J/AJ/166/5 7 white dwarfs systems J-, H-, and K-band spectroscopy (Owens+, 2023)
Disk or Companion; Characterizing Excess Infrared Flux in Seven White Dwarf
Systems with Near-infrared Spectroscopy.
Owens D., Xu S., Manjavacas E., Leggett S.K., Casewell S.L., Dennihy E.,
Dufour P., Klein B.L., Yeh S., Zuckerman B.
<Astron. J., 166, 5 (2023)>
=2023AJ....166....5O 2023AJ....166....5O
ADC_Keywords: Stars, white dwarf; Spectra, infrared
Keywords: Infrared spectroscopy ; Infrared excess ; Brown dwarfs ; White
dwarf stars ; Debris disks
Abstract:
Excess infrared flux from white dwarf stars is likely to arise from a
dusty debris disk or a cool companion. In this work, we present
near-infrared spectroscopic observations with Keck/MOSFIRE,
Gemini/GNIRS, and Gemini/Flamingos-2 of seven white dwarfs with
infrared excesses identified in previous studies. We confirmed the
presence of dust disks around four white dwarfs (GaiaJ0611-6931,
GaiaJ0006+2858, GaiaJ2100+2122, and WD0145+234) as well as two new
white dwarf-brown dwarf pairs (GaiaJ0052+4505 and GaiaJ0603+4518). In
three of the dust disk systems, we detected for the first time
near-infrared metal emissions (MgI, SiI, and possibly FeI) from a
gaseous component of the disk. We developed a new Markov Chain Monte
Carlo framework to constrain the geometric properties of each dust
disk. In three systems, the dust disk and the gas disk appear to
coincide spatially. For the two brown dwarf-white dwarf pairs, we
identified broad molecular absorption features typically seen in L
dwarfs. The origin of the infrared excess around GaiaJ0723+6301
remains a mystery. Our study underlines how near-infrared spectroscopy
can be used to determine sources of infrared excess around white
dwarfs, which has now been detected photometrically in hundreds of
systems.
Description:
We used the MOSFIRE multi-object near-infrared spectrograph, installed
at the Keck I telescope to observe Gaia J0006+2858, Gaia J0052+4505,
WD 0145+4505, Gaia J0603+4518, and Gaia J2100+2122 (660≤R≤40000
between 0.32 and 2.65um). Gaia J0603+4518 and Gaia J0723+6301 were
observed with Gemini/GNIRS via the program GN-2021B-Q-325. The short
blue camera was used with the 32l/mm grating in the cross-dispersed
mode, which provides a continuous wavelength coverage of 0.8-2.5um. We
used a 1.0" wide slit.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 180 7 White dwarf parameters
f6.dat 17 4683 Gaia J0006+2858 MOSFIRE J, H, K band Spectroscopy
f52.dat 17 4668 Gaia J0052+4505 MOSFIRE J, H, K band Spectroscopy
f603g.dat 17 3271 Gaia J0603+4518 GNIRS 0.8-2.5um Spectroscopy
f603m.dat 17 3175 Gaia J0603+4518 MOSFIRE H, K band Spectroscopy
f611.dat 17 1430 Gaia J0611+6931 Flamingos-2 JH, HK grism
Spectroscopy
f723.dat 17 3271 Gaia J0723+6301 GNIRS 0.8-2.5um Spectroscopy
f2100.dat 17 4628 Gaia J2100+2122 MOSFIRE J, H, K band Spectroscopy
fwd.dat 17 4668 WD0145+234 MOSFIRE J, H, K band Spectroscopy
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See also:
I/354 : StarHorse2, Gaia EDR3 photo-astrometric distances (Anders+, 2022)
J/AJ/131/2722 : New L and T dwarfs from the SDSS (Chiu+, 2006)
J/ApJ/663/1291 : DZ stars in SDSS DR4 (Dufour+, 2007)
J/ApJS/197/38 : The WIRED survey. II. (Debes+, 2011)
J/MNRAS/417/1210 : DA-white dwarfs from SDSS and UKIDSS (Girven+, 2011)
J/MNRAS/449/574 : Circumstellar discs at white dwarfs (Rocchetto+, 2015)
J/ApJ/898/84 : Spectro follow-up of 100pc WDs in SDSS & Gaia (Kilic+, 2020)
J/ApJ/902/127 : Bright Gaia white dwarfs with unWISE photometry (Xu+, 2020)
J/MNRAS/508/3877 : Catalogue of white dwarfs in Gaia EDR3 (Gentile+, 2021)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- Name White dwarf identifier
17- 26 F10.6 deg RAdeg [1/316] Degree of right ascension (J2000)
28- 37 F10.6 deg DEdeg [-70/64] Degree of declination (J2000)
39- 44 F6.2 pc Dist [29.4/152] Distance
46- 49 F4.2 pc e_Dist [0.02/2] Error on Dist
51- 53 A3 --- SpT Spectral type; DA or DAZ
55- 59 I5 K Teff [7749/25565] Effective temperature
61- 64 I4 K e_Teff [77/1000] Error on Teff
66- 69 F4.2 cm/s2 logg [7.92/8.14] Surface gravity
71- 74 F4.2 cm/s2 e_logg [0.01/0.1] Error on logg
76 A1 --- l_[Ca/H] [<] Limit sign of [Ca/H]
78- 82 F5.2 --- [Ca/H] [-8.8/-6.03] Ca/H ratio log
84- 87 F4.2 --- e_[Ca/H] [0.1/0.2]? Error on [Ca/H]
89 A1 --- f_[Ca/H] An a flag means new analysis from this paper
91 A1 --- l_MCa [<] Limit flag on MCa
93- 97 E5.2 g/s MCa [16000/8.2e+06] Ca rate of flow
99-180 A82 --- Ref Reference used
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Byte-by-byte Description of file: f*.dat
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Bytes Format Units Label Explanations
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1- 7 F7.5 um wave Wavelength axis
9- 17 F9.7 Jy flux ? Flux axis
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 26-Jan-2024