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An Improved Near-infrared Spectrum of the Archetype Y Dwarf WISEP J182831.08+265037.8

Cushing, Michael C. and Schneider, Adam C. and Kirkpatrick, J. Davy and Morley, Caroline V. and Marley, Mark S. and Gelino, Christopher R. and Mace, Gregory N. and Wright, Edward L. and Eisenhardt, Peter R. and Skrutskie, Michael F. and Marsh, Kenneth A. (2021) An Improved Near-infrared Spectrum of the Archetype Y Dwarf WISEP J182831.08+265037.8. Astrophysical Journal, 920 (1). Art. No. 20. ISSN 0004-637X. doi:10.3847/1538-4357/ac12cb.

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We present a Hubble Space Telescope/Wide-Field Camera 3 near-infrared spectrum of the archetype Y dwarf WISEP 182831.08+265037.8. The spectrum covers the 0.9–1.7 μm wavelength range at a resolving power of λ/Δλ ≈ 180 and is a significant improvement over the previously published spectrum because it covers a broader wavelength range and is uncontaminated by light from a background star. The spectrum is unique for a cool brown dwarf in that the flux peaks in the Y, J, and H bands are of near equal intensity in units of f_λ. We fail to detect any absorption bands of NH3 in the spectrum, in contrast to the predictions of chemical equilibrium models, but tentatively identify CH₄ as the carrier of an unknown absorption feature centered at 1.015 μm. Using previously published ground- and spaced-based photometry, and using a Rayleigh–Jeans tail to account for flux emerging longward of 4.5 μm, we compute a bolometric luminosity of log (L_(bol)/L_⊙^N)) = -6.50 ± 0.02, which is significantly lower than previously published results. Finally, we compare the spectrum and photometry to two sets of atmospheric models and find that the best overall match to the observed properties of WISE 1828+2650 is a ∼1 Gyr old binary composed of two T_(eff) ∼ 325 K, ∼5 M_(Jup) brown dwarfs with subsolar [C/O] ratios.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper ItemY Dwarf Compendium
Cushing, Michael C.0000-0001-7780-3352
Schneider, Adam C.0000-0002-6294-5937
Kirkpatrick, J. Davy0000-0003-4269-260X
Morley, Caroline V.0000-0002-4404-0456
Marley, Mark S.0000-0002-5251-2943
Mace, Gregory N.0000-0001-7875-6391
Wright, Edward L.0000-0001-5058-1593
Skrutskie, Michael F.0000-0001-8671-5901
Marsh, Kenneth A.0000-0003-0107-7803
Additional Information:© 2021. The American Astronomical Society. Received 2021 January 12; revised 2021 June 24; accepted 2021 June 28; published 2021 October 8. This research is based on observations made with the NASA/ESA Hubble Space Telescope obtained from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 526555. These observations are associated with program 12970. This publication makes use of data products from the Wide-field Infrared Survey Explorer, which is a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory/California Institute of Technology, and NEOWISE, which is a project of the Jet Propulsion Laboratory/California Institute of Technology. WISE and NEOWISE are funded by the National Aeronautics and Space Administration. This research has benefited from the Y Dwarf Compendium maintained by Michael Cushing at Facilities: HST (WFC3) - , Spitzer (IRAC). - Software: IDL.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
NASANAS 5-26555
Subject Keywords:Near infrared astronomy; Y dwarfs; Spectroscopy; Brown dwarfs
Issue or Number:1
Classification Code:Unified Astronomy Thesaurus concepts: Near infrared astronomy (1093); Y dwarfs (1827); Spectroscopy (1558); Brown dwarfs (185)
Record Number:CaltechAUTHORS:20211015-190201265
Persistent URL:
Official Citation:Michael C. Cushing et al 2021 ApJ 920 20
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:111471
Deposited By: George Porter
Deposited On:18 Oct 2021 17:53
Last Modified:18 Oct 2021 17:53

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