J/MNRAS/467/4970 Cool DZ white dwarfs. I. (Hollands+, 2017)
Cool DZ white dwarfs. I. Identification and spectral analysis.
Hollands M.A., Koester D., Alekseev V., Herbert E.L., Gansicke B.T.
<Mon. Not. R. Astron. Soc., 467, 4970-5000 (2017)>
=2017MNRAS.467.4970H 2017MNRAS.467.4970H (SIMBAD/NED BibCode)
ADC_Keywords: Stars, white dwarf ; Photometry, SDSS ; Abundances
Keywords: planets and satellites: composition - stars: abundances -
stars: atmospheres - white dwarfs
Abstract:
White dwarfs with metal lines in their spectra act as signposts for
post-main-sequence planetary systems. Searching the Sloan Digital Sky
Survey (SDSS) Data Release 12, we have identified 231 cool (<9000K)
DZ white dwarfs with strong metal absorption, extending the DZ cooling
sequence to both higher metal abundances and lower temperatures, and
hence longer cooling ages. Of these 231 systems, 104 are previously
unknown white dwarfs. Compared with previous work, our spectral
fitting uses improved model atmospheres with updated line profiles and
line-lists, which we use to derive effective temperatures and
abundances for up to eight elements. We also determine spectroscopic
distances to our sample, identifying two halo members with tangential
space velocities >300km/s. The implications of our results on
remnant planetary systems are to be discussed in a separate paper.
Description:
The catalogue contains parameters for a sample of 231 cool DZ white
dwarfs, identified in the Sloan Digital Sky Survey (SDSS) Data Release
12, and showing strong photospheric absorption features in their
spectra.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 112 231 SDSS PSF photometry for all white dwarfs
in our sample
table6.dat 74 230 Derived parameters from atmospheric modelling of
the SDSS and WHT spectra
table7.dat 50 230 The mass fraction of the convection zone, q, and
logarithm of the diffusion time-scale in years
for each element
table8.dat 62 230 Distances, proper motions, transverse motions
and white dwarf cooling ages for our DZ sample
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See also:
V/147 : The SDSS Photometric Catalogue, Release 12 (Alam+, 2015)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 18 A18 --- SDSS SDSS name (HHMMSS.ss+DDMMSS.s)
20- 33 A14 --- PMF SDSS Plate-MJD-Fiber
35 I1 --- Nsdss Number of SDSS spectra available per object
37- 42 F6.3 mag umag SDSS u magnitude
44- 48 F5.3 mag e_umag rms uncertainty on umag
50- 55 F6.3 mag gmag SDSS g magnitude
57- 61 F5.3 mag e_gmag rms uncertainty on gmag
63- 68 F6.3 mag rmag SDSS r magnitude
70- 74 F5.3 mag e_rmag rms uncertainty on rmag
76- 81 F6.3 mag imag SDSS i magnitude
83- 87 F5.3 mag e_imag rms uncertainty on imag
89- 94 F6.3 mag zmag SDSS z magnitude
96-100 F5.3 mag e_zmag rms uncertainty on zmag
102 A1 --- Note [*] * for the source not in other tables
104-112 A9 --- SName SDSS short name (HHMM+DDMM)
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- SName SDSS short name (HHMM+DDMM)
11- 14 I4 K Teff Effective temperature
16- 18 I3 K e_Teff rms uncertainty on Teff
20- 25 F6.2 [-] [Ca/He] Abundance [Ca/He]
27- 32 F6.2 [-] [Mg/He] Abundance [Mg/He]
34- 39 F6.2 [-] [Fe/He] Abundance [Fe/He]
41- 46 F6.2 [-] [Na/He] ? Abundance [Na/He]
48- 53 F6.2 [-] [Cr/He] ? Abundance [Cr/He]
55- 60 F6.2 [-] [Ti/He] ? Abundance [Ti/He]
62- 67 F6.2 [-] [Ni/He] ? Abundance [Ni/He]
69- 70 A2 --- l_[H/He] [≤ ] Limit flag on [H/He]
71- 74 F4.1 [-] [H/He] ? Abundance [H/He]
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Byte-by-byte Description of file: table7.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- SName SDSS short name (HHMM+DDMM)
11- 15 F5.2 [-] logq Mass fraction of the convection zone
17- 20 F4.2 [yr] tCa logarithm of the diffusion time-scale for Ca
22- 25 F4.2 [yr] tMg logarithm of the diffusion time-scale for Mg
27- 30 F4.2 [yr] tFe logarithm of the diffusion time-scale for Fe
32- 35 F4.2 [yr] tNa logarithm of the diffusion time-scale for Na
37- 40 F4.2 [yr] tCr logarithm of the diffusion time-scale for Cr
42- 45 F4.2 [yr] tTi logarithm of the diffusion time-scale for Ti
47- 50 F4.2 [yr] tNi logarithm of the diffusion time-scale for Ni
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Byte-by-byte Description of file: table8.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- SName SDSS short name (HHMM+DDMM)
12- 16 F5.1 pc Dist Distance
18- 21 F4.1 pc e_Dist rms uncertainty on Dist
23- 27 F5.1 mas/yr pm ? Total proper motion
30- 33 F4.1 mas/yr e_pm ? rms uncertainty on pm
35- 39 F5.1 km/s vperp ? Perpendicular velocity
45- 48 F4.1 km/s e_vperp ? rms uncertainty on vperp
50- 52 F3.1 Gyr tau Age
55- 57 F3.1 Gyr E_tau Error on tau (upper value)
60- 62 F3.1 Gyr e_tau Error on tau (lower value)
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 29-Nov-2019