2 research outputs found
Simultaneous optical and X-ray observations of flares and rotational modulation on the RS CVn binary HR 1099 (V711 Tau) from the MUSICOS 1998 campaign
We present simultaneous and continuous observations of the H,
H, He {\sc i} D, Na {\sc i} D,D doublet and the Ca
{\sc ii} H & K lines for the RS CVn system HR 1099. The spectroscopic
observations were obtained during the MUSICOS 1998 campaign involving several
observatories and instruments, both echelle and long-slit spectrographs. During
this campaign, HR 1099 was observed almost continuously for more than 8 orbits
of 2\fd8. Two large optical flares were observed, both showing an increase in
the emission of H, Ca {\sc ii} H & K, H and He {\sc i} D
and a strong filling-in of the Na {\sc i} D,D doublet.
{Contemporary photometric observations were carried out with the robotic
telescopes APT-80 of Catania and Phoenix-25 of Fairborn Observatories. Maps of
the distribution of the spotted regions on the photosphere of the binary
components were derived using the Maximum Entropy and Tikhonov photometric
regularization criteria}. Rotational modulation was observed in H and
He {\sc i} D in anti-correlation with the photometric light curves. Both
flares occurred at the same binary phase (0.85), suggesting that these events
took place in the same active region. Simultaneous X-ray observations,
performed by ASM on board RXTE, show several flare-like events, some of which
correlate well with the observed optical flares. Rotational modulation in the
X-ray light curve has been detected with minimum flux when the less active G5 V
star was in front. A possible periodicity in the X-ray flare-like events was
also found.Comment: 20 pages, 12 figures, 8 tables, accepted by A&