Query : 2012A&A...542A..38L

2012A&A...542A..38L - Astronomy and Astrophysics, volume 542A, 38-38 (2012/6-1)

Spot activity of LQ Hydrae.


Abstract (from CDS):

We investigate the spot activity of the young magnetically active main sequence star LQ Hya. Our aims are to identify possible active longitudes, estimate the differential rotation, and study long and short term changes in the activity. Our analysis is based on 24 years of Johnson V-band photometry of LQ Hya obtained with the T3 0.4m Automated Telescope at the Fairborn Observatory. We use the previously published continuous period search (CPS) method to model the evolution of the light curve of LQ Hya. The CPS fits a Fourier series model to short overlapping subsets of data. This enables us to monitor the evolution of the light curve and thus the spot configuration of the star with a higher time resolution. We find seasonal variability in the mean level and amplitude of the light curve of LQ Hya. The variability of the light curve amplitude seems not to be cyclic, but the long-term variations in the mean magnitude may be indicative of an approximately 13 year cycle. However, because of the limited length of the observed time series, it is not yet possible to determine whether this structure really represents an activity cycle. Based on fluctuations of the light curve period, we estimate the differential rotation of the star to be small, and the star is potentially very close to a rigid rotator. We search for active longitudes from the inferred epochs of the light curve minima. We find that on time scales up to six months there are typically one or two relatively stable active areas on the star with limited phase migration. On the other hand, on time scales longer than one year, no stable active longitudes have been present except for the period between 2003 and 2009 and possibly also some time before 1995. Neither do we find any signs of flip-flops with a regular period. The mean time scale of change of the light curve during the observation period is determined to be of the same order of magnitude as the estimated convective turnover time for the star.

Abstract Copyright:

Journal keyword(s): stars: activity - starspots - stars: individual: LQ Hya

VizieR on-line data: <Available at CDS (J/A+A/542/A38): lqhya.dat results.dat>

Simbad objects: 6

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Number of rows : 6
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
1 IC 2391 OpC 08 41 10.1 -52 59 28           ~ 806 0
2 HD 82428 * 09 31 38.9869489560 -10 33 07.314739956   6.383 6.123     WN 43 0
3 HD 82477 PM* 09 31 55.7092342488 -10 22 13.234550052   7.312 6.124     K2III 29 0
4 V* LQ Hya BY* 09 32 25.5683895648 -11 11 04.692242760 9.316 8.761 7.891 7.288 6.815 K1Vp 446 0
5 HD 116956 BY* 13 25 45.5320130664 +56 58 13.776984840 8.540 8.090   6.8   G9V 123 0
6 HD 224085 RS* 23 55 04.0520383542 +28 38 01.245426862 8.88 8.20   6.9   K2+IVeFe-1 723 0

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