J/ApJ/871/13 Asteroseismology of the WD GD358, 1982-2016 (Bischoff-Kim+, 2019)
GD358: three decades of observations for the in-depth asteroseismology of a
DBV star.
Bischoff-Kim A., Provencal J.L., Bradley P.A., Montgomery M.H.,
Shipman H.L., Harrold S.T., Howard B., Strickland W., Chandler D.,
Campbell D., Arredondo A., Linn R., Russell D.P., Doyle D., Brickhouse A.,
Peters D., Kim S.-L., Jiang X.J., Mao Y.-N., Kusakin A.V., Sergeev A.V.,
Andreev M., Velichko S., Janulis R., Pakstiene E., Alicavus F., Horoz N.,
Zola S., Ogloza W., Koziel-Wierzbowska D., Kundera T., Jableka D.,
Debski B., Baran A., Meingast S., Nagel T., Loebling L., Heinitz C.,
Hoyer D., Bognar Z., Castanheira B.G., Erdem A.
<Astrophys. J., 871, 13 (2019)>
=2019ApJ...871...13B 2019ApJ...871...13B
ADC_Keywords: Asteroseismology; Photometry, CCD; Stars, white dwarf
Keywords: stars: oscillations (including pulsations) ;
stars: variables: general ; white dwarfs
Abstract:
We report on the analysis of 34 years of photometric observations of
the pulsating helium atmosphere white dwarf GD358. The complete data
set includes archival data from 1982 to 2006, and 1195.2hr of new
observations from 2007 to 2016. From this data set, we extract 15
frequencies representing g-mode pulsation modes, adding 4 modes to the
11 modes known previously. We present evidence that these 15 modes are
l=1 modes, 13 of which belong to a consecutive sequence in radial
overtone k. We perform a detailed asteroseismic analysis using models
that include parameterized, complex, carbon and oxygen core
composition profiles to fit the periods. Recent spectroscopic analyses
place GD358 near the red edge of the DBV instability strip, at
24000±500K and a logg of 7.8±0.08dex. The surface gravity
translates to a mass range of 0.455-0.540M☉. Our best-fit model
has a temperature of 23650K and a mass of 0.5706M☉. That is
slightly more massive than what is suggested by the most recent
spectroscopy. We find a pure helium layer mass of 10-5.50,
consistent with the result of previous studies and the outward
diffusion of helium over time.
Description:
We analyzed archival data and 1195.2hr of new observations for the
white dwarf (WD) pulsator GD358, together covering a span of 34yr.
GD358 was discovered in 1982 (Winget+ 1982ApJ...252L..65W 1982ApJ...252L..65W) and
was a target of the Whole Earth Telescope (WET) in 1990, 1994, 2000,
and 2006 (Winget+ 1994ApJ...430..839W 1994ApJ...430..839W ; Kepler+ 2003A&A...401..639K 2003A&A...401..639K
and Provencal+ 2009ApJ...693..564P 2009ApJ...693..564P).
New observations presented here include individual observing runs
spanning 2007-2016. Each season of observations was obtained as part
of multi-site WET campaigns.
Objects:
----------------------------------------------------------
RA (ICRS) DE Designation(s)
----------------------------------------------------------
16 47 18.39 +32 28 32.9 GD358 = WD 1645+32
----------------------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 49 286 Journal of observations
table2.dat 45 213 1982-2006 detected independent frequencies
table3.dat 48 171 2007-2016 detected independent frequencies
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See also:
B/wd : Spectroscopically identified white dwarfs (McCook+, 2014)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/A+A/317/689 : Hot subdwarfs proper motions (Thejll+ 1997)
J/A+A/363/1040 : DB WDs from the Hamburg/ESO survey (Friedrich+, 2000)
J/ApJ/631/1100 : Atmospheric parameters of DA white dwarfs (Gianninas+, 2005)
J/ApJS/161/394 : Low-luminosity companions to white dwarfs (Farihi+, 2005)
J/AJ/132/676 : SDSS hot DB white dwarfs (Eisenstein+, 2006)
J/MNRAS/399/699 : Parameters of atmopsheres of white dwarfs (Mortlock+, 2009)
J/A+A/548/A79 : INTEGRAL-OMC opt. variable sources (Alfonso-Garzon+, 2012)
J/A+A/557/A19 : Mass & age of extreme low-mass white dwarfs (Althaus+, 2013)
J/ApJ/794/35 : Binary white dwarfs atmospheric param. (Gianninas+, 2014)
J/MNRAS/454/2787 : LAMOST DR2 white dwarfs (Guo+, 2015)
J/A+A/583/A86 : DB white dwarfs in SDSS DR10 and DR12 (Koester+, 2015)
J/A+A/595/A35 : Low-mass He white dwarfs evolutionary models (Istrate+,2016)
J/ApJ/835/173 : Kepler asteroseismic LEGACY sample II. (Silva Aguirre+, 2017)
J/ApJ/848/11 : Spectroscopic & photometric analysis of WDs (Bedard+, 2017)
J/ApJS/232/23 : 27 pulsating DA WDs follow-up observations (Hermes+, 2017)
J/MNRAS/472/4173 : Bright WDs for high-speed photometry (Raddi+, 2017)
J/A+A/618/A113 : Spectropolarimetric survey of white dwarfs (Bagnulo+, 2018)
J/ApJS/241/32 : OB stars from the LAMOST DR5 spectra (Liu+, 2019)
http://www.physics.udel.edu/gp/darc/wet : Whole Earth Telescope (WET) home page
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 13 A13 --- ObsID Observation's run name (1)
15- 28 A14 --- Tel Telescope identifier (2)
30- 33 A4 --- Inst Detector used
35- 38 I4 yr Obs.Y [2007/2016] Year of the observation
40- 41 I2 "month" Obs.M [4/8] Month of the observation
43- 44 I2 d Obs.D Day of the observation
47- 49 F3.1 h Exp [0.4/8.9] Length of observation
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Note (1): Data from the Warwick 1.0m telescope was obtained during
an engineering run.
Note (2): Telescope as follows:
BOAO 1.8 = The 1.8m telescope of Bohyunsan Optical Astronomy Observatory
(BOAO) in Korea (3 occurrences)
Canakkale 1.2 = The T-122 telescope at the Canakkale University Observatory,
Turkey (15 occurrences)
Hvar 1.0 = 1m telescope of the Hvar Observatory, Croatia (8 occurrences)
Krakow 0.4 = 0.4m telescope, Krakow (42 occurrences)
MCAO 0.6 = The 24 inch (0.6m) Tinsley telescope of Mount Cuba
Astronomical Observatory, Wilmington, USA (29 occurrences)
McDonald 2.1 = The 2.1 m(82") Otto Struve Telescope of the McDonald
Observatory, Texas, USA (1 occurrences)
Moletai 1.65 = The 1.65m telescope of Moletai Observatory, Lithuania
(16 occurrences)
Mt. Lemmon 1.0 = The 1.0-meter reflector located on Mt. Lemmon, owned by the
Steward Observatory of the University of Arizona
(11 occurrences)
NAOC 0.5 = The 50-cm telescope of the Xinglong Observatory of the
National Astronomical Observatories, Chinese Academy of
Sciences (NAOC) (7 occurrences)
NAOC 0.85 = The NAOC (National Astronomical Observatories
of China)-Beijing Normal University Telescope (NBT) 0.85m
telescope (9 occurrences)
PJMO 0.6 = The 0.6m telescope of the Paul and Jane Meyer Observatory of
the Central Texas Astronomical Society (48 occurrences)
PROMPT 0.4 = The PROMPT (Panchromatic Robotic Optical Monitoring and
Polarimetry Telescopes) 0.4m telescope located at Cerro
Tololo Inter-American Observatory (16 occurrences)
Suhora 0.6 = The 0.6m Cassegrain telescope of the Mount Suhora Observatory,
in Krakow, Poland (24 occurrences)
Terskol 0.6 = The Zeiss-600 telescope at Peak Terskol Observatory, Russia
(2 occurrences)
Terskol 2.0 = The 2m RCC telescope at Peak Terskol Observatory, Russia
(10 occurrences)
Tien Shan 1.0 = The Tien Shan Astronomical Observatory 1m telescope,
Kazakhstan (10 occurrences)
Tubitak 1.0 = The 1m fully automatic T100 telescope of the Tubitak National
Observatory (Turkey) (6 occurrences)
Tuebingen 0.8 = The Tubingen 80-cm reflector of the Institute for Astronomy
and Astrophysics (IAAT) of Tubingen, Germany (25 occurrences)
Vienna 0.6 = The Vienna observatory 0.6m telescope, Austria (1 occurrences)
Warwick 1.0m = The Warwick 1m telescope (3 occurrences)
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 4 I4 yr Obs.Y [1982/2006] Year of the observation
6- 13 F8.3 uHz Freq [923/2379] Frequency
15- 19 F5.3 uHz e_Freq [0.001/3.5] Uncertainty in Freq
21- 27 F7.2 s Per [420/1083] Period
29- 33 F5.2 mmag Amp [1/36] Amplitude
35- 39 F5.3 mmag e_Amp [0.01/1.1] Uncertainty in Amp
41- 45 F5.1 --- S/N [2.4/119] Signal-to-noise ratio
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 4 I4 yr Obs.Y [2007/2016] Year of the observation
6- 13 F8.3 uHz Freq [954/2373] Frequency
15- 19 F5.3 uHz e_Freq [0.001/0.09]? Uncertainty in Freq
21- 28 F8.3 s Per [421/1048] Period
30- 35 F6.3 mmag Amp [1.1/30] Amplitude
37- 41 F5.3 mmag e_Amp [0.01/0.8] Uncertainty in Amp
43- 48 F6.2 --- S/N [2.4/151] Signal-to-Noise ratio
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie FIX [CDS] 13-Feb-2020