J/A+A/562/A107 σ Gem V-band differential light curve (Kajatkari+, 2014)
Spot activity of the RS Canum Venaticorum star sigma Geminorum.
Kajatkari P., Hackman T., Jetsu L., Lehtinen J., Henry G.W.
<Astron. Astrophys. 562, A107 (2014)>
=2014A&A...562A.107K 2014A&A...562A.107K
ADC_Keywords: Stars, variable ; Photometry
Keywords: stars: activity - starspots - stars: individual: sigma Geminorum
Abstract:
We model the photometry of RS CVn star sigma Geminorum to obtain new
information on the changes of the surface starspot distribution, that
is, activity cycles, differential rotation, and active longitudes.
We used the previously published continuous period search (CPS) method
to analyse V-band differential photometry obtained between the years
1987 and 2010 with the T3 0.4m Automated Telescope at the Fairborn
Observatory. The CPS method divides data into short subsets and then
models the light-curves with Fourier-models of variable orders and
provides estimates of the mean magnitude, amplitude, period, and
light-curve minima. These light-curve parameters are then analysed for
signs of activity cycles, differential rotation and active longitudes.
Description:
The included files present the differential Johnson V-band photometry
of the RS CVn star sigma Geminorum, using the star HR 2896 as the
comparison star, and the numerical results of our analysis of the same
photometry.
The analysis has been performed using our previously published
continuous period search (CPS) method, described in detail in Lehtinen
et al., 2011, Cat. J/A+A/527/A136.
Objects:
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RA (2000) DE Designation(s)
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07 43 18.73 +28 53 00.6 sigma Gem = HD 62044
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
phot.dat 22 2459 Differential photometry of sigma Gem
res.dat 185 878 *Numerical results of the CPS analysis
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Note on res.dat: Continuous Period Search analysis: Each line consists of
numerical results for one single dataset.
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See also:
J/A+AS/123/209 : Radial velocity curve of Sigma Gem (Duemmler+ 1997)
J/A+A/527/A136 : HD 116956 V-band differential light curve (Lehtinen+, 2011)
Byte-by-byte Description of file: phot.dat
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Bytes Format Units Label Explanations
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1- 12 F12.4 d HJD Heliodentric Julian Date
14- 19 F6.3 mag DVmag Differential V-band photometry
21- 22 I2 --- SEG [1/23] Segment number (column added at CDS)
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Byte-by-byte Description of file: res.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- SEG [1/23] Segment number
4- 13 F10.4 d t0 1st timepoint in SEG (HJD-2400000)
15- 16 I2 --- SET [1/65] Dataset number
18- 27 F10.4 d t1 1st timepoint in SET (HJD-2400000)
29- 38 F10.4 d tn Last timepoint in SET (HJD-2400000)
40- 49 F10.4 d tau Mean epoch τ of SET (HJD-2400000)
51 I1 --- IND [0/1] Independency of SET (1=independent)
53- 54 I2 --- n Number of observations in SET
56- 62 F7.4 mag my Mean of observations in SET
64- 70 F7.4 mag e_my Standard deviation of observations in SET
72 I1 --- K [0/2] Light curve modelling order
74- 80 F7.4 mag se [0.002/0.020] Standard deviation of residuals
82- 89 F8.4 d TC [-2/191] Timescale of change
91- 97 F7.4 mag M [-1.16/-0.98] Light curve mean
99-105 F7.4 mag e_M [0.0006/0.0144] Error of M
107 I1 --- q_M [0/1] Reliability of M (1=unreliable)
109-115 F7.4 d Per [14/26]?=-1 Period of light curve in SET
117-123 F7.4 d e_Per ?=-1 Error of Per
125 I1 --- q_Per [0/1] Reliability of Per (1=unreliable)
127-133 F7.4 mag Amp [0.01/0.15]?=-1 Light curve amplitude
135-141 F7.4 mag e_Amp ?=-1 Error of Amp
143 I1 --- q_Amp [0/1] Reliability of Amp (1=unreliable)
145-154 F10.4 d tmin1 ?=-1 Epoch of primary minimum (HJD-2400000)
156-162 F7.4 d e_tmin1 ?=-1 Error of tmin1
164 I1 --- q_tmin1 [0/1] Reliability of tmin1 (1=unreliable)
166-175 F10.4 d tmin2 ?=-1 Epoch of secondary minimum (HJD-2400000)
177-183 F7.4 d e_tmin2 ?=-1 Error of tmin2
185 I1 --- q_tmin2 [0/1] Reliability of tmin2 (1=unreliable)
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Acknowledgements:
Perttu Kajatkari, perttu.kajatkari(at)helsinki.fi
(End) Perttu Kajatkari [Univ. of Helsinki], Patricia Vannier [CDS] 18-Nov-2013