Time-series analysis of long-term photometry of BM Canum Venaticorum
Research output: Contribution to journal › Journal article › Research › peer-review
Long-term photometry is commonly used to monitor chromospheric activity
of late-type stars. We study standard Johnson differential V photometry
of the RS CVn binary BM Canum Venaticorum (BM CVn) spanning over a
quarter of a century. Our main aims are to determine the activity
cycles, the rate of surface differential rotation, and the rotation
period of the active longitudes of BM CVn. The continuous period search
(CPS) algorithm is applied to the photometry. The changes of the mean
and amplitude of the light curves are used to search for activity
cycles. The rotation period changes give an estimate of the rate of
surface differential rotation. The Kuiper method is applied to the
epochs of the primary and secondary minima to search for active
longitudes. The photometry reveals the presence of a stable mean light
curve (MLC) connected to the orbital period
Porb=20.d6252 of this binary. We remove this MLC
from the original V magnitudes, which gives us the corrected
V'magnitudes. These two samples of Vand V'data are analyzed separately
with CPS. The fraction of unreliable CPS models decreases when the MLC
is removed. The same significant activity cycle of approximately 12.5
years is detected in both V and V'samples. The estimate for the surface
differential rotation coefficient, k⩾0.10, is the same for both
samples, but the number of unrealistic period estimates decreases after
removing the MLC. The same active longitude period of
Pal=20.d511 ± 0.d005 is detected
in the V and V' magnitudes. This long-term regularity in the epochs of
primary and secondary minima of the light curves is not caused by the
MLC. On the contrary, the MLC hampers the detection of active
longitudes. The analyzed photometry and numerical results of the
analysis are both published electronically at the CDS via anonymous ftp
to cdsarc.u-strasbg.fr
(130.79.128.5) or via
http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/yyy/Axxx.
Original language | English |
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Journal | Astronomische Nachrichten |
Volume | 338 |
Issue number | 4 |
Pages (from-to) | 453-463 |
ISSN | 0004-6337 |
DOIs | |
Publication status | Published - 1 May 2017 |
- methods: data analysis, stars: activity, stars: binaries, stars: starspots, stars: individual (BM CVn), binaries, starspots, individual (BM CVn)
Research areas
ID: 271766175