2021ApJ...915...13S


Query : 2021ApJ...915...13S

2021ApJ...915...13S - Astrophys. J., 915, 13-13 (2021/July-1)

Automated photometry of γ Cassiopeiae: the last roundup.

SMITH M.A. and HENRY G.W.

Abstract (from CDS):

γ Cassiopeiae (B0.5IVe) is the noted prototype of a subgroup of classical Be stars exhibiting hard thermal X-ray emission. This paper reports results from a 23 yr optical campaign on this star with an automated photometric telescope (APT). A series of unstable long cycles of length 56-91 days has nearly ceased over the last decade. Also, we revise the frequency of the dominant coherent signal at 0.82238 days–1. This signal's amplitude has nearly disappeared in the last 15 yr but has somewhat recovered its former strength. We confirm the presence of secondary nonradial pulsation signals found by other authors at frequencies 1.24, 2.48, and 5.03 days–1. The APT data from intensively monitored nights reveal rapidly variable amplitudes among these frequencies. We show that peculiarities in the 0.82 days–1 waveform exist that can vary even over several days. Although the 0.82 days–1 frequency is near the star's presumed rotational frequency, because of its phase slippage with respect to a dip pattern in its far-UV light curve, it is preferable to consider the UV pattern, not the 0.82 days–1 signal, as associated with rotational modulation. We also find hints of the UV dip pattern in periodograms of seasonal data early in our program.

Abstract Copyright: © 2021. The American Astronomical Society. All rights reserved.

Journal keyword(s): B stars

VizieR on-line data: <Available at CDS (J/ApJ/915/13): table1.dat>

Simbad objects: 11

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Number of rows : 11
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026
#notes
1 * ups02 Cas Pe* 00 56 39.9051464088 +59 10 51.805287084   5.581 4.622     G8.5IIIbFe-0.5 233 0
2 * gam Cas HXB 00 56 42.5310945 +60 43 00.264089 1.18 2.29 2.39 2.32 2.40 B0.5IVpe 1253 0
3 HD 6210 PM* 01 04 19.4510863152 +61 34 48.662237964   6.386 5.833     F6V 91 0
4 * phi Per Be* 01 43 39.6379691568 +50 41 19.433124998 3.10 4.02 4.06 3.90 3.88 B1.5V:e-shell 594 0
5 HD 41335 Be* 06 04 13.5003372120 -06 42 32.225392980 4.31 5.14 5.21 5.13 5.09 B1V 314 0
6 HD 58978 Be* 07 26 59.4826856664 -23 05 09.689679528 4.51 5.45 5.56 7.05   B0.5IVe 248 0
7 NGC 3766 OpC 11 36 13.5 -61 36 42   5.66 5.3     ~ 222 0
8 HD 163868 Be* 17 59 56.4314226144 -33 24 29.980813608 6.69 7.311 7.354     B5Ve 72 0
9 * f01 Cyg Be* 20 59 49.5541247496 +47 31 15.363746436 3.77 4.71 4.75 4.62 4.63 B1.5Vnne 514 0
10 * bet Cep bC* 21 28 39.5968513 +70 33 38.574681 2.05 3.01 3.23 3.33 3.55 B0.5IIIs 756 0
11 * pi. Aqr Be* 22 25 16.6230017410 +01 22 38.634449478 3.64 4.60 4.64 4.48 4.48 B1III-IVe 436 0

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