A first-overtone RR Lyrae star with cyclic period changes

A. Derekas, L. L. Kiss, A. Udalski, T. R. Bedding, K. Szatmáry

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

A detailed light-curve analysis is presented for a first-overtone RR Lyrae star, MACHO* J050918.712-695015.31, based on MACHO and OGLE-III observations. As a foreground object of the Large Magellanic Cloud, it gives an extraordinary opportunity to study an almost continuous, 12-yr long data set of a relatively bright (V ≈ 15.0 mag) RRc star with rapid period change. Cyclic period modulation is suggested by the O-C method, where the cycle length is about 8 yr. With the available unique data set, we could draw strong limits on other light-curve changes that may be associated with the period modulation. We could exclude both multiple periodicity and amplitude modulation unambiguously. Any theoretical model should reproduce the observed lack of photometric modulations. Simple arguments are also given for possible hydromagnetic effects.

Original languageEnglish
Pages (from-to)821-826
Number of pages6
JournalMonthly Notices of the Royal Astronomical Society
Volume354
Issue number3
DOIs
Publication statusPublished - Nov 1 2004

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massive compact halo objects
harmonics
modulation
stars
light curve
periodicity
Magellanic clouds
magnetohydrodynamics
periodic variations
cycles
analysis
effect
method

Keywords

  • Stars: individual: MACHO* J050918.712-695015.31
  • Stars: variables: other

ASJC Scopus subject areas

  • Space and Planetary Science

Cite this

A first-overtone RR Lyrae star with cyclic period changes. / Derekas, A.; Kiss, L. L.; Udalski, A.; Bedding, T. R.; Szatmáry, K.

In: Monthly Notices of the Royal Astronomical Society, Vol. 354, No. 3, 01.11.2004, p. 821-826.

Research output: Contribution to journalArticle

Derekas, A. ; Kiss, L. L. ; Udalski, A. ; Bedding, T. R. ; Szatmáry, K. / A first-overtone RR Lyrae star with cyclic period changes. In: Monthly Notices of the Royal Astronomical Society. 2004 ; Vol. 354, No. 3. pp. 821-826.
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