J/A+A/590/A11 BVRI light curves of V374 Peg (Vida+, 2016)
Investigating magnetic activity in very stable stellar magnetic fields.
Long-term photometric and spectroscopic study of the fully convective M4 dwarf
V374 Pegasi.
Vida K., Kriskovics L., Olah K., Leitzinger M., Odert P. Kovari Zs.,
Korhonen H., Greimel R., Robb R., Csak B., Kovacs B.
<Astron. Astrophys. 590, A11 (2016)>
=2016A&A...590A..11V 2016A&A...590A..11V (SIMBAD/NED BibCode)
ADC_Keywords: Stars, dwarfs ; Magnetic fields ; Photometry, CCD
Keywords: stars: activity - stars: flare - stars: individual: V374 Peg -
stars: late-type - stars: low-mass - starspots
Abstract:
The ultrafast-rotating (Prot∼0.44d) fully convective single M4 dwarf
V374 Peg is a well-known laboratory for studying intense stellar
activity in a stable magnetic topology. As an observable proxy for the
stellar magnetic field, we study the stability of the light curve,
hence the spot configuration. We also measure the occurrence rate of
flares and coronal mass ejections (CMEs). We have analysed
spectroscopic observations, BV(RI)C photometry covering 5yrs, and
additional RC photometry that expands the temporal base over 16yr. The
light curve suggests an almost rigid-body rotation and a spot
configuration that is stable over about 16 yrs, confirming the
previous indications of a very stable magnetic field. We observed
small changes on a nightly timescale and frequent flaring, including a
possible sympathetic flare. The strongest flares seem to be more
concentrated around the phase where the light curve indicates a
smaller active region. Spectral data suggest a complex CME with
falling-back and re-ejected material with a maximal projected velocity
of ∼675km/s. We observed a CME rate that is much lower than expected
from extrapolations of the solar flare-CME relation to active stars.
Description:
Differential BV(RI)_C photometry of V374 Peg, obtained by the 1m RCC
telescope of the Konkoly Observatory at Piszkesteto (comparison star:
GSC 02215-01602)
Objects:
----------------------------------------------------
RA (2000) DE Designation(s)
----------------------------------------------------
22 01 13.13 +28 18 24.9 V374 Peg = HIP 108706
----------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
bvri.dat 41 7257 Differential BV(RI)_C photometry of V374 Pegasi
--------------------------------------------------------------------------------
Byte-by-byte Description of file: bvri.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 F13.5 d HJD Heliocentric Julian date
15- 20 F6.3 mag dBmag Differential Johnson B magnitude
22- 27 F6.3 mag dVmag Differential Johnson V magnitude
29- 34 F6.3 mag dRcmag Differential Cousins R magnitude
36- 41 F6.3 mag dIcmag Differential Cousins I magnitude
--------------------------------------------------------------------------------
Acknowledgements:
Krisztian Vida, vidakris(at)konkoly.hu
(End) Patricia Vannier [CDS] 03-Mar-2016