New variable stars discovered in the fields of three Galactic open clusters using the VVV survey

T. Palma, D. Minniti, I. Dékány, J. J. Clariá, J. Alonso-García, L. V. Gramajo, S. Ramírez Alegría, C. Bonatto

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)


This project is a massive near-infrared (NIR) search for variable stars in highly reddened and obscured open cluster (OC) fields projected on regions of the Galactic bulge and disk. The search is performed using photometric NIR data in the J-, H- and Ks- bands obtained from the Vista Variables in the Vía Láctea (VVV) Survey. We performed in each cluster field a variability search using Stetson's variability statistics to select the variable candidates. Later, those candidates were subjected to a frequency analysis using the Generalized Lomb-Scargle and the Phase Dispersion Minimization algorithms. The number of independent observations range between 63 and 73. The newly discovered variables in this study, 157 in total in three different known OCs, are classified based on their light curve shapes, periods, amplitudes and their location in the corresponding color-magnitude (J−Ks,Ks) and color-color (H−Ks,J−H) diagrams. We found 5 possible Cepheid stars which, based on the period-luminosity relation, are very likely type II Cepheids located behind the bulge. Among the newly discovered variables, there are eclipsing binaries, δ Scuti, as well as background RR Lyrae stars. Using the new version of the Wilson & Devinney code as well as the “Physics Of Eclipsing Binaries” (PHOEBE) code, we analyzed some of the best eclipsing binaries we discovered. Our results show that these studied systems turn out to be ranging from detached to double-contact binaries, with low eccentricities and high inclinations of approximately 80°. Their surface temperatures range between 3500 K and 8000 K.

Original languageEnglish
Pages (from-to)50-62
Number of pages13
JournalNew Astronomy
Publication statusPublished - 1 Nov 2016


  • ASCC 90
  • Antalova 1
  • ESO 393-15 – stars
  • Galaxy
  • General
  • Individual
  • Stellar content – open clusters and associations
  • Variables

ASJC Scopus subject areas

  • Instrumentation
  • Astronomy and Astrophysics
  • Space and Planetary Science


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