Issue |
A&A
Volume 379, Number 3, December I 2001
|
|
---|---|---|
Page(s) | 878 - 883 | |
Section | Interstellar and circumstellar matter | |
DOI | https://doi.org/10.1051/0004-6361:20011357 | |
Published online | 15 December 2001 |
The light and period changes of RT Andromedae
Çanakkale Onsekiz Mart University, Faculty of Arts and Sciences, Department of Physics, 17100 Çanakkale, Turkey
Corresponding author: A. Erdem, aerdem@bornova.ege.edu.tr
Received:
11
June
2001
Accepted:
5
September
2001
The nature of the long-term orbital period variation and the light
level variation of RT And was studied based on all available
photometric observations. The (O-C) diagram formed by all
available times of eclipse minima could be either of a
quasi-sinusoidal form superimposed on a parabolic form, or a long
period sinusoidal form. The quasi-sinusoidal form with an
amplitude of ~0.002 days and a period of ~65 years could
be due to a cyclic magnetic activity modulation on the orbital
period of the system. Applegate's theory (Applegate 1992), in
this case, predicts an ~3 kG mean subsurface magnetic field
for the primary component of the system. The parabolic form
corresponds to a secular period decrease of about caused by mass loss from the system, and
the long-period sinusoidal form with an amplitude of ~0.02 days
and a period of ~105 years corresponds to a secular period
change caused by the light-time effect due to an unseen third star
in the system. It was estimated that the unseen third star should
be a low mass (lower than
) and faint
(
fainter than the system RT And) star, whose detection
is almost impossible. Future data will add information on the
nature of the secular (O-C) variation. Secular light level
variation of the system was found to be irregular and no
correlation was detected with the orbital period variation.
Key words: stars: binaries: eclipsing / stars: individual: RT And
© ESO, 2001
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