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Title: THE DISCOVERY OF Y DWARFS USING DATA FROM THE WIDE-FIELD INFRARED SURVEY EXPLORER (WISE)

Abstract

We present the discovery of seven ultracool brown dwarfs identified with the Wide-field Infrared Survey Explorer (WISE). Near-infrared spectroscopy reveals deep absorption bands of H{sub 2}O and CH{sub 4} that indicate all seven of the brown dwarfs have spectral types later than UGPS J072227.51-054031.2, the latest-type T dwarf currently known. The spectrum of WISEP J182831.08+265037.8 is distinct in that the heights of the J- and H-band peaks are approximately equal in units of f{sub {lambda}}, so we identify it as the archetypal member of the Y spectral class. The spectra of at least two of the other brown dwarfs exhibit absorption on the blue wing of the H-band peak that we tentatively ascribe to NH{sub 3}. These spectral morphological changes provide a clear transition between the T dwarfs and the Y dwarfs. In order to produce a smooth near-infrared spectral sequence across the T/Y dwarf transition, we have reclassified UGPS 0722-05 as the T9 spectral standard and tentatively assign WISEP J173835.52+273258.9 as the Y0 spectral standard. In total, six of the seven new brown dwarfs are classified as Y dwarfs: four are classified as Y0, one is classified as Y0 (pec?), and WISEP J1828+2650 is classified as >Y0. We havemore » also compared the spectra to the model atmospheres of Marley and Saumon and infer that the brown dwarfs have effective temperatures ranging from 300 K to 500 K, making them the coldest spectroscopically confirmed brown dwarfs known to date.« less

Authors:
; ;  [1]; ; ; ; ;  [2];  [3];  [4];  [5];  [6]; ;  [7];  [8]
  1. Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, MS 321-520, Pasadena, CA 91109 (United States)
  2. Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States)
  3. Department of Astronomy, University of Virginia, Charlottesville, VA 22904 (United States)
  4. Center for Astrophysics and Space Science, University of California San Diego, La Jolla, CA 92093 (United States)
  5. Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States)
  6. Massachusetts Institute of Technology, 77 Massachusetts Avenue, Building 37, Cambridge, MA 02139 (United States)
  7. NASA Ames Research Center, MS 254-3, Moffett Field, CA 94035 (United States)
  8. Los Alamos National Laboratory, MS F663, Los Alamos, NM 87545 (United States)
Publication Date:
OSTI Identifier:
22004514
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 743; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION; ABSORPTION SPECTROSCOPY; AMMONIA; INFRARED SPECTRA; INFRARED SURVEYS; METHANE; MORPHOLOGICAL CHANGES; STARS; STELLAR ATMOSPHERES; WATER

Citation Formats

Cushing, Michael C, Mainzer, A, Eisenhardt, Peter R, Kirkpatrick, J Davy, Gelino, Christopher R, Griffith, Roger L, Marsh, Kenneth A, Beichman, Charles A, Skrutskie, Michael F, Burgasser, Adam J, Prato, Lisa A, Simcoe, Robert A, Marley, Mark S, Freedman, Richard S, Saumon, D, and Wright, Edward L., E-mail: michael.cushing@gmail.com. THE DISCOVERY OF Y DWARFS USING DATA FROM THE WIDE-FIELD INFRARED SURVEY EXPLORER (WISE). United States: N. p., 2011. Web. doi:10.1088/0004-637X/743/1/50.
Cushing, Michael C, Mainzer, A, Eisenhardt, Peter R, Kirkpatrick, J Davy, Gelino, Christopher R, Griffith, Roger L, Marsh, Kenneth A, Beichman, Charles A, Skrutskie, Michael F, Burgasser, Adam J, Prato, Lisa A, Simcoe, Robert A, Marley, Mark S, Freedman, Richard S, Saumon, D, & Wright, Edward L., E-mail: michael.cushing@gmail.com. THE DISCOVERY OF Y DWARFS USING DATA FROM THE WIDE-FIELD INFRARED SURVEY EXPLORER (WISE). United States. https://doi.org/10.1088/0004-637X/743/1/50
Cushing, Michael C, Mainzer, A, Eisenhardt, Peter R, Kirkpatrick, J Davy, Gelino, Christopher R, Griffith, Roger L, Marsh, Kenneth A, Beichman, Charles A, Skrutskie, Michael F, Burgasser, Adam J, Prato, Lisa A, Simcoe, Robert A, Marley, Mark S, Freedman, Richard S, Saumon, D, and Wright, Edward L., E-mail: michael.cushing@gmail.com. 2011. "THE DISCOVERY OF Y DWARFS USING DATA FROM THE WIDE-FIELD INFRARED SURVEY EXPLORER (WISE)". United States. https://doi.org/10.1088/0004-637X/743/1/50.
@article{osti_22004514,
title = {THE DISCOVERY OF Y DWARFS USING DATA FROM THE WIDE-FIELD INFRARED SURVEY EXPLORER (WISE)},
author = {Cushing, Michael C and Mainzer, A and Eisenhardt, Peter R and Kirkpatrick, J Davy and Gelino, Christopher R and Griffith, Roger L and Marsh, Kenneth A and Beichman, Charles A and Skrutskie, Michael F and Burgasser, Adam J and Prato, Lisa A and Simcoe, Robert A and Marley, Mark S and Freedman, Richard S and Saumon, D and Wright, Edward L., E-mail: michael.cushing@gmail.com},
abstractNote = {We present the discovery of seven ultracool brown dwarfs identified with the Wide-field Infrared Survey Explorer (WISE). Near-infrared spectroscopy reveals deep absorption bands of H{sub 2}O and CH{sub 4} that indicate all seven of the brown dwarfs have spectral types later than UGPS J072227.51-054031.2, the latest-type T dwarf currently known. The spectrum of WISEP J182831.08+265037.8 is distinct in that the heights of the J- and H-band peaks are approximately equal in units of f{sub {lambda}}, so we identify it as the archetypal member of the Y spectral class. The spectra of at least two of the other brown dwarfs exhibit absorption on the blue wing of the H-band peak that we tentatively ascribe to NH{sub 3}. These spectral morphological changes provide a clear transition between the T dwarfs and the Y dwarfs. In order to produce a smooth near-infrared spectral sequence across the T/Y dwarf transition, we have reclassified UGPS 0722-05 as the T9 spectral standard and tentatively assign WISEP J173835.52+273258.9 as the Y0 spectral standard. In total, six of the seven new brown dwarfs are classified as Y dwarfs: four are classified as Y0, one is classified as Y0 (pec?), and WISEP J1828+2650 is classified as >Y0. We have also compared the spectra to the model atmospheres of Marley and Saumon and infer that the brown dwarfs have effective temperatures ranging from 300 K to 500 K, making them the coldest spectroscopically confirmed brown dwarfs known to date.},
doi = {10.1088/0004-637X/743/1/50},
url = {https://www.osti.gov/biblio/22004514}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 1,
volume = 743,
place = {United States},
year = {Sat Dec 10 00:00:00 EST 2011},
month = {Sat Dec 10 00:00:00 EST 2011}
}