A photometric and spectroscopic study of the southern open clusters Pismis 18, Pismis 19, NGC 6005, and NGC 6253

Andrés E. Piatti, Juan J. Clariá, Eduardo Bica, Doug Geisler, Dante Minniti

Research output: Contribution to journalArticlepeer-review

40 Citations (Scopus)

Abstract

CCD observations in the B, V, and I passbands have been used to generate color-magnitude diagrams (CMDs) for the southern open cluster candidates Pismis 18, Pismis 19, and NGC 6005, as well as for the old open cluster NGC 6253. The sample consists of about 1550 stars reaching down to V ∼ 19 mag. From analysis of the CMDs, the physical reality of the three cluster candidates is confirmed and their reddening, distance, and age are derived, as well as those of NGC 6253. In addition, integrated spectra for Pismis 18, Pismis 19, and NGC 6253 covering a range from 3500 to 9200 Å were obtained. The reddening, age, and metallicity of these three clusters were derived from Balmer and Ca II triplet equivalent widths by comparing the observed spectra with those of template clusters. The photometric and spectroscopic results allow us to conclude that Pismis 18, Pismis 19, and NGC 6005 are intermediate-age (t ≈ 1 Gyr), genuine open clusters, while NGC 6253 has an age t ≈ 5 Gyr. All these clusters are located approximately toward the Galactic center, between 1.5 and 2.7 kpc from the Sun. Their metallicities range over values that are typical of moderately metal-poor to moderately metal-rich open clusters.

Original languageEnglish
Pages (from-to)801-812
Number of pages12
JournalAstronomical Journal
Volume116
Issue number2
DOIs
Publication statusPublished - Aug 1998

Keywords

  • Galaxies
  • Individual (Pismis 18, Pismis 19, NGC 6005, NGC 6253)
  • Star clusters - open clusters and associations

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Fingerprint

Dive into the research topics of 'A photometric and spectroscopic study of the southern open clusters Pismis 18, Pismis 19, NGC 6005, and NGC 6253'. Together they form a unique fingerprint.

Cite this