J/ApJ/958/94 Keck/NIRES spectrum for CWISE J105512.11+544328.3 (Robbins+, 2023)
CWISE J105512.11+544328.3: a nearby Y dwarf spectroscopically confirmed with
Keck/NIRES.
Robbins G., Meisner A.M., Schneider A.C., Burgasser A.J.,
Kirkpatrick J.D., Gagne J., Hsu C.-C., Moranta L., Casewell S.,
Marocco F., Gerasimov R., Faherty J.K., Kuchner M.J., Caselden D.,
Cushing M.C., Alejandro S., The Backyard Worlds: Planet 9 Collaboration,
The Backyard Worlds: Cool Neighbors Collaboration
<Astrophys. J., 958, 94 (2023)>
=2023ApJ...958...94R 2023ApJ...958...94R
ADC_Keywords: Stars, Y-type; Stars, brown dwarf; Spectra, infrared
Keywords: Y dwarfs ; T dwarfs ; Brown dwarfs ; Near infrared astronomy
Abstract:
Y dwarfs, the coolest known spectral class of brown dwarfs, overlap in
mass and temperature with giant exoplanets, providing unique
laboratories for studying low-temperature atmospheres. However, only a
fraction of Y dwarf candidates have been spectroscopically confirmed.
We present Keck/NIRES near-infrared spectroscopy of the nearby
(d∼6-8pc) brown dwarf CWISE J105512.11+544328.3. Although its
near-infrared spectrum aligns best with the Y0 standard in the J band,
no standard matches well across the full YJHK wavelength range. The
CWISE J105512.11+544328.3 NH3-H=0.427±0.0012 and
CH4-J=0.0385±0.0007 absorption indices and absolute Spitzer [4.5]
magnitude of 15.18±0.22 are also indicative of an early-Y dwarf
rather than a late-T dwarf. CWISE J105512.11+544328.3 additionally
exhibits the bluest Spitzer [3.6]-[4.5] color among all
spectroscopically confirmed Y dwarfs. Despite this anomalously blue
Spitzer color given its low luminosity, CWISE J105512.11+544328.3 does
not show other clear kinematic or spectral indications of low
metallicity. Atmospheric model comparisons yield a log(g)≤4.5 and
Teff∼500±150K for this source. We classify CWISE J105512.11+544328.3
as a Y0 (pec) dwarf, adding to the remarkable diversity of the Y-type
population. JWST spectroscopy would be crucial to understanding the
origin of this Y dwarf's unusual preference for low-gravity models and
blue 3-5µm color.
Description:
We used the Near-Infrared Echellette Spectrometer (NIRES; R∼2700) on
the Keck II telescope on 2021 February 24 (UT) to obtain 0.94-2.45um
near-infrared spectra of CWISE J105512.11+544328.3.
See Section 2.3.
Objects:
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RA (ICRS) DE Designation(s)
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10 55 14.78 +54 43 31.9 CWISE J105512.11+544328.3 = EQ J1055+5443
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 237 1 WISE J105512.11+544328.3 properties and photometry
sp/* . 1 *The reduced Keck/NIRES near-infrared spectrum for
CWISE J105512.11+544328.3 in FITS format
(Data behind Figure 5)
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Note on sp/*: The wavelengths of the reduced spectrum are accessed in the
first row of the FITS image array in units of microns. The fluxes of
the reduced spectrum are accessed in the second row of the image array
in units of ergs per second per square centimeter per angstrom. The
uncertainties of the reduced spectrum are accessed in the third row of
the image array in units of ergs per second per square centimeter per
angstrom. The fourth row of the image array is empty and should be
ignored.
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See also:
II/328 : AllWISE Data Release (Cutri+ 2013)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
II/365 : The CatWISE2020 catalog (updated version 28-Jan-2021) (Marocco+, 2021)
I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)
J/AJ/127/2856 : Brown dwarfs in the 2MASS Survey (Burgasser+, 2004)
J/ApJ/637/1067 : Near-IR spectral classification of T dwarfs (Burgasser+, 2006)
J/AJ/137/1 : PMs and astrometry of late-type dwarfs (Faherty+, 2009)
J/ApJS/190/100 : NIR proper motion survey using 2MASS (Kirkpatrick+, 2010)
J/ApJS/197/19 : First brown dwarfs discovered by WISE (Kirkpatrick+, 2011)
J/AJ/144/148 : Infrared phot. of brown dwarf and Hyper-LIRG (Griffith+, 2012)
J/ApJ/753/156 : T/Y brown dwarfs with WISE photometry (Kirkpatrick+, 2012)
J/ApJS/205/6 : T dwarf population revealed by WISE (Mace+, 2013)
J/ApJ/794/143 : New SpeX Observations of M7-L6 Dwarfs (Bardalez+, 2014)
J/ApJ/810/158 : M,L,T dwarfs fundamental param. and SEDs (Filippazzo+, 2015)
J/ApJ/842/118 : Brown dwarfs with spectral type later than T6 (Leggett+, 2017)
J/ApJ/856/23 : BANYAN. XI. The BANYAN Σ algorithm (Gagne+, 2018)
J/ApJS/240/19 : Parallaxes of late-T and Y dwarfs (Kirkpatrick+, 2019)
J/ApJ/903/96 : The µTau Association (MUTA) (Gagne+, 2020)
J/ApJ/889/74 : Spitzer follow-up of Y brown dwarfs (Meisner+, 2020)
J/AJ/160/63 : IR sp. of 5 brown dwarfs with Gemini North IRS (Miles+, 2020)
J/ApJ/920/20 : HST/WFC3 sp. of WISEP J182831.08+265037.8 (Cushing+, 2021)
J/ApJS/253/7 : A full-sky census of BDs within 20pc (Kirkpatrick+, 2021)
J/ApJ/918/11 : Infrared photometry of late-type brown dwarfs (Leggett+, 2021)
J/ApJ/939/94 : New assoc. in Gaia DR3 solar neighborhood (Moranta+, 2022)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 7 F7.1 mas/yr pmRA [-1518.7] Proper motion in right ascension
direction (pmRA*cosDE) (1)
9- 11 F3.1 mas/yr e_pmRA [2.1] pmRA uncertainty
13- 18 F6.1 mas/yr pmDE [-222.7] Proper motion in declination
direction (1)
20- 22 F3.1 mas/yr e_pmDE [2] pmDE uncertainty
24- 29 F6.1 mas/yr muTot [1534.9] Total proper motion (1)
31- 33 F3.1 mas/yr e_muTot [2.9] muTot uncertainty
35- 39 F5.1 mas plx [145] Parallax (1)
41- 44 F4.1 mas e_plx [14.7] Parallax uncertainty
46- 49 F4.1 km/s Vtan [50.2] Tangential velocity; this work
51- 53 F3.1 km/s e_Vtan [5.2] Vtan uncertainty
55- 62 A8 --- SpT Spectral type; this work
64- 66 F3.1 --- e_SpT [0.5] SpT uncertainty
68- 70 I3 K Teff [500] Effective temperature; this work
72- 74 I3 K e_Teff [150] Teff uncertainty
76- 77 A2 --- l_logg [≤] Limit flag on logg
78- 80 F3.1 [cm/s2] logg Log of surface gravity; this work
82- 87 F6.3 mag JMKO [18.868] MKO J-band magnitude; this work
(see Section 2.2)
89- 93 F5.3 mag e_JMKO [0.066] JMKO uncertainty
95 A1 --- l_Jmag Limit flag on Jmag
96- 100 F5.2 mag Jmag J-band magnitude (1)
102 A1 --- l_Hmag Limit flag on Hmag
103- 107 F5.2 mag Hmag H-band magnitude (1)
109 A1 --- l_Ksmag Limit flag on Ksmag
110- 114 F5.2 mag Ksmag Ks-band magnitude (1)
116- 121 F6.3 mag W1catW [17.332] CatWISE (II/365) W1 magnitude
123- 127 F5.3 mag e_W1catW [0.082] W1catW uncertainty
129- 134 F6.3 mag W2catW [14.371] CatWISE (II/365) W2 magnitude
136- 140 F5.3 mag e_W2catW [0.018] W2catW uncertainty
142- 147 F6.3 mag W1mag [17.306] AllWISE W1 (3.4um) band magnitude
149- 153 F5.3 mag e_W1mag [0.127] Uncertainty on the W1mag
155- 160 F6.3 mag W2mag [14.366] AllWISE W2 (4.6um) band magnitude
162- 166 F5.3 mag e_W2mag [0.044] Uncertainty on the W2mag
168- 173 F6.3 mag W3mag [11.553] AllWISE W3 (12um) band magnitude
175- 179 F5.3 mag e_W3mag [0.196] Uncertainty on the W3mag
181- 186 F6.3 mag ch1mag [16.219] Spitzer ch1 (3.6um) band magnitude (1)
188- 192 F5.3 mag e_ch1mag [0.033] Uncertainty on the ch1mag
194- 199 F6.3 mag ch2mag [14.376] Spitzer ch2 (4.5um) band magnitude (1)
201- 205 F5.3 mag e_ch2mag [0.019] Uncertainty on the ch2mag
207- 237 A31 --- File Name of the FITS file in subdirectory "sp"
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Note (1): From Kirkpatrick+ 2021, J/ApJS/253/7
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History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 23-Jan-2026