2012A&A...540A..53S


C.D.S. - SIMBAD4 rel 1.7 - 2020.04.09CEST16:51:20

2012A&A...540A..53S - Astronomy and Astrophysics, volume 540A, 53-53 (2012/4-1)

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. and RIDGWAY S.T.

Abstract (from CDS):

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. The LBOI observations suggest that the star's decretion disk was axisymmetric in 2010, has an system inclination angle near 45°, and a larger radius than previously reported. In addition, the Be star began an ``outburst'' at the beginning of our campaign, made visible by a brightening and reddening of the disk during our campaign and beyond. Our analyses of the new high resolution spectra disclosed many attributes also found from spectra obtained in 2001 (Chandra) and 2004 (XMM-Newton). As well as a dominant hot (≃14keV) thermal component, the familiar attributes included: (i) a fluorescent feature of Fe K even stronger than observed at previous times; (ii) strong lines of NVII and NeXI lines indicative of overabundances; and (iii) a subsolar Fe abundance from K-shell lines but a solar abundance from L-shell ions. We also found that two absorption columns are required to fit the continuum. While the first one maintained its historical average of 1x1021cm–2, the second was very large and doubled to 7.4x1023cm–2 during our X-ray observations. Although we found no clear relation between this column density and orbital phase, it correlates well with the disk brightening and reddening both in the 2010 and earlier observations. Thus, the inference from this study is that much (perhaps all?) of the X-ray emission from this source originates behind matter ejected by γ Cas into our line of sight.

Abstract Copyright:

Journal keyword(s): stars: individual: γ Cassiopeiae - stars: emission-line, Be - stars: activity - stars: winds, outflows - matter circumstellar

VizieR on-line data: <Available at CDS (J/A+A/540/A53): table2.dat>

Status at CDS:  

Simbad objects: 18

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Number of rows : 18

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 * ups02 Cas Pe* 00 56 39.9041301647 +59 10 51.800571997   5.581 4.622     G8.5IIIbFe-0.5 207 0
2 * gam Cas Be* 00 56 42.5317 +60 43 00.265 1.18 2.29 2.39 2.32 2.40 B0.5IVpe 1130 2
3 NAME Magellanic Clouds GrG 03 00 -71.0           ~ 5552 1
4 HD 36705 TT* 05 28 44.8916324761 -65 26 55.289846904 8.259 7.856 6.999 6.496 5.993 K0V 925 0
5 * ome CMa Be* 07 14 48.6538664 -26 46 21.609714 2.90 3.64 3.82 3.80 3.90 B2.5Ve 328 0
6 NGC 4609 OpC 12 42 18 -62 59.7   7.32 6.9     ~ 65 0
7 HD 110432 Be* 12 42 50.2655719413 -63 03 31.048323668 4.79 5.58 5.31     B0.5IVpe 266 0
8 HD 119682 Be* 13 46 32.5707617771 -62 55 24.153203600 7.26 7.978 7.901 8.72   B0Ve 51 0
9 * mu. Cen Be* 13 49 36.9886294 -42 28 25.429594 2.37 3.27 3.43 3.41 3.50 B2Vnpe 411 0
10 * del Sco SB* 16 00 20.00528 -22 37 18.1431 1.30 2.20 2.32 2.36 2.49 B0.3IV 690 0
11 HD 150608 * 16 43 47.5938191703 -38 09 22.874048527   5.985 6.046     B9II/III 22 0
12 HD 157832 Be* 17 27 54.8113464489 -47 01 34.399141463 5.81 6.636 6.663     B2ne 52 1
13 HD 161103 Be* 17 44 45.7657852846 -27 13 44.482410725 8.44 9.23 9.13 9.12   B0.5III/IVe 72 0
14 NGC 6649 OpC 18 33 27 -10 24.2   10.35 8.9     ~ 102 0
15 3XMM J183327.7-103524 HXB 18 33 27.7663679366 -10 35 24.440275505     11.9     B0.5Ve 22 0
16 NGC 6649 9 Be* 18 33 28.3005371830 -10 24 08.760637022   12.98 11.76 10.6   B0Ve 13 0
17 BD+47 3129 Em* 20 30 30.8457252623 +47 51 50.718662840 8.95 9.57 9.27     B0 31 0
18 V* AE Aqr DQ* 20 40 09.1598509019 -00 52 15.057042857   12.46 10.40   10.191 K3-5IV/V 602 0

    Equat.    Gal    SGal    Ecl

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2020.04.09-16:51:20

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