V2109 Cygni, a second overtone field RR Lyrae star

L. L. Kiss, B. Csák, J. R. Thomson, J. Vinkó

Research output: Contribution to journalArticle

12 Citations (Scopus)


We present the first (as of February, 1999) U BV and uvby photometric measurements for the short period variable star V2109 Cyg discovered by the Hipparcos satellite and classified as a field RRc variable. We have obtained new times of maxima and the period change has been studied. We determined the fundamental physical parameters using the geometric distance of the star and the most recent synthetic colour grids. The results are: [Fe/H] = -0.9 ± 0.2, M bol = 0.73 ± 0.43 mag, (T eff) = 6800 ± 200 K, logg = 2.7 ± 0.2, R = 4.6 ± 0.9R⊙. Additionally, we took medium resolution (λ/Δλ ≈ 11000) spectra in the red spectral region centered at 6600 Å. A complete radial velocity curve has been determined from 60 spectra. We found no systematic difference between the velocities from Hα and metallic lines indicating a smooth pulsation. The mass of the star is found to be M = 0.5 ± 0.3M⊙ using the photometric logg value and the acceleration curve calculated from the radial velocity data. The finally adopted set of the physical parameters lies in the typical range of RR Lyrae stars, which implies that V2109 Cyg is the shortest period RR Lyrae-type variable. The visual amplitude vs. period and the Fourier amplitude parameter R 21 vs. period diagrams suggest that V2109 Cyg probably pulsates in the second overtone mode. stars: fundamental parameters - stars: individual: V 2109 Cyg - stars: oscillations - stars: variables: RR Lyr.

Original languageEnglish
Pages (from-to)149-155
Number of pages7
JournalAstronomy and Astrophysics
Issue number1
Publication statusPublished - Dec 1 1999

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Fingerprint Dive into the research topics of 'V2109 Cygni, a second overtone field RR Lyrae star'. Together they form a unique fingerprint.

  • Cite this

    Kiss, L. L., Csák, B., Thomson, J. R., & Vinkó, J. (1999). V2109 Cygni, a second overtone field RR Lyrae star. Astronomy and Astrophysics, 345(1), 149-155.