J/AJ/155/53 Outbursts and disk variability in Be stars (Labadie-Bartz+, 2018)
Outbursts and disk variability in Be stars.
Labadie-Bartz J., Chojnowski S.D., Whelan D.G., Pepper J., McSwain M.V.,
Borges Fernandes M., Wisniewski J.P., Stringfellow G.S., Carciofi A.C.,
Siverd R.J., Glazier A.L., Anderson S.G., Caravello A.J., Stassun K.G.,
Lund M.B., Stevens D.J., Rodriguez J.E., James D.J., Kuhn R.B.
<Astron. J., 155, 53-53 (2018)>
=2018AJ....155...53L 2018AJ....155...53L (SIMBAD/NED BibCode)
ADC_Keywords: Stars, Be ; Stars, variable ; Photometry ; Optical ;
Spectral types
Keywords: circumstellar matter - stars: emission-line, Be -
stars: variables: general - techniques: photometric -
techniques: spectroscopic
Abstract:
In order to study the growth and evolution of circumstellar disks around
classical Be stars, we analyze optical time-series photometry from the
KELT survey with simultaneous infrared and visible spectroscopy from the
Apache Point Observatory Galactic Evolution Experiment survey and Be Star
Spectra database for a sample of 160 Galactic classical Be stars. The
systems studied here show variability including transitions from a
diskless to a disk-possessing state (and vice versa), and persistent
disks that vary in strength, being replenished at either regularly or
irregularly occurring intervals. We detect disk-building events
(outbursts) in the light curves of 28% of our sample. Outbursts are
more commonly observed in early- (57%), compared to mid- (27%) and
late-type (8%) systems. A given system may show anywhere between 0 and
40 individual outbursts in its light curve, with amplitudes ranging up
to ∼0.5 mag and event durations between ∼2 and 1000 days. We study how
both the photometry and spectroscopy change together during active
episodes of disk growth or dissipation, revealing details about the
evolution of the circumstellar environment. We demonstrate that
photometric activity is linked to changes in the inner disk, and show
that, at least in some cases, the disk growth process is asymmetrical.
Observational evidence of Be star disks both growing and clearing from
the inside out is presented. The duration of disk buildup and dissipation
phases are measured for 70 outbursts, and we find that the average
outburst takes about twice as long to dissipate as it does to build up
in optical photometry. Our analysis hints that dissipation of the
inner disk occurs relatively slowly for late-type Be stars.
Description:
The Apache Point Observatory Galactic Evolution Experiment (APOGEE)
employs a 300 fiber spectroscopic instrument characterized by high
resolution (R∼22500), high signal-to-noise ratio (S/N>100), and H-band
near-infrared (NIR) coverage (1.51-1.70 µm; Majewski et al.
2017AJ....154...94M 2017AJ....154...94M; Wilson et al. 2010SPIE.7735E..1CW). The instrument
is attached to the Sloan Digital Sky Survey 2.5 m telescope (Gunn et al.
2006AJ....131.2332G 2006AJ....131.2332G). The APOGEE data presented here is from the 12th
data release of SDSS-III (Alam et al. 2015, Cat. V/147).
The Kilodegree Extremely Little Telescope (KELT) is a photometric
exoplanet transit 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 effective passband that KELT uses is roughly equivalent to
a broad R-band filter. KELT light curves use JD (TT) as the time system.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 77 78 Well-sampled and well-defined outbursts
table3.dat 102 160 APOGEE + KELT classical Be star sample
phot.dat 28 855040 The KELT light curves of all the sources
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See also:
III/17 : Early-Type Emission-Line Stars (Wackerling 1970)
III/180 : SS(77) Catalogue: new H-alpha em* in Milky Way
(Stephenson+ 1977)
V/15 : SAO and Supplementary Data (Ochsenbein 1980)
III/67 : Catalogue of Be stars (Jaschek+, 1982)
III/138 : Henry Draper Extension 2 (Cannon+ 1949; ADC 1989)
III/182 : HDE Charts: positions, proper motions (Nesterov+ 1995)
IV/25 : HD identifications for Tycho-2 stars (Fabricius+, 2002)
I/297 : NOMAD Catalog (Zacharias+ 2005)
V/125 : Photometry and Spectroscopy for Luminous Stars (Reed 2005)
J/A+A/451/1053 : Fundamental parameters of Be stars (Fremat+, 2006)
I/280 : All-Sky Compiled Catalogue of 2.5 million stars
(Kharchenko+ 2009)
B/mk : Catalogue of Stellar Spectral Classifications
(Skiff, 2009-2016)
V/147 : The SDSS Photometric Catalogue, Release 12 (Alam+, 2015)
J/A+AS/137/451 : Radial velocities. IX. (Grenier+, 1999)
J/A+A/451/1053 : Fundamental parameters of Be stars (Fremat+, 2006)
J/A+A/541/A34 : Spectral types of stars in CoRoT fields (Sebastian+, 2012)
J/AJ/149/7 : SDSS-III/APOGEE. I. Be stars (Chojnowski+, 2015)
J/AJ/153/174 : SDSS-III/APOGEE. II. The multi-epoch ABE sample
(Chojnowski+, 2017)
J/AJ/153/252 : Photometric variability of BeSS-KELT stars
(Labadie-Bartz+, 2017)
J/A+A/613/A70 : Be stars in the exofield of CoRoT. II. (Semaan+, 2018)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- ABE Outburst identifier (ABE-(A)NNN in Simbad)
5- 7 I3 d Rise [3/169] Rising time
9- 12 I4 d Fall [3/1281] Falling time
14- 18 F5.3 mag Amp [0.034/0.442] Photometric amplitude
20- 25 F6.1 d Date1 [4063/6982.5] Date of the beginning of rising
phase (JD-2450000)
27- 29 I3 d e_Date1 [1/199] Uncertainty in Date1
31- 36 F6.1 d Date2 [4075.5/6986.5] Date of the peak brightness
(JD-2450000)
38- 40 I3 d e_Date2 [1/172] Uncertainty in Date2
42- 47 F6.1 d Date3 [4108.3/7304.9] Date of the end of falling phase
(JD-2450000)
49- 51 I3 d e_Date3 [1/201] Uncertainty in Date3
53- 58 F6.3 mag Base [7.431/12.008] Baseline brightness (1)
60- 64 F5.3 mag e_Base [0.002/0.029] Uncertainty in Base
66- 71 F6.3 mag Brmax [7.122/11.95] Maximum brightness (1)
73- 77 F5.3 mag e_Brmax [0.003/0.058] Uncertainty in Brmax
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Note (1): The values reported for the baseline and maximum brightness are in
units of KELT instrumental magnitude, after subtraction of a constant offset
(in order to approximate V-band magnitudes).
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Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- ABE Outburst identifier (ABE-(A)NNN in Simbad)
5- 28 A24 --- Star Star name
30- 34 F5.2 mag Vmag [5.9/10.9] NOMAD V-band magnitude
36- 46 A11 --- SpType Spectral type
48- 55 A8 --- r_SpType Reference for SpType (1)
57- 68 A12 --- Class Effective temperature class
70- 71 I2 --- APOGEE [1/32] Number of APOGEE visits
73- 75 A3 --- Field KELT field
77- 87 A11 "date" Date1 The first date of KELT observations
89- 99 A11 "date" Date2 The last date of KELT observations
101-102 A2 --- Noutb Number of detected outbursts
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Note (1): Reference as follows:
1 = Nassau & Harris (1952ApJ...115..459N 1952ApJ...115..459N);
2 = Fremat et al. (2006, J/A+A/451/1053);
3 = Houk & Swift (1999, Cat. III/214);
4 = Skiff (2013, Cat. B/mk);
5 = Stephenson & Sanduleak (1977, Cat. III/180);
6 = Reed (2003, Cat. V/125);
7 = MacConnell (1968ApJS...16..275M 1968ApJS...16..275M);
8 = Ochsenbein (1980, Cat. V/15);
9 = Nesterov et al. (1995, Cat. III/182);
10 = Voroshilov et al. (1985, Cat. III/230);
11 = Kharchenko (2001, Cat. I/280);
12 = Alknis (1958TrRig...7...33A 1958TrRig...7...33A);
13 = Fabricius et al. (2002, Cat. IV/25);
14 = Clausen & Jensen (1979RA......9..479C 1979RA......9..479C);
15 = Bopp (1988AJ.....95.1543B 1988AJ.....95.1543B);
16 = Grillo et al. (1992ApJS...81..795G 1992ApJS...81..795G);
17 = Roslund (1963ArA.....3...97R 1963ArA.....3...97R);
18 = Grenier et al. (1999, J/A+AS/137/451);
19 = Stephenson & Sanduleak (1977PW&SO...2...71S 1977PW&SO...2...71S);
20 = Merrill & Burwell (1949ApJ...110..387M 1949ApJ...110..387M);
21 = Hardorp et al. (1959, Cat. III/76);
22 = Sebastian et al. (2012, J/A+A/541/A34);
23 = McCuskey (1959ApJS....4....1M 1959ApJS....4....1M);
24 = Uzpen et al. (2008ApJ...685.1157U 2008ApJ...685.1157U);
25 = Guetter (1968PASP...80..197G 1968PASP...80..197G);
26 = Morgan et al. (1955ApJS....2...41M 1955ApJS....2...41M);
27 = Turner (1976ApJ...210...65T 1976ApJ...210...65T);
28 = Radoslavova (1989AN....310..223R 1989AN....310..223R);
29 = Merrill et al. (1942ApJ....96...15M 1942ApJ....96...15M);
30 = Wackerling (1970, Cat. III/17);
31 = Christy (1977ApJ...217..127C 1977ApJ...217..127C);
32 = Reig et al. (2010A&A...522A.107R 2010A&A...522A.107R);
33 = Negueruela (2004AN....325..380N 2004AN....325..380N);
34 = Cannon & Mayall (1949, Cat. III/138);
35 = Turner (1993A&AS...97..755T 1993A&AS...97..755T);
36 = Popper (1950ApJ...111..495P 1950ApJ...111..495P);
37 = Walborn et al. (2010AJ....139.1283W 2010AJ....139.1283W);
New = Indicates that an object was discovered to be a Be star through
inspection of APOGEE spectra and is announced in Chojnowski et al.
(2015, J/AJ/149/7). These systems have neither an available literature
spectral type nor an optical spectrum acquired with APO-ARCES or the AO
long-slit spectrograph;
ARCES = The Astrophysical Research Consortium Echelle spectrograph;
AO = Adams Observatory.
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Byte-by-byte Description of file: phot.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- ABE Outburst identifier (ABE-(A)NNN in Simbad)
5- 13 F9.4 d JD [0/7122.25] Julian Date (JD-2450000.0)
15- 21 F7.4 mag KELTmag [-1.5855/16.0227] KELT apparent magnitude
23- 28 F6.4 mag e_KELTmag [0/4.1771] Uncertainty in KELTmag
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 01-Oct-2018