Issue |
Astron. Astrophys. Suppl. Ser.
Volume 146, Number 3, November I 2000
|
|
---|---|---|
Page(s) | 377 - 384 | |
DOI | https://doi.org/10.1051/aas:2000276 | |
Published online | 15 November 2000 |
Long-time behavior of orbital periods of some Algol-type eclipsing binaries*
1
Yunnan Observatory, Chinese Academy of Sciences, P.O. Box 110, 650011 Kunming, PR China e-mail: qsb@netease.com
2
National Astronomical Observatories, Chinese Academy of Science (NAOCAS), PR China
3
United Laboratory of Optical Astronomy, Chinese Academy of Science (ULOAC), PR China
Send offprint request to: Qian Shengbang
Received:
2
May
2000
Accepted:
19
July
2000
Orbital period variations of six semi-detached binaries,
UW Cyg, RX Hya, AK Ser, AC Tau, UW Vir and VV Vul, are
presented based on the analysis of their O–C observations.
For AK Ser and VV Vul, their orbital periods may show secular
increase at rates of and
days/year. For UW Cyg, its orbital period
is revised, and the O–C curve shows a cyclic variation with
a period of 49.2 years and an amplitude of
.
For the other three systems, RX Hya, AC Tau and UW Vir, the
changes in their orbital periods appear more complex but their
O–C curves can be represented by periodic variations (with
periods of 54.3, 29.8 and 45.9 years) superimposed on
upward parabolic segments. The components of upward curving
parabolic variations in RX Hya, AC Tau and UW Vir indicate secular
period increase with rates of
,
and
days/year
respectively. The secular period increase in the
five systems, RX Hya, AK Ser, AC Tau, UW Vir and VV Vul, can be
explained by mass transfer from the less to the massive
components, which is consistent with their semi-detached
configurations. The periodic changes of the orbital periods
in UW Cyg, RX Hya, AC Tau, UW Vir may be caused by the
light-time effects due to the existence of the third bodies.
Key words: stars: individuals: UW Cyg, RX Hya, AK Ser, AC Tau, UW Vir and VV Vul
© European Southern Observatory (ESO), 2000