J/ApJ/878/63 Cool WD atmosphere models. IV. Spectral evolution (Blouin+, 2019)
A new generation of cool white dwarf atmosphere models.
IV. Revisiting the spectral evolution of cool white dwarfs.
Blouin S., Dufour P., Thibeault C., Allard N.F.
<Astrophys. J., 878, 63 (2019)>
=2019ApJ...878...63B 2019ApJ...878...63B
ADC_Keywords: Stars, white dwarf; Models, atmosphere; Photometry, ugriz;
Parallaxes, trigonometric; Stars, masses; Abundances
Keywords: opacity ; stars: atmospheres ; stars: evolution ; white dwarfs
Abstract:
As a result of competing physical mechanisms, the atmospheric
composition of white dwarfs changes throughout their evolution, a
process known as spectral evolution. Because of the ambiguity of their
atmospheric compositions and the difficulties inherent to the modeling
of their dense atmospheres, no consensus exists regarding the spectral
evolution of cool white dwarfs (Teff<6000K). In the previous papers of
this series, we presented and observationally validated a new
generation of cool white dwarf atmosphere models that include all the
necessary constitutive physics to accurately model those objects.
Using these new models and a homogeneous sample of 501 cool white
dwarfs, we revisit the spectral evolution of cool white dwarfs. Our
sample includes all spectroscopically identified white dwarfs cooler
than 8300K for which a parallax is available in Gaia DR2 and
photometric observations are available in Pan-STARRS1 and 2MASS.
Except for a few cool carbon-polluted objects, our models allow an
excellent fit to the spectroscopic and photometric observations of all
objects included in our sample. We identify a decrease of the ratio of
hydrogen- to helium-rich objects between 7500 and 6250K, which we
interpret as the signature of convective mixing. After this decrease,
hydrogen-rich objects become more abundant up to 5000K. This puzzling
increase, reminiscent of the non-DA gap, has yet to be explained. At
lower temperatures, below 5000K, hydrogen-rich white dwarfs become
rarer, which rules out the scenario in which the accretion of hydrogen
from the interstellar medium dominates the spectral evolution of cool
white dwarfs.
Description:
We relied on the Montreal White Dwarf Database (MWDD;
Dufour+ 2017ASPC..509....3D 2017ASPC..509....3D) to identify objects that match our
selection criteria. In short, parallax measurement available in
Gaia DR2 (I/345), grizy photometry available from PS1 (II/349), J-band
photometry (at least) from 2MASS (II/246), spectrum available,
unresolved binary systems rejected, and objects cooler than 8300K were
retained. See section 2.1 for details.
Our model atmosphere code is described at length in Paper I
(Blouin+ 2018ApJ...863..184B 2018ApJ...863..184B).
Following the fitting procedures described in Section 2.3, we obtained
the atmospheric parameters of all 501 objects included in our sample.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 110 501 Astrometry of objects included in our sample
table2.dat 75 501 Spectral type and photometric data
table3.dat 76 501 Atmospheric parameters
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See also:
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
II/349 : The Pan-STARRS release 1 (PS1) Survey - DR1 (Chambers+, 2016)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/ApJS/133/413 : BVRIJHK photometry of cool white dwarfs (Bergeron+, 2001)
J/AJ/126/1023 : White Dwarfs in the SDSS (Harris+, 2003)
J/ApJS/156/47 : DA white dwarfs from the Palomar Green Survey (Liebert+, 2005)
J/AJ/131/582 : Cool white dwarfs in the SDSS (Kilic+, 2006)
J/ApJ/643/402 : Cool white dwarfs in the solar neighborhood (Kawka+, 2006)
J/AJ/132/676 : SDSS hot DB white dwarfs (Eisenstein+, 2006)
J/ApJS/167/40 : SDSS4 confirmed white dwarfs catalog (Eisenstein+, 2006)
J/AJ/134/252 : New nearby white dwarf systems (Subasavage+, 2007)
J/ApJ/663/1291 : DZ stars in SDSS DR4 (Dufour+, 2007)
J/ApJS/190/77 : Detailed analysis of cool WDs in the SDSS (Kilic+, 2010)
J/MNRAS/413/1121 : SDSS post-common env. binaries. X (Rebassa-Mansergas+ 2011)
J/ApJ/743/138 : Spectroscopic survey of bright white dwarfs (Gianninas+, 2011)
J/AJ/143/103 : New white dwarfs (Sayres+, 2012)
J/MNRAS/425/1394 : High proper-motion white dwarfs (Kawka+, 2012)
J/ApJS/204/5 : SDSS DR7 white dwarf catalog (Kleinman+, 2013)
J/AJ/145/136 : Astrometry & photometry of nearby WDs (Limoges+, 2013)
J/A+A/566/L8 : He IR absorption profiles (Kowalski, 2014)
J/A+A/571/A47 : Extensive linelist of CH in stellar atm. (Masseron+, 2014)
J/ApJS/215/21 : Hydrogen and Helium EOS in brown dwarfs (Becker+, 2014)
J/MNRAS/446/4078 : New white dwarf stars in SDSS DR10 (Kepler+, 2015)
J/MNRAS/449/3966 : Ultracool white dwarfs (Gianninas+, 2015)
J/ApJS/219/19 : Census of nearby white dwarfs from SUPERBLINK (Limoges+, 2015)
J/MNRAS/455/3413 : New WD & subdwarf stars in SDSS DR12 (Kepler+, 2016)
J/MNRAS/467/4970 : Cool DZ white dwarfs. I. (Hollands+, 2017)
J/AJ/154/32 : Solar neighborhood. XXXIX. Nearby WDs (Subasavage+, 2017)
J/A+A/619/A152 : MgHe line profile variations with temperature (Allard+, 2018)
http://montrealwhitedwarfdatabase.org/ : MWDD home page
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 22 A22 --- PSO Pan-STARRS object name (JHHMMSS.sss+DDMMSS.sss)
24- 52 A29 --- OName Montreal White Dwarf Database (MWDD) object ID
54- 72 I19 --- Gaia Gaia DR2 object ID (1)
74- 84 F11.7 deg RAdeg [0.6/359] Gaia Right Ascension (ICRS) at Ep=2015.5
86- 96 F11.7 deg DEdeg [-30.6/85.05] Gaia Declination (ICRS) at Ep=2015.5
98-104 F7.3 mas plx [7.78/155.3]? Gaia parallax
106-110 F5.3 mas e_plx [0.016/0.81]? Error on plx
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Note (1): Three Gaia DR2 IDs and associated data have been corrected by CDS;
i.e. data for EGGR 462, WD 1630+089 and WD 1120+073.
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Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
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1- 22 A22 --- PSO Pan-STARRS object name (JHHMMSS.sss+DDMMSS.sss)
24- 27 A4 --- SpT Spectral Type
29- 33 F5.2 mag gmag [13.85/19.24] PAN-STARRS apparent g (AB) magnitude
35- 39 F5.2 mag rmag [13.62/18.47] PAN-STARRS apparent r (AB) magnitude
41- 45 F5.2 mag imag [13.58/18.15] PAN-STARRS apparent i (AB) magnitude
47- 51 F5.2 mag zmag [13.66/18.02] PAN-STARRS apparent z (AB) magnitude
53- 57 F5.2 mag ymag [13.67/18.03] PAN-STARRS apparent y (AB) magnitude
59- 63 F5.2 mag Jmag [13.01/17.04] 2MASS apparent J magnitude
65- 69 F5.2 mag Hmag [12.86/16.83]? 2MASS apparent H magnitude
71- 75 F5.2 mag Ksmag [12.76/16.17]? 2MASS apparent Ks magnitude
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 22 A22 --- PSO Pan-STARRS object name (JHHMMSS.sss+DDMMSS.sss)
24- 27 I4 K Teff [3835/8300] Effective temperature
29- 31 I3 K e_Teff [20/290] Error in Teff
33- 37 F5.3 [cm/s2] logg [6.44/8.88] Log of surface gravity
39- 43 F5.3 [cm/s2] e_logg [0.008/0.14] Error in logg
45- 49 F5.3 Msun Mass [0.03/1.14] Mass
51- 55 F5.3 Msun e_Mass [0.003/0.09] Error in mass
57- 60 F4.2 Gyr cAge [0.3/9.1] White dwarf cooling age
62- 65 A4 --- H-He Log H/He
67- 70 F4.1 [-] [C/He] [-8.4/-5.2]? Log of the C/He ratio
72- 76 F5.1 [-] [Ca/He] [-11.7/-8.1]? Log of the Ca/He ratio
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History:
From electronic version of the journal
* Misprint on declination signs replaced in column PSO in Tables 1-3.
Note that in Table 1, Gaia DR2 3817534337625985280 is not the WD,
it should be Gaia DR2 3817534337626005632.
References:
Blouin et al. Paper I. 2018ApJ...863..184B 2018ApJ...863..184B
Blouin et al. Paper II. 2018ApJ...867..161B 2018ApJ...867..161B
Blouin et al. Paper III. 2019ApJ...872..188B 2019ApJ...872..188B
Blouin et al. Paper IV. 2019ApJ...878...63B 2019ApJ...878...63B This catalog
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 03-Dec-2020