J/A+A/540/A53 γ Cas radial velocity curve (Smith+, 2012)
The relationship between γ Cassiopeiae's X-ray emission and its
circumstellar environment.
Smith M.A., Lopes de Oliveira R., Motch C., Henry G.W., Richardson N.D.,
Bjorkman K.S., Stee P., Mourard D., Monnier J.D., Che X., Buecke R.,
Pollmann E., Gies D.R., Schaefer G.H., ten Brummelaar T., McAlister H.A.,
Turner N.H., Sturmann J., Sturmann L., Ridgway S.T.
<Astron. Astrophys., 540, A53 (2012)>
=2012A&A...540A..53S 2012A&A...540A..53S
ADC_Keywords: Stars, Be ; Stars, emission ; Radial velocities
Keywords: stars: individual: γ Cassiopeiae - stars: emission-line, Be -
stars: activity - stars: winds, outflows - circumstellar matter
Abstract:
γ Cas is the prototypical classical Be star and is recently
best known for its variable hard X-ray emission. To elucidate the
reasons for this emission, we mounted a multiwavelength campaign in
2010 centered around four XMM-Newton observations. The observational
techniques included long baseline optical interferometry (LBOI) from
two instruments at CHARA, photometry carried out by an automated
photometric telescope and Hα observations. Because γ Cas
is also known to be in a binary, we measured radial velocities from
the Hα line and redetermined its period as 203.55±0.20 days
and its eccentricity as near zero.
Description:
Our LBOI observations were conducted in the infrared using Georgia
State University's Center for High Angular Resolution Astronomy
(CHARA) array facility on Mt. Wilson. CHARA is an interferometric
array of six 1-m telescopes configured in a Y-shaped pattern with
baselines of up to 330m for maximum spatial resolution. Our
observations utilized two new-generation instruments for imaging of
γ Cas's decretion disk: the Michigan Infrared Combiner (MIRC) in
the H-band (1.64um) and the Visible spEctroGraph and polArimeter
(VEGA), which became operational in 2009.
Our optical continuum observations of γ Cas were made in the
standard Johnson V and B band filters on every available photometric
night (sometimes several times per night) using the 0.4m T3 Automated
Photometric Telescope (APT) located at Fairborn Observatory in the
Patagonia mountains in southern Arizona.
To support this program we made use of 306 echelle spectra of γ
Cas taken in a long-term monitoring program with the spectrograph
fiber-fed from the Cassegrain focus of the 1.06-m telescope at Ritter
Observatory (administered by the University of Toledo) in 2009
December and the second half of 2010.
We conducted four XMM-Newton observations under the auspices of Guest
Investigator cycle A09. These were carried out on 2010 July 7 (ObsID
0651670201; referred to here as OBS1), July 24 (0651670301; OBS2),
August 2 (0651670401; OBS3), and August 24 (0651670501; OBS4),
beginning on MJD dates 55384.30, 55401.15, 55410.77, and
55428.09, respectively.
Objects:
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RA (2000) DE Designation(s)
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00 56 42.53 +60 43 00.3 gamma Cas = HR 264
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 38 301 Ritter and Dobson/RB radial velocities
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See also:
J/A+A/284/515 : Long-term periodic variability in gamma Cas (Telting+ 1994)
J/ApJ/647/1375 : BV light curves of γ Cas (Smith+, 2006)
J/A+A/537/A59 : Radial velocities of gamma Cas (Nemravov+, 2012)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 9 F9.3 --- RHJD Reduced Julian Date (HJD-2400000)
11- 15 F5.2 km/s HRV Heliocentric Radial velocity
17- 20 F4.2 km/s e_HRV Error in HRV
22- 25 F4.2 -- Phase Binary orbit phase (2)
27- 31 F5.2 km/s O-C Observed - Computed (modeled) RV
33- 38 A6 -- Source Source (observatory) for RV (1)
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Note (1): Source is:
Ritter = Ritter observatory
RB = Hamburg Dobson Telescope
Note (2): on the basis of the orbital solution:
K = 3.79±0.08km/s
e = 0
P = 203.55±0.21d
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Acknowledgements:
M.A. Smith, msmith(at)stsci.edu
(End) Patricia Vannier [CDS] 29-May-2012