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Title: OBSERVED VARIABILITY AT 1 and 4 μ m IN THE Y0 BROWN DWARF WISEP J173835.52+273258.9

Abstract

We have monitored photometrically the Y0 brown dwarf WISEP J173835.52+273258.9 (W1738) at both near- and mid-infrared wavelengths. This ≲1 Gyr old 400 K dwarf is at a distance of 8 pc and has a mass around 5 M {sub Jupiter}. We observed W1738 using two near-infrared filters at λ ≈ 1 μ m, Y and J , on Gemini Observatory and two mid-infrared filters at λ ≈ 4 μ m, [3.6] and [4.5], on the Spitzer observatory. Twenty-four hours were spent on the source by Spitzer on each of 2013 June 30 and October 30 UT. Between these observations, around 5 hr were spent on the source by Gemini on each of 2013 July 17 and August 23 UT. The mid-infrared light curves show significant evolution between the two observations separated by 4 months. We find that a double sinusoid can be fit to the [4.5] data, where one sinusoid has a period of 6.0 ± 0.1 hr and the other a period of 3.0 ± 0.1 hr. The near-infrared observations suggest variability with a ∼3.0 hr period, although only at a ≲2 σ confidence level. We interpret our results as showing that the Y dwarf has a 6.0 ±more » 0.1 hr rotation period, with one or more large-scale surface features being the source of variability. The peak-to-peak amplitude of the light curve at [4.5] is 3%. The amplitude of the near-infrared variability, if real, may be as high as 5%–30%. Intriguingly, this size of variability and the wavelength dependence can be reproduced by atmospheric models that include patchy KCl and Na{sub 2}S clouds and associated small changes in surface temperature. The small number of large features, as well as the timescale for evolution of the features, is very similar to what is seen in the atmospheres of the solar system gas giants.« less

Authors:
 [1]; ; ;  [2];  [3]; ;  [4];  [5];  [6]; ;  [7];  [8];  [9]
  1. Gemini Observatory, Northern Operations Center, 670 N. A’ohoku Place, Hilo, HI 96720 (United States)
  2. The University of Toledo, 2801 West Bancroft Street, Mailstop 111, Toledo, OH 43606 (United States)
  3. NASA Ames Research Center, Mail Stop 245-3, Moffett Field, CA 94035 (United States)
  4. Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States)
  5. Los Alamos National Laboratory, P.O. Box 1663, MS F663, Los Alamos, NM 87545 (United States)
  6. Spitzer Science Center, CalTech, Pasadena, CA 91125 (United States)
  7. IPAC, CalTech, Pasadena, CA 91125 (United States)
  8. University of Delaware, Newark, DE 19716 (United States)
  9. University of Texas, Austin, TX 78712 (United States)
Publication Date:
OSTI Identifier:
22667308
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 830; Journal Issue: 2; 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; AMPLITUDES; ATMOSPHERES; CLOUDS; DWARF STARS; FILTERS; FREQUENCY DEPENDENCE; MASS; POTASSIUM CHLORIDES; ROTATION; SODIUM SULFIDES; SOLAR SYSTEM; STAR EVOLUTION; STARS; SURFACES; VISIBLE RADIATION; WAVELENGTHS

Citation Formats

Leggett, S. K., Cushing, Michael C., Hardegree-Ullman, Kevin K., Trucks, Jesica L., Marley, M. S., Morley, Caroline V., Fortney, J. J., Saumon, D., Carey, S. J., Gelino, C. R., Kirkpatrick, J. D., Gizis, J. E., and Mace, G. N., E-mail: sleggett@gemini.edu. OBSERVED VARIABILITY AT 1 and 4 μ m IN THE Y0 BROWN DWARF WISEP J173835.52+273258.9. United States: N. p., 2016. Web. doi:10.3847/0004-637X/830/2/141.
Leggett, S. K., Cushing, Michael C., Hardegree-Ullman, Kevin K., Trucks, Jesica L., Marley, M. S., Morley, Caroline V., Fortney, J. J., Saumon, D., Carey, S. J., Gelino, C. R., Kirkpatrick, J. D., Gizis, J. E., & Mace, G. N., E-mail: sleggett@gemini.edu. OBSERVED VARIABILITY AT 1 and 4 μ m IN THE Y0 BROWN DWARF WISEP J173835.52+273258.9. United States. doi:10.3847/0004-637X/830/2/141.
Leggett, S. K., Cushing, Michael C., Hardegree-Ullman, Kevin K., Trucks, Jesica L., Marley, M. S., Morley, Caroline V., Fortney, J. J., Saumon, D., Carey, S. J., Gelino, C. R., Kirkpatrick, J. D., Gizis, J. E., and Mace, G. N., E-mail: sleggett@gemini.edu. Thu . "OBSERVED VARIABILITY AT 1 and 4 μ m IN THE Y0 BROWN DWARF WISEP J173835.52+273258.9". United States. doi:10.3847/0004-637X/830/2/141.
@article{osti_22667308,
title = {OBSERVED VARIABILITY AT 1 and 4 μ m IN THE Y0 BROWN DWARF WISEP J173835.52+273258.9},
author = {Leggett, S. K. and Cushing, Michael C. and Hardegree-Ullman, Kevin K. and Trucks, Jesica L. and Marley, M. S. and Morley, Caroline V. and Fortney, J. J. and Saumon, D. and Carey, S. J. and Gelino, C. R. and Kirkpatrick, J. D. and Gizis, J. E. and Mace, G. N., E-mail: sleggett@gemini.edu},
abstractNote = {We have monitored photometrically the Y0 brown dwarf WISEP J173835.52+273258.9 (W1738) at both near- and mid-infrared wavelengths. This ≲1 Gyr old 400 K dwarf is at a distance of 8 pc and has a mass around 5 M {sub Jupiter}. We observed W1738 using two near-infrared filters at λ ≈ 1 μ m, Y and J , on Gemini Observatory and two mid-infrared filters at λ ≈ 4 μ m, [3.6] and [4.5], on the Spitzer observatory. Twenty-four hours were spent on the source by Spitzer on each of 2013 June 30 and October 30 UT. Between these observations, around 5 hr were spent on the source by Gemini on each of 2013 July 17 and August 23 UT. The mid-infrared light curves show significant evolution between the two observations separated by 4 months. We find that a double sinusoid can be fit to the [4.5] data, where one sinusoid has a period of 6.0 ± 0.1 hr and the other a period of 3.0 ± 0.1 hr. The near-infrared observations suggest variability with a ∼3.0 hr period, although only at a ≲2 σ confidence level. We interpret our results as showing that the Y dwarf has a 6.0 ± 0.1 hr rotation period, with one or more large-scale surface features being the source of variability. The peak-to-peak amplitude of the light curve at [4.5] is 3%. The amplitude of the near-infrared variability, if real, may be as high as 5%–30%. Intriguingly, this size of variability and the wavelength dependence can be reproduced by atmospheric models that include patchy KCl and Na{sub 2}S clouds and associated small changes in surface temperature. The small number of large features, as well as the timescale for evolution of the features, is very similar to what is seen in the atmospheres of the solar system gas giants.},
doi = {10.3847/0004-637X/830/2/141},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 830,
place = {United States},
year = {2016},
month = {10}
}