J/ApJS/232/23 27 pulsating DA WDs follow-up observations (Hermes+, 2017)
White dwarf rotation as a function of mass and a dichotomy of mode line widths:
Kepler observations of 27 pulsating DA white dwarfs through K2 Campaign 8.
Hermes J.J., Gansicke B.T., Kawaler S.D., Greiss S., Tremblay P.-E.,
Gentile Fusillo N.P., Raddi R., Fanale S.M., Bell K.J., Dennihy E.,
Fuchs J.T., Dunlap B.H., Clemens J.C., Montgomery M.H., Winget D.E.,
Chote P., Marsh T.R., Redfield S.
<Astrophys. J. Suppl. Ser., 232, 23 (2017)>
=2017ApJS..232...23H 2017ApJS..232...23H
ADC_Keywords: Stars, white dwarf ; Photometry, SDSS ; Spectroscopy ;
Stars, masses
Keywords: stars: oscillations ; stars: variables: general ; white dwarfs
Abstract:
We present photometry and spectroscopy for 27 pulsating
hydrogen-atmosphere white dwarfs (DAVs; a.k.a. ZZ Ceti stars) observed
by the Kepler space telescope up to K2 Campaign 8, an extensive
compilation of observations with unprecedented duration (>75 days) and
duty cycle (>90%). The space-based photometry reveals pulsation
properties previously inaccessible to ground- based observations. We
observe a sharp dichotomy in oscillation mode line widths at roughly
800s, such that white dwarf pulsations with periods exceeding 800s
have substantially broader mode line widths, more reminiscent of a
damped harmonic oscillator than a heat-driven pulsator. Extended
Kepler coverage also permits extensive mode identification: we
identify the spherical degree of 87 out of 201 unique radial orders,
providing direct constraints of the rotation period for 20 of these 27
DAVs, more than doubling the number of white dwarfs with rotation
periods determined via asteroseismology. We also obtain spectroscopy
from 4m-class telescopes for all DAVs with Kepler photometry. Using
these homogeneously analyzed spectra, we estimate the overall mass of
all 27 DAVs, which allows us to measure white dwarf rotation as a
function of mass, constraining the endpoints of angular momentum in
low- and intermediate-mass stars. We find that 0.51-0.73M☉ white
dwarfs, which evolved from 1.7-3.0M☉ ZAMS progenitors, have a mean
rotation period of 35hr with a standard deviation of 28hr, with
notable exceptions for higher-mass white dwarfs.
Description:
All observations analyzed here were collected by the Kepler spacecraft
with short-cadence exposures from 2012 to 2016. Full details of the
raw and processed Kepler and K2 observations are summarized in Table2.
We complemented our space-based photometry of these 27 pulsating
hydrogen-atmosphere white dwarfs (DAVs) by determining their
atmospheric parameters based on model-atmosphere fits to follow-up
spectroscopy obtained from two 4m class, ground-based facilities.
Spectra taken with the 4.2m William Herschel Telescope (WHT) on the
island of La Palma cover roughly 3800-5100Å at roughly 2.0Å
resolution; spanning 2013 Jun 06 to 2014 Jul 25. Spectra taken with
the 4.1m Southern Astrophysical Research (SOAR) telescope on Cerro
Pachon in Chile cover roughly 3600-5200Å; spanning 2014 Oct 13 to
2017 Apr 21. We detail these spectroscopic observations and their
resultant fits in Table 3.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 102 27 Target selection criterion for the first 27
pulsating DA white dwarfs observed by Kepler and K2
table2.dat 88 27 Details of short-cadence photometry of the first
27 pulsating DA white dwarfs observed by Kepler
and K2
table3.dat 94 27 Follow-up spectroscopy of the first 27 pulsating
DA white dwarfs observed by Kepler and K2
table5.dat 143 389 Pulsation information from linear least-squares
(LLS; Section 3) and Lorentzian (Lor.; Section 5)
fits for the first 27 DAVs observed by Kepler and K2
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See also:
V/133 : Kepler Input Catalog (Kepler Mission Team, 2009)
V/147 : The SDSS Photometric Catalogue, Release 12 (Alam+, 2015)
II/350 : VLT Survey Telescope ATLAS (Shanks+, 2015)
II/336 : AAVSO Photometric All Sky Survey (APASS) DR9 (Henden+, 2016)
IV/34 : K2 Ecliptic Plane Input Catalog (EPIC) (Huber+, 2017)
J/ApJS/156/47 : DA WDs from the Palomar Green Survey (Liebert+, 2005)
J/MNRAS/409/1470 : Kepler compact pulsator candidates (Ostensen+, 2010)
J/AJ/142/112 : KIC photometric calibration (Brown+, 2011)
J/ApJ/743/138 : Spectroscopic survey of bright WDs (Gianninas+, 2011)
J/ApJ/730/128 : Spectroscopy of DA WD from the SDSS-DR4 (Tremblay+, 2011)
J/MNRAS/417/1210 : DA-white dwarfs from SDSS and UKIDSS (Girven+, 2011)
J/AJ/144/24 : The Kepler-INT survey (KIS) (Greiss+, 2012)
J/ApJS/204/5 : SDSS DR7 white dwarf catalog (Kleinman+, 2013)
J/MNRAS/448/2260 : White dwarf candidates in SDSS DR10 (Gentile Fusillo+, 2015)
J/MNRAS/461/4059 : The pulsations of G 207-9 and LP 133-144 (Bognar+, 2016)
J/MNRAS/458/3808 : DR9-12 SDSS WDMS binaries (Rebassa-Mansergas+, 2016)
J/MNRAS/469/621 : VST ATLAS WD candidates cat. (Gentile Fusillo+, 2017)
J/ApJ/835/172 : Kepler asteroseismic LEGACY sample. I. Oscillations (Lund+,
2017)
http://k2wd.org/ : Kepler and K2 obs. of white dwarf stars home page
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 I9 --- ID The KIC/EPIC identifier
11- 12 I2 h RAh Hour of Right Ascension (J2000)
14- 15 I2 min RAm Minute of Right Ascension (J2000)
17- 22 F6.3 s RAs Second of Right Ascension (J2000)
24 A1 --- DE- Sign of the Declination (J2000)
25- 26 I2 deg DEd Degree of Declination (J2000)
28- 29 I2 arcmin DEm Arcminute of Declination (J2000)
31- 35 F5.2 arcsec DEs Arcsecond of Declination (J2000)
37- 47 A11 --- AName Alternate identifier
49- 52 F4.1 mag gmag [13/19] The g band apparent magnitude (1)
54- 57 F4.2 mag u-g [0.3/0.7]? The (u-g) AB color index
59- 63 F5.2 mag g-r [-0.3/-0.01]? The (g-r) AB color index
65- 68 F4.2 mag B-R [0.02/0.1]? The (B-R) AB color index
70- 73 F4.2 mag R-I [0.03]? The (R-I) AB color index
75- 79 A5 --- Cat Source catalog (2)
81- 83 A3 --- K2 K2 field
85- 89 A5 --- Prop GO proposal identifier
91-100 A10 --- Sel Selection method
102 I1 --- Ref ? Discovery announcement code (3)
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Note (1): From any of the SDSS, VST/ATLAS, APASS, or Kepler-INT Survey (KIS)
photometric surveys.
Note (2): Catalog as follows:
SDSS = White dwarf candidates in SDSS DR10
(Gentile Fusillo+, 2015, J/MNRAS/448/2260)
KIS = Kepler-INT Survey (Greiss et al. 2012, J/AJ/144/24)
SSS = Supercosmos Sky Survey (SSS) catalog of
Rowell & Hambly (2011MNRAS.417...93R 2011MNRAS.417...93R)
ATLAS = VLT Survey Telescope ATLAS (Shanks+, 2015, II/350)
Note (3): Reference as follows:
1 = Greiss et al. (2016MNRAS.457.2855G 2016MNRAS.457.2855G);
2 = Hermes et al. (2011ApJ...741L..16H 2011ApJ...741L..16H);
3 = Greiss et al. (2014MNRAS.438.3086G 2014MNRAS.438.3086G);
4 = Gianninas et al. (2006AJ....132..831G 2006AJ....132..831G);
5 = Castanheira et al. (2010MNRAS.405.2561C 2010MNRAS.405.2561C);
6 = Mukadam et al. (2004ApJ...607..982M 2004ApJ...607..982M);
7 = Pyrzas et al. (2015MNRAS.447..691P 2015MNRAS.447..691P) - search for DAVs in WD+dM systems;
8 = Voss et al. (2006A&A...450.1061V 2006A&A...450.1061V);
9 = Hermes et al. (2017ApJ...841L...2H 2017ApJ...841L...2H).
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 I9 --- ID The KIC/EPIC identifier
11- 13 A3 --- K2 K2 Field identifier
15- 18 F4.1 mag Kpmag [13/19] Kepler magnitude
20- 21 I2 --- Rel [8/25]?=-1 Data release identifier
23- 24 I2 --- CCD CCD channel
26- 27 I2 pix Ap [1/93] Final fixed aperature size
29- 32 F4.2 --- TFrac Total fraction of flux contained in aperture
that belongs to the target.
34- 44 F11.6 d T0 Observation date (BJDTDB-2454833.0)
46- 50 F5.2 d Dur [8.9/98] Duration
52- 55 F4.1 % DC Duty cycle
57- 61 F5.3 uHz Res [0.05/0.7] Resolution
63- 67 F5.3 --- 1FAP The 1% False Alarm Probability (4)
69- 73 F5.3 --- 0.1FAP The 0.1% False Alarm Probability (4)
75- 79 F5.3 --- <5A> [0.1/2.7] Five times average amplitude (5)
81- 86 F6.1 s WMP [141/1205] Weighted mean period
88 I1 --- Ref2 ? Publication code (6)
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Note (4): In units of parts per thousand.
Note (5): Of entire Fourier transform in units of parts per thousand.
Note (6): Reference as follows:
1 = Bell et al. (2015ApJ...809...14B 2015ApJ...809...14B);
2 = Greiss et al. (2014MNRAS.438.3086G 2014MNRAS.438.3086G);
3 = Hermes et al. (2014ApJ...789...85H 2014ApJ...789...85H);
4 = Hermes et al. (2015MNRAS.451.1701H 2015MNRAS.451.1701H);
5 = Hermes et al. (2017ApJ...841L...2H 2017ApJ...841L...2H).
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 I9 --- ID The KIC/EPIC identifier
11 A1 --- f_ID [d] Flag on ID (7)
13- 16 F4.1 mag gmag [13/19] The g band apparent magnitude
18- 21 A4 --- Tel Facility that obtained the data
23- 33 A11 "Y/M/D" Date UT date of the observation
35- 42 A8 --- Exp Number of exposures times the exposure time
44- 46 F3.1 arcsec Seeing [0.7/2.6] Seeing
48- 51 F4.2 --- Air [1/1.6] Average airmass
53- 55 I3 --- S/N [50/210] Signal-to-Noise (8)
57- 61 I5 K Teff-1D [10890/13620] Effective temperature
from 1D model
63- 65 I3 K e_Teff-1D [140/380] Uncertainty in Teff-1D
67- 71 F5.3 [cm/s2] logg-1D [7.7/8.5] log surface gravity from 1D model
73- 77 F5.3 [cm/s2] e_logg-1D [0.04/0.08] Uncertainty in logg-1D
79- 83 I5 K Teff-3D [10600/13590] Effective temperature
from 3D model
85- 89 F5.3 [cm/s2] logg-3D [7.7/8.5] log surface gravity from 3D model
91- 94 F4.2 Msun Mass [0.4/0.9] White dwarf mass
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Note (7):
d = One of the first six outbursting white dwarfs
(Bell+ 2015ApJ...809...14B 2015ApJ...809...14B ; Hermes+ 2015ApJ...810L...5H 2015ApJ...810L...5H ;
Bell+ 2016ApJ...829...82B 2016ApJ...829...82B ; 2017ASPC..509..303B 2017ASPC..509..303B)
Note (8): Computed using a 100-Angstrom-wide region of the continuum
centered at 4600 Angstroms.
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 9 I9 --- ID The KIC/EPIC identifier
11- 25 A15 --- Mode Mode
27- 37 F11.6 s LLS-Per [107.6/1769.1]? Linear Least-Squares period
39- 46 F8.6 s e_LLS-Per [0.00004/0.06]? Uncertainty in LLS-Per
48- 57 F10.5 uHz LLS-Freq [565.2/9286.3]? Linear Least-Squares frequency
59- 65 F7.5 uHz e_LLS-Freq [0.0006/0.05]? Uncertainty in LLS-Freq
67- 72 F6.3 --- LLS-Amp [0.09/24.2]? Linear Least-Squares amplitude (1)
74- 78 F5.3 --- e_LLS-Amp [0.02/0.5]? Uncertainty in LLS-Amp (1)
80- 85 F6.4 rad Phase ? Phase
87- 92 F6.4 rad e_Phase [0.001/0.06]? Uncertainty in Phase
94-103 F10.5 s Lor-Per [107.6/1769.1]? Lorentzian period
105-112 F8.5 s e_Lor-Per [0.0005/15]? Uncertainty in Lor-Per
114-118 F5.3 uHz HWHM [0.02/9.3]? Half-Width at Half-Maximum of
Lorentzian fit
120-126 F7.3 --- Lor-Amp [0.01/635.4]? Lorentzian amplitude;
in units of (parts per thousand)2
128-135 F8.4 uHz Split [1.3/139.3]? Splitting frequency
137-137 A1 --- f_Split [h?] h=indicates a harmonic
139-140 A2 --- l Spherical degree
142-143 A2 --- m Azimuthal order
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Note (1): In units of parts per thousand.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 20-Nov-2017