J/A+A/546/L3 Spectrum of LSR J0745+2627 (Catalan+, 2012)
The brightest pure-H ultracool white dwarf.
Catalan S., Tremblay P.-E., Pinfield D.J., Smith L.C., Zhang Z.H.,
Napiwotzki R., Marocco F., Day-Jones A.C., Gomes J., Forde K.P.,
Lucas P. W., Jones H.R.A.
<Astron. Astrophys. 546, L3 (2012)>
=2012A&A...546L...3C 2012A&A...546L...3C
ADC_Keywords: Stars, white dwarf ; Spectra, infrared
Keywords: stars: white dwarfs - stars: Population II - stars: abundances -
stars: individual (ULAS J074509.02+262705.0) -
stars: individual (SDSS J074509.02+262705.0) -
stars: fundamental parameters
Abstract:
We report the identification of LSR J0745+2627 in the United Kingdom
InfraRed Telescope Infrared Deep Sky Survey (UKIDSS) Large Area Survey
(LAS) as a cool white dwarf with kinematics and age compatible with
the thick-disk/halo population. LSR J0745+2627 has a high proper
motion (890mas/yr) and a high reduced proper motion value in the J
band (H_J=21.87). We show how the infrared-reduced proper motion
diagram is useful for selecting a sample of cool white dwarfs with low
contamination. LSR J0745+2627 is also detected in the Sloan Digital
Sky Survey (SDSS) and the Wide-field Infrared Survey Explorer (WISE).
We have spectroscopically confirmed this object as a cool white dwarf
using X-Shooter on the Very Large Telescope. An analysis of its
spectral energy distribution reveals that its atmosphere is compatible
with a pure-H composition model with an effective temperature of
3880±90K. This object is the brightest pure-H ultracool white dwarf
(Teff<4000K) ever identified. We have constrained the distance
(24-45pc), space velocities and age considering different surface
gravities. The results obtained suggest that LSR J0745+2627 belongs to
the thick-disk/halo population and is also one of the closest
ultracool white dwarfs.
Description:
Spectrum of LSR J0745+2627 obtained using XShooter at VLT, Paranal
Observatory. No smoothing has been applied to this spectrum.
Objects:
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RA (2000) DE Designation(s)
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07 45 08.94 +26 27 06.6 LSR J0745+2627 = LSPM J0745+2627
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table.dat 33 13538 Spectrum of LSR J0745+2627
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Byte-by-byte Description of file: table.dat
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Bytes Format Units Label Explanations
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1- 7 F7.1 0.1nm lambda [3098/24759] Wavelength
9- 20 E12.5 cW/m2/nm Flux Flux (in erg/cm2/s/Å)
23- 33 E11.5 cW/m2/nm e_Flux Flux error
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Acknowledgements:
Silvia Catalan, s.catalan(at)herts.ac.uk
(End) Silvia Catalan [Univ. Hertfordshire], Patricia Vannier [CDS] 12-Sep-2012