J/A+A/553/A40 UBVI light curves of FK Com (Hackman+, 2013)
Flip-flops of FK Comae Berenices.
Hackman T., Pelt J., Mantere M.J., Jetsu L., Korhonen H., Granzer T.,
Kajatkari P., Lehtinen J., Strassmeier K.G.
<Astron. Astrophys. 553, A40 (2013)>
=2013A&A...553A..40H 2013A&A...553A..40H
ADC_Keywords: Stars, variable ; Photometry, UBV
Keywords: stars: late-type - stars: activity - starspots - dynamo -
stars: individual: FK Comae Berenices
Abstract:
We apply the continuous period search and carrier fit methods on
long-term standard Johnson-Cousins V-observations from the years
1995-2010. The observations were carried out with two automated
photometric telescopes, Phoenix-10 and Amadeus T7 located in Arizona.
We identify complex phase behaviour in 6 of the 15 analysed data
segments. We identify five flip-flop events and two cases of phase
jumps, where the phase shift is Δφ<0.4. In addition we
see two mergers of spot regions and two cases where the apparent phase
shifts are caused by spot regions drifting with respect to each other.
Furthermore we detect variations in the rotation period corresponding
to a differential rotation coefficient of |k|>0.031.
Description:
Differential Johnson V- and B-photometry of the star FK Comae (HD
117555) from automated photometric telescopes are presented. HD 117567
was used as the comparison star. Missing observations are denoted as
"99.0000".
Objects:
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RA (2000) DE Designation(s)
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13 30 46.80 +24 13 57.8 FK Com = HD 117555
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
vimag.dat 32 3151 V and I photometry
ubvmag.dat 39 1678 U, B and V photometry
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See also:
J/A+A/278/449 : Long-term photometry of FK Com (Jetsu+ 1993)
J/A+AS/103/183 : UVBRI photometry of FK Com (Jetsu+ 1994)
J/A+A/374/1049 : Photometry of FK Com for 1993-2001 (Korhonen+, 2001)
J/A+A/390/179 : Study of FK Comae Berenices. IV. (Korhonen+ 2002)
J/A+A/467/229 : UBV photometry of FK Com and HD 199178 (Panov+, 2007)
J/A+A/476/881 : Differential photometry of FK Com (Korhonen+, 2007)
Byte-by-byte Description of file: vimag.dat
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Bytes Format Units Label Explanations
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1- 14 F14.6 d HJD [2450850/2455298] Heliocentric Julian date
17- 23 F7.4 mag Vmag ?=99 Johnson V magnitude
26- 32 F7.4 mag Imag ?=99 Cousins I magnitude
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Byte-by-byte Description of file: ubvmag.dat
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Bytes Format Units Label Explanations
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1- 12 F12.4 d HJD [2449876/2453195] Heliocentric Julian date
15- 21 F7.4 mag Umag ?=99 Johnson U magnitude
24- 30 F7.4 mag Bmag ?=99 Johnson B magnitude
33- 39 F7.4 mag Vmag ?=99 Johnson V magnitude
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Acknowledgements:
Thomas Hackman, Thomas.Hackman(at)helsinki.fi
(End) Thomas Hackman [FINCA, Finland], Patricia Vannier [CDS] 19-Mar-2013