J/AJ/153/252 Photometric variability of BeSS-KELT stars (Labadie-Bartz+, 2017)
Photometric variability of the Be star population.
Labadie-Bartz J., Pepper J., McSwain M.V., Bjorkman J.E., Bjorkman K.S.,
Lund M.B., Rodriguez J.E., Stassun K.G., Stevens D.J., James D.J.,
Kuhn R.B., Siverd R.J., Beatty T.G.
<Astron. J., 153, 252-252 (2017)>
=2017AJ....153..252L 2017AJ....153..252L (SIMBAD/NED BibCode)
ADC_Keywords: Stars, Be ; Stars, variable ; Photometry, VRI ; Spectral types ;
Photometry, infrared
Keywords: stars: emission-line, Be - stars: oscillations -
stars: variables: general - techniques: photometric -
techniques: spectroscopic
Abstract:
Be stars have generally been characterized by the emission lines in
their spectra, and especially the time variability of those
spectroscopic features. They are known to also exhibit photometric
variability at multiple timescales, but have not been broadly compared
and analyzed by that behavior. We have taken advantage of the advent
of wide-field, long-baseline, and high-cadence photometric surveys
that search for transiting exoplanets to perform a comprehensive
analysis of brightness variations among a large number of known Be stars.
The photometric data comes from the KELT transit survey, with a
typical cadence of 30 minutes, a baseline of up to 10 years,
photometric precision of about 1%, and coverage of about 60% of the
sky. We analyze KELT light curves of 610 known Be stars in both the
northern and southern hemispheres in an effort to study their
variability. Consistent with other studies of Be star variability, we
find most of the stars to be photometrically variable. We derive lower
limits on the fraction of stars in our sample that exhibit features
consistent with non-radial pulsations (25%), outbursts (36%), and
long-term trends in the circumstellar disk (37%), and show how these
are correlated with spectral sub-types. Other types of variability,
such as those owing to binarity, are also explored. Simultaneous
spectroscopy for some of these systems from the Be Star Spectra
database allow us to better understand the physical causes for the
observed variability, especially in cases of outbursts and changes in
the disk.
Description:
Kilodegree Extremely Little Telescope (KELT) is a photometric survey
using two small-aperture (42 mm) wide-field (26°x26°) telescopes,
with a northern location at Winer Observatory in Arizona in the United
States, and a southern location at the South African Astronomical
Observatory near Sutherland, South Africa.
The Be Star Spectra (BeSS) database is a continually updated catalog
that attempts to include all known Be stars, as well as their stellar
parameters. This catalog is based primarily on the catalog of classical
Be stars published by Jaschek et al. (1982, Cat. III/67) but also
includes more recently discovered Be stars from a variety of sources
(e.g., Neiner et al. 2005ApJS..156..237N 2005ApJS..156..237N; Martayan et al.
2006A&A...445..931M 2006A&A...445..931M).
From the BeSS database, we compiled a list of all the classical Be stars
with 7<V<13, which included 1362 unique objects. This magnitude range
was chosen to align with KELT's magnitude limits. This subset was then
cross-matched with the KELT catalog, and 610 unique objects that exist
in both data sets were recovered. Of the 610 stars in this sample, 374
are observed by KELT North, 206 are observed by KELT South, and 30 are
observed by both KELT North and South (the joint field J06).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 282 610 Table of BeSS-KELT stars with variable type
classifications
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See also:
III/67 : Catalogue of Be stars (Jaschek+, 1982)
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
J/A+A/335/565 : Be stars variability (Hubert+ 1998)
J/AJ/149/7 : SDSS-III/APOGEE. I. Be stars (Chojnowski+, 2015)
http://basebe.obspm.fr : The BeSS database
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- BKNum [0/609] Internal identifier
5- 12 F8.4 deg RAdeg Right Ascension in decimal degrees (J2000) (1)
14- 21 F8.4 deg DEdeg Declination in decimal degrees (J2000) (1)
23- 27 F5.2 mag Vmag [6.03/12.81] V band magnitude (1)
29- 38 A10 --- SpType Spectral type (1)
40- 61 A22 --- ID Common identifier (1)
62- 65 I4 --- NSpec [0/3317] Number of archival BeSS spectra
67- 70 I4 km/s vsini [5/500]? BeSS rotational velocity
72-106 A35 --- KeID KELT eastern orientation data file identifier
108-142 A35 --- KwID KELT western orientation data file identifier
144-148 F5.2 mag Kemag [8.69/18.16]? KELT eastern orientation
instrumental magnitude
150-154 F5.2 mag Kwmag [8.29/16.14]? KELT western orientation
instrumental magnitude
156-163 F8.4 deg GLON Galactic longitude
165-172 F8.4 deg GLAT Galactic latitude
174-179 F6.3 mag Jmag [4.303/11.927] 2MASS J band magnitude (2)
181-186 F6.3 mag Hmag [3.546/11.822] 2MASS H band magnitude (2)
188-193 F6.3 mag Ksmag [3.326/11.686]? 2MASS Ks band magnitude (2)
195-200 F6.3 mag W1mag [3.138/11.525]? WISE 3.4µm band magnitude (3)
202-207 F6.3 mag W2mag [1.585/11.32]? WISE 4.6µm band magnitude (3)
209-214 F6.3 mag W3mag [-0.653/11.207]? WISE 12µm band magnitude (3)
216-221 F6.3 mag W4mag [-2.078/9.408]? WISE 22µm band magnitude (3)
223-227 F5.2 mag NUVmag [10.55/19.1]? GALEX NUV band magnitude (4)
229-233 F5.2 mag FUVmag [11.80/17.81]? GALEX FUV band magnitude (4)
235-245 F11.7 d Per1 [0.14205/205.99]? First period
247-256 F10.6 d Per2 [0.20635/192.70125]? Second period
257-266 F10.6 d Per3 [6.57901/127.10082]? Third period
268-282 A15 --- VType Variable type(s) (5)
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Note (1): Celestial coordinates, identifiers, spectral types, and V-band
magnitudes are gathered from the BeSS database
(http://basebe.obspm.fr).
Note (2): Skrutskie et al. (2006, Cat. VII/233).
Note (3): Wright et al. (2010AJ....140.1868W 2010AJ....140.1868W).
Note (4): Martin et al. (2005ApJ...619L...1M 2005ApJ...619L...1M).
Note (5): Variable types followed by "?" indicate some uncertainty in the
ascribed characteristic.
Variable type as follows:
ObV = Outburst Variation - outbursts are present in the raw light curve;
SRO = Semi-Regular Outbursts - outbursts occur with some regularity;
LTV = Long Term Variation - long term variability in the raw light curve;
NRP = Non-Radial Pulsator candidate - shows periodic variability at
timescales of less than 2 days;
IP = Intermediate Periodicity - shows periodic variability at
timescales greater than 2 days;
EB = Eclipsing Binary;
DW(S/I) = Double Wave - indicates double-waved modulation at (S)hort
or (I)ntermediate periods;
SAT = Saturated - saturation issues in the KELT photometry make
analysis of this star intractable at the present time.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 30-Apr-2018