J/MNRAS/479/2909 Variability of Galactic Be stars using ASAS-3 (Bernhard+, 2018)
An investigation of the photometric variability of confirmed and
candidate Galactic Be stars using ASAS-3 data.
Bernhard K., Otero S., Hummerich S., Kaltcheva N., Paunzen E., Bohlsen T.
<Mon. Not. R. Astron. Soc., 479, 2909-2967 (2018)>
=2018MNRAS.479.2909B 2018MNRAS.479.2909B (SIMBAD/NED BibCode)
ADC_Keywords: Stars, Be ; Stars, variable ; Photometry, UBV
Keywords: stars: circumstellar matter - stars: early-type -
stars: emission-line, Be - stars: oscillations -
stars: variables: general
Abstract:
We present an investigation of a large sample of confirmed (N=233)
and candidate (N=54) Galactic classical Be stars (mean V magnitude
range of 6.4-12.6mag), with the main aim of characterizing their
photometric variability. Our sample stars were preselected among
early-type variables using light-curve morphology criteria.
Spectroscopic information was gleaned from the literature, and
archival and newly acquired spectra. Photometric variability was
analysed using archival ASAS-3 time-series data. To enable a
comparison of results, we have largely adopted the methodology of
Labadie-Bartz et al. (2017AJ....153..252L 2017AJ....153..252L, Cat. J/AJ/153/252), who
carried out a similar investigation based on KELT data. Complex
photometric variations were established in most stars: outbursts on
different time-scales (in 73±5 per cent of stars), long-term
variations (36±6 per cent), periodic variations on intermediate
time-scales (1±1 per cent), and short-term periodic variations
(6±3 per cent). 24±6 per cent of the outbursting stars
exhibit (semi)periodic outbursts. We close the apparent void of rare
outbursters reported by Labadie-Bartz et al. (2017AJ....153..252L 2017AJ....153..252L,
Cat. J/AJ/153/252) and show that Be stars with infrequent outbursts
are not rare. While we do not find a significant difference in the
percentage of stars showing outbursts among early-type, mid-type, and
late-type Be stars, we show that early-type Be stars exhibit much more
frequent outbursts. We have measured rising and falling times for
well-covered and well-defined outbursts. Nearly all outburst events
are characterized by falling times that exceed the rising times. No
differences were found between early-, mid-, and late-type stars; a
single non-linear function adequately describes the ratio of falling
time to rising time across all spectral subtypes, with the ratio being
larger for short events.
Description:
This work presents an investigation of a large sample of confirmed
(N=233) and candidate (N=54) Galactic Be stars, using archival
photometric and spectroscopic observations as well as newly acquired
spectra, with the main aim of describing their photometric
variability.
Our sample was initially recruited from a list of early-type variable
stars compiled by one of us (S.O.), which was assembled by a
systematic investigation of photometric time-series data from the All
Sky Automated Survey (Pojmanski, 2002AcA....52..397P 2002AcA....52..397P, Cat. II/264;
ASAS hereafter) archive.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 228 287 Essential data for our sample stars,
sorted by increasing right ascension
tabled1.dat 68 287 Colour indices and colour excesses for our sample
stars, sorted by increasing right ascension
refs.dat 178 117 References
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See also:
II/264 : ASAS Variable Stars in Southern hemisphere (Pojmanski+, 2002-2005)
Byte-by-byte Description of file: tablea1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Seq Sequential number
5- 19 A15 --- GSC Identification from the Guide Star Catalog
(GSC), version 1.2.
21- 53 A33 --- ONames Identification from the Henry Draper (HD)
catalogue or other conventional identifier
55- 56 I2 h RAh Right ascension (J2000) (1)
58- 59 I2 min RAm Right ascension (J2000) (1)
61- 66 F6.3 s RAs Right ascension (J2000) (1)
68 A1 --- DE- Declination sign (J2000)(1)
69- 70 I2 deg DEd Declination (J2000 (1)
72- 73 I2 arcmin DEm Declination (J2000) (1)
75- 79 F5.2 arcsec DEs Declination (J2000) (1)
81- 85 F5.2 mag Vmagl1 V magnitude range, as derived from ASAS-3 data
86 A1 --- --- [-]
87- 91 F5.2 mag Vmagu1 V magnitude range, as derived from ASAS-3 data
92 A1 --- n_Vmagl1 [*] Note on V magnitude range (2)
94- 98 F5.2 mag Vmagl2 V magnitude range, as gleaned from a star's
recorded photometric history
(cf. Section 2.5)
99 A1 --- --- [-]
100-104 F5.2 mag Vmagu2 V magnitude range, as gleaned from a star's
recorded photometric history
(cf. Section 2.5)
106-170 A65 --- SpType Spectral type(s) from the literature, with
references in refs.dat file
172 A1 --- subtype [EMLU] Subtype (3)
174-180 A7 --- Emission Emission flag (4)
182-193 A12 --- VarTypeL Variability type, following LB17 (5)
195-205 A11 --- VarTypeG Variability type, following the GCVS and VSX
classifications
206-217 F12.7 d Per ?=- Period, as derived from analysis of
ASAS-3 data
219-228 F10.7 d e_Per ? rms uncertainty on Period
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Note (1): From Hog et al., 2000A&A...355L..27H 2000A&A...355L..27H, Cat. I/259 (Tycho-2 catalogue).
Note (2): * for ranges that have been corrected for light contamination from
close neighbouring stars (cf. Section 2.5).
Note (3): Subtype as follows:
E = early
M = mid
L = late
U = unclassified
Note (4): Emission flag as follows:
l = emission confirmed in literature/BeSS spectra
s = emission confirmed in own spectra
la = emission confirmed in LAMOST spectra
u = emission confirmed from uvbyβ photometry)
Note (5): Variability type, following Labadie-bartz et al. (2017AJ....153..252L 2017AJ....153..252L,
Cat. J/AJ/153/252) as follows:
ObV = outbursts present
SRO = semiregular outbursts
LTV = long-term variability present
NRP = non-radial pulsator candidate (periodic variability with P≤2d)
IP = intermediate periodicity (periodic variability with 2<P≤200d)
EB = eclipsing binary
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Byte-by-byte Description of file: tabled1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Seq Sequential number
5- 19 A15 --- GSC Identification from the Guide Star Catalog
(GSC), version 1.2
21- 25 F5.2 mag (B-V)K ?=- (B-V) index, taken from Kharchenko
(2001KFNT...17e.409K 2001KFNT...17e.409K, Cat. I/280)
27- 31 F5.2 mag (B-V)GA ?=- (B-V) index, taken from the GCPD and/or
APASS (1)
33- 37 F5.2 mag (U-B)G ?=- (U-B) index, taken (with very few
exceptions) from the GCPD
39- 44 A6 --- SpTypeinp Spectral type and luminosity class (2)
46- 50 F5.2 mag (B-V)0sp ?=- (B-V)0 index, as derived from
the spectral type
52- 56 F5.2 mag (B-V)0pavg ?=- Average (B-V)0 index, as derived from
the available UBV and uvby data
58- 62 F5.2 mag E(B-V)sp ?=- Colour excess E(B-V), as derived from
spectroscopy
64- 68 F5.2 mag E(B-V)pavg ?=- Average colour excess E(B-V), as derived
from the available UBV and uvby data
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Note (1): When indices from both sources are available, average values have
been given.
Note (2): Spectral type and luminosity class used as input for obtaining the
spectroscopic (B-V)0 and E(B-V).
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Ref Reference code
5- 23 A19 --- BibCode BibCode
25- 55 A31 --- Aut Author's name
57-178 A122 --- Com Comments
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 11-May-2022