley CV, Marley MS, Fortney JJ et al (2014) Water clouds in Y dwarfs and exoplanets. ApJ 787:78

    Article  ADS  Google Scholar 

  • Racca GD, Laureijs R, Stagnaro L et al (2016) The Euclid mission design. SPIE 9904:23 pp. https://doi.org/10.1117/12.2230762

  • Salpeter EE (1955) The luminosity function and stellar evolution. ApJ 121:161

    Article  ADS  Google Scholar 

  • Saumon D, Geballe TR, Leggett SK et al (2000) Molecular abundances in the atmosphere of the T dwarf GL 229B. ApJ 541:374

    Article  ADS  Google Scholar 

  • Saumon D, Marley MS (2008) The evolution of L and T dwarfs in color-magnitude diagrams. ApJ 689:1327

    Article  ADS  Google Scholar 

  • Saumon D, Marley MS, Abel M, Frommhold L, Freedman RS (2012) New H2 collision-induced absorption and NH3 opacity and the spectra of the coolest brown dwarfs. ApJ 750:74

    Article  ADS  Google Scholar 

  • Schneider AC, Cushing MC, Kirkpatrick DJ, Gelino CR (2016) The collapse of the wien tail in the coldest brown dwarf? Hubble space telescope near-infrared photometry of WISE J085510.83-071442.5. ApJ 823:35

    Article  ADS  Google Scholar 

  • Showman A, Kaspi Y (2013) Atmospheric dynamics of brown dwarfs and directly imaged giant planets. ApJ 776:85

    Article  ADS  Google Scholar 

  • Spiegel DS, Burrows A (2012) Spectral and photometric diagnostics of giant planet formation scenarios. ApJ 745:174

    Article  ADS  Google Scholar 

  • Stern D, Assef RJ, Benford DJ et al (2012) Mid-infrared selection of active galactic nuclei with the wide-field infrared survey explorer. I. Characterizing WISE-selected active galactic nuclei in COSMOS. ApJ 753:30

    Article  ADS  Google Scholar 

  • Strauss MA, Fan X, Gunn JE et al (1999) The discovery of a field methane dwarf from sloan digital sky survey commissioning data. ApJ 522:L61

    Article  ADS  Google Scholar 

  • Tremblin P, Amundsen DS, Mourier P et al (2015) Fingering convection and cloudless models for cool brown dwarf atmospheres. ApJ 804:L17 (T15)

    Article  ADS  Google Scholar 

  • 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:L29

    ADS  Google Scholar 

  • Warren SJ, Mortlock DJ, Leggett SK et al (2007) A very cool brown dwarf in UKIDSS DR1. MNRAS 381:1400

    Article  ADS  Google Scholar 

  • Wright EL, Eisenhardt PRM, Mainzer AK et al (2010) The wide-field infrared survey explorer (WISE): mission description and initial on-orbit performance. AJ 140:1868

    Article  ADS  Google Scholar 

  • Yurchenko SN, Barber RJ, Tennyson J (2011) A variationally computed line list for hot NH3. MNRAS 413:1828

    Article  ADS  Google Scholar 

  • Yurchenko SN, Tennyson J (2014) ExoMol line lists – IV. The rotation-vibration spectrum of methane up to 1500 K. MNRAS 440:1649

    Article  ADS  Google Scholar 

  • Zahnle KJ, Marley MS (2014) Methane, carbon monoxide, and ammonia in brown dwarfs and self-luminous giant planets. ApJ 797:41

    Article  ADS  Google Scholar 

  • Zapatero Osorio MR, Lodieu N, Bejar VJS et al (2016) Near-infrared photometry of WISE J085510.74-071442.5. A&A 592:80

    Article  ADS  Google Scholar 

  • Zinnecker H, Yorke HW (2007) Toward understanding massive star formation. A&A 45:481

    Article  ADS  Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Gemini Observatory, Northern Operations Center, Hilo, HI, USA

    Sandy K. Leggett

Authors
  1. Sandy K. Leggett
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Sandy K. Leggett .

Editor information

Editors and Affiliations

  1. Instituto de Astrofísica de Canarias, La Laguna, Tenerife, Spain

    Hans J. Deeg

  2. Instituto de Astrofísica de Canarias, La Laguna, Tenerife, Spain

    Juan Antonio Belmonte

Rights and permissions

Reprints and permissions

Copyright information

© 2018 Springer International Publishing AG, part of Springer Nature

About this entry

Check for updates. Verify currency and authenticity via CrossMark

Cite this entry

Leggett, S.K. (2018). Y Dwarfs: The Challenge of Discovering the Coldest Substellar Population in the Solar Neighborhood. In: Deeg, H., Belmonte, J. (eds) Handbook of Exoplanets . Springer, Cham. https://doi.org/10.1007/978-3-319-55333-7_187

Download citation

Publish with us

Policies and ethics

Search

Navigation