J/A+A/559/A97 II Pegasus photometry during 1979-2010 (Lindborg+, 2013)
Multiperiodicity, modulations and flip-flops in variable star light curves.
II. Analysis of II Pegasus photometry during 1979-2010.
Lindborg M., Mantere M.J., Olspert N., Pelt J., Hackman T., Henry G.W.,
Jetsu L., Strassmeier K.G.
<Astron. Astrophys. 559, A97 (2013)>
=2013A&A...559A..97L 2013A&A...559A..97L
ADC_Keywords: Stars, variable ; Photometry
Keywords: stars: activity - techniques: photometry - starspots - stars: imaging
Abstract:
According to earlier Doppler images of the magnetically active primary
giant component of the RS CVn binary II Peg, the surface of the star
was dominated by one single active longitude that was clearly drifting
in the rotational frame of the binary system during 1994-2002; later
imaging for 2004-2010, however, showed decreased and chaotic spot
activity, with no signs of the drift pattern. Here we set out to
investigate from a more extensive photometric dataset whether such a
drift is a persistent phenomenon, in which case it could be due to
either an azimuthal dynamo wave or an indication of the binary system
orbital synchronization still being incomplete.
We analyse the datasets using the Carrier Fit method (hereafter CF),
especially suitable for analyzing time series in which a fast clocking
frequency (such as the rotation of the star) is modulated with a
slower process (such as the stellar activity cycle).
Description:
We combine all collected photometric data into one single data set,
and analyze it with the Carrier Fit (CF) method.
The first data set (hereafter DATA1), published and analyzed by Rodono
et al. (2000A&A...358..624R 2000A&A...358..624R), covers the years 1973-1998. The second
data set (hereafter DATA2) was published by Messina
(2008A&A...480..495M 2008A&A...480..495M) covering the years 1992-2004, therefore partly
overlapping with DATA1. The third data set (hereafter DATA3) consists
of unpublished observations with the Wolfgang-Amadeus, the university
of Potsdam/Vienna twin automatic photoelectric telescope (APT),
covering the years 1996-2009, again partially overlapping with the
previous datasets. The fourth dataset (hereafter DATA4) was obtained
with the Tennessee State University T3 0.4-m Automated Photometric
Telescope at Fairborn Observatory in Arizona, covering the time span
of 1987-2010 (see also Roettenbacher et al. 2011AJ....141..138R 2011AJ....141..138R, for
another analysis of the same dataset).
Objects:
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RA (2000) DE Designation(s)
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23 55 04.05 +28 38 01.2 HD 224085 = V* II Peg
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 26 100000 Global Carrier Fit model for II Peg photometry
during 1979-2010
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See also:
J/A+A/553/A40 : UBVI light curves of FK Com (Hackman+, 2013)
J/A+A/480/495 : Patterns of color variations in close binaries (Messina, 2008)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 16 F16.8 d HJD [2444168/2455384] Heliocentric Julian date
19- 26 F8.6 mag Vmag [7.22/8.00] V magnitude
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Acknowledgements:
Marjaana Lindborg, marjaana.lindborg(at)helsinki.fi
References:
Pelt et al., Paper I 2011A&A...535A..23P 2011A&A...535A..23P
(End) Patricia Vannier [CDS] 28-Oct-2013