J/AJ/168/66 NIR spectrum of the red L/T VHS J183135.58-551355.9 (Bickle+, 2024)
Discovery of the remarkably red L/T transition object VHS J183135.58-551355.9.
Bickle T.P., Schneider A.C., Gagne J., Faherty J.K., Rothermich A.,
Vos J.M., Suarez G., Kirkpatrick J.D., Meisner A.M., Kuchner M.J.,
Burgasser A.J., Marocco F., Casewell S.L., Caselden D.,
Bardalez Gagliuffi D.C., The Backyard Worlds: Planet 9 Collaboration
<Astron. J., 168, 66 (2024)>
=2024AJ....168...66B 2024AJ....168...66B
ADC_Keywords: Stars, brown dwarf; Spectra, infrared; Spectral types;
Stars, distances; Photometry, infrared; Stars, L-type;
Stars, T-type; Proper motions
Keywords: Brown dwarfs ; L dwarfs ; T dwarfs ; Stellar associations ;
Moving clusters
Abstract:
We present the discovery of VHS J183135.58-551355.9, an L/T transition
dwarf identified as a result of its unusually red near-infrared colors
(J-KS=3.633±0.277mag; J-W2=6.249±0.245mag) from the VISTA
Hemisphere Survey and CatWISE2020 surveys. We obtain low-resolution
near-infrared spectroscopy of VHS J1831-5513 using the Magellan Folded
port InfraRed Echellette spectrograph to confirm its extremely red
nature and assess features sensitive to surface gravity (i.e., youth).
Its near-infrared spectrum shows multiple CH4 absorption features,
indicating an exceptionally low effective temperature for its spectral
type. Based on proper-motion measurements from CatWISE2020 and a
photometric distance derived from its Ks-band magnitude, we find that
VHS J1831-5513 is a likely (∼85% probability) kinematic member of the
β Pictoris moving group. Future radial velocity and trigonometric
parallax measurements will clarify such membership. Follow-up
mid-infrared or higher-resolution near-infrared spectroscopy of this
object will allow for further investigation as to the cause(s) of its
redness, such as youth, clouds, and viewing geometry.
Description:
We used the 6.5m Magellan Baade telescope and the FIRE spectrograph to
obtain near-infrared spectra for VHS J183135.58-551355.9. Observations
were made on 2023 June 30 under clear conditions. We operated FIRE in
the low-resolution prism mode using the 0.8" slit (resolution
λ/Δλ∼100) covering the full 0.8-2.5um wavelength
range. The final reduced spectrum is shown in Figure 1. See Section 3.
Objects:
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RA (ICRS) DE Designation(s)
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18 31 35.58 -55 13 55.9 VHS J1831-5513 = VHS J183135.58-551355.9
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 129 1 Properties of VHS J1831-5513
sp/* . 1 The Magellan/FIRE spectrum of VHS J1831-5513
in FITS format
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See also:
II/319 : UKIDSS-DR9 LAS, GCS and DXS Surveys (Lawrence+ 2012)
II/367 : The VISTA Hemisphere Survey (VHS) catalog DR5 (McMahon+, 2020)
II/365 : CatWISE2020 catalog (updated version 28-Jan-2021) (Marocco+, 2021)
VII/233 : 2MASS All-Sky Extended Source Catalog (XSC) (IPAC/UMass, 2003-2006)
J/ApJ/564/421 : Spectra of T dwarfs. I. (Burgasser+, 2002)
J/other/ARA+A/42.685 : Young stars near the Sun (Zuckerman+, 2004)
J/other/ARA+A/43.195 : L and T dwarf stars (Kirkpatrick, 2005)
J/ApJ/637/1067 : NIR 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/201/19 : Hawaii Infrared Parallax Program. I. (Dupuy+, 2012)
J/ApJ/752/56 : BDKP. III. Plx for 70 ultracool dwarfs (Faherty+, 2012)
J/ApJ/762/88 : Young stellar kinematic group cand. members (Malo+, 2013)
J/ApJ/783/121 : BANYAN II. Nearby young assoc. cand. members (Gagne+, 2014)
J/AJ/147/34 : SpeX library of L-type dwarfs (Schneider+, 2014)
J/MNRAS/454/593 : Young moving groups in solar neighbourhood (Bell+, 2015)
J/ApJ/810/158 : M,L,T dwarfs fundamental param. and SEDs (Filippazzo+, 2015)
J/ApJS/219/33 : BANYAN. VII. Candidate YMG members from BASS (Gagne+, 2015)
J/ApJS/225/10 : Kinematic analysis of M7-L8 dwarfs (Faherty+, 2016)
J/ApJ/833/96 : Hawaii infrared plx prog. II. Ultracool dwarfs (Liu+, 2016)
J/ApJ/838/73 : BD surface gravities with Keck/NIRSPEC (Martin , 2017)
J/AJ/154/69 : ACRONYM II. β Pictoris Moving Group (Shkolnik+, 2017)
J/AJ/155/34 : Analysis of NIR sp. of neighboring L dwarfs (Cruz+, 2018)
J/ApJ/856/23 : BANYAN. XI. The BANYAN Σ algorithm (Gagne+, 2018)
J/A+A/629/A145 : L9-T3.5 brown dwarfs light curves (Eriksson+, 2019)
J/AJ/160/38 : Spitzer variability detections of brown dwarfs (Vos+, 2020)
J/ApJ/923/48 : Discovery of an L dwarf co-moving BD+601417 (Faherty+, 2021)
J/ApJS/253/7 : A full-sky census of BDs within 20pc (Kirkpatrick+, 2021)
J/ApJ/920/99 : Ultracool Dwarfs with Spitzer IR Sp. I. (Suarez+, 2021)
J/ApJ/934/178 : L/T transition BDs from NIR SpeX spectra (Ashraf+, 2022)
J/MNRAS/513/5701 : Silicate clouds in ultracool dwarfs (Suarez+, 2022)
J/AJ/164/239 : IR LC of VHS1256-1257b in 2018 & 2020 epochs (Zhou+, 2022)
J/AJ/166/103 : UKIRT Hemisphere Survey L, T & Y dwarfs (Schneider+, 2023)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 10 F10.6 deg RAdeg Right ascension (J2000) (1)
12- 21 F10.6 deg DEdeg Declination (J2000) (1)
23- 26 F4.2 mas/yr pmRA [1.43] Proper motion in right ascension (2)
28- 30 F3.1 mas/yr e_pmRA [9.6] pmRA uncertainty
32- 37 F6.2 mas/yr pmDE [-84.24] Proper motion in declination (2)
39- 42 F4.1 mas/yr e_pmDE [10.4] pmDE uncertainty
44- 49 F6.3 mag Jmag [20.175] VISTA/VIRCAM J-band magnitude (1)
51- 55 F5.3 mag e_Jmag [0.229] Uncertainty on the Jmag
57- 62 F6.3 mag Ksmag [16.542] VISTA/VIRCAM Ks-band magnitude (1)
64- 68 F5.3 mag e_Ksmag [0.048] Uncertainty on the Ksmag
70- 75 F6.3 mag W1mag [14.735] WISE W1 (3.4um) band
magnitude (2)
77- 81 F5.3 mag e_W1mag [0.018] Uncertainty on the W1mag
83- 88 F6.3 mag W2mag [13.926] WISE W2 (4.6um) band
magnitude (2)
90- 94 F5.3 mag e_W2mag [0.016] Uncertainty on the W2mag
96- 99 F4.1 pc Dist [55.4] Photometric distance from this work (3)
101- 103 F3.1 pc e_Dist [5.5] Dist uncertainty
105- 119 A15 --- SpT Spectral type (NIR) from this work
121- 129 A9 --- File Name of the FITS file in subdirectory "sp"
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Note (1): Positions and J, Ks magnitudes from VHS DR6 (McMahon+ 2013;
see II/367).
Note (2): Proper motions and WISE magnitudes from the CatWISE2020 Reject Table
(Marocco+ 2021, II/365). Proper-motion values corrected for CatWISE2020
systematic offsets.
Note (3): Photometric distance estimated using the VHS KS magnitude and the
absolute magnitude-spectral type relation of Dupuy & Liu (2012, J/ApJS/201/19).
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History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 30-Sep-2024