The oldest galactic open clusters - New CCD photometry and colour-magnitude diagrams

Paez, E.; Martinez Roger, C.; Arribas, S.; Straniero, O.; Caputo, F.
Bibliographical reference

(IAU, European Regional Astronomy Meeting on New Windows to the Universe, 11th, La Laguna, Spain, July 3-8, 1989) Astrophysics and Space Science (ISSN 0004-640X), vol. 169, no. 1-2, July 1990, p. 41-44.

Advertised on:
7
1990
Number of authors
5
IAC number of authors
0
Citations
3
Refereed citations
3
Description
The paper presents CCD photometry for stars in three fields centered on the old open cluster NGC 188 and in four fields on the intermediate-age cluster NGC 7789, which has been performed with the aim of investigating the HR diagram distribution of the cluster's Main-Sequence (MS) stars. A sufficiently well-defined sequence of subgiant, turn-off, and MS stars have been detected, extending the observed lower MS down to about V = 20 mag.