J/ApJ/915/13 1997-2019 automated B,V phot. of gam Cas (Smith+, 2021)
Automated photometry of γ Cassiopeiae: the last roundup.
Smith M.A., Henry G.W.
<Astrophys. J., 915, 13 (2021)>
=2021ApJ...915...13S 2021ApJ...915...13S
ADC_Keywords: Photometry, UBV; Stars, Be
Keywords: B stars
Abstract:
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 23yr optical campaign on this star with an
automated photometric telescope (APT). A series of unstable long
cycles of length 56-91days has nearly ceased over the last decade.
Also, we revise the frequency of the dominant coherent signal at
0.82238/days. This signal's amplitude has nearly disappeared in the
last 15yr 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 5.03days-1. The APT data from
intensively monitored nights reveal rapidly variable amplitudes among
these frequencies. We show that peculiarities in the 0.82days-1
waveform exist that can vary even over several days. Although the
0.82days-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 0.82days-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.
Description:
We have been conducting Johnson B and V photometric observations of
γ Cas since 1997 with the T3 0.4m automated photometric
telescope (APT) facility at Fairborn Observatory in southern Arizona.
Each observation of γ Cas, which we refer to as a group
observation, consists of the mean of three B and V differential
measurements of γ Cas with respect to its comparison star
(HD6210) and the mean of two measurements of the check star (HD5395)
with respect to the comparison star.
In this paper we present our final 1997-2019 data set for γ Cas,
consisting of 5554 observations in the B passband and 5488 in the V
passband.
Objects:
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RA (ICRS) DE Designation(s)
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00 56 42.53 +60 43 00.2 γ Cas = * gam Cas
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 38 5708 Photometric observations of γ Cas for
seasons 1997-2019
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See also:
J/ApJ/647/1375 : BV light curves of γ Cas (Smith+, 2006)
J/ApJ/686/1280 : Discovery of hot subdwarf companion to FY CMa (Peters+, 2008)
J/ApJ/760/10 : BV light curves of γ Cas (1997-2011) (Henry+, 2012)
J/A+A/537/A59 : Radial velocities of gamma Cas (Nemravov+, 2012)
J/A+A/540/A53 : γ Cas radial velocity curve (Smith+, 2012)
J/ApJ/765/2 : FUV radial velocities of 59 Cyg (Peters+, 2013)
J/A+A/613/A70 : Be stars in the exofield of CoRoT. II. (Semaan+, 2018)
J/A+A/640/A36 : OB stars TESS phot. & high-res. spectroscopy (Bowman+, 2020)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 10 F10.4 d HJD [50718.69/58888.6] Reduced Julian Date;
HJD-2400000)
12- 17 F6.3 mag VarB [-4.4/-4.2]?=99.999 Variable - Comparison (HD 6210)
differential magnitude in B (1)
19- 24 F6.3 mag VarV [-3.8/-3.6]?=99.999 Variable - Comparison (HD 6210)
differential magnitude in V (1)
26- 31 F6.3 mag ChkB [-0.83/-0.78]?=99.999 Check (HD 5395) - Comparison
differential magnitude in B (1)
33- 38 F6.3 mag ChkV [-1.25/-1.19]?=99.999 Check (HD 5395) - Comparison
differential magnitude in V (1)
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Note (1): The '99.999' signifies that the differential magnitude was discarded
because its internal standard deviation exceeded 0.01mag.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 14-Dec-2022