Astron. Astrophys. 339, 423-430 (1998)

Red giants in open clusters

VIII. NGC 752 ^*, ^**

J.-C. Mermilliod ¹, R.D. Mathieu ^{2, 3}, D.W. Latham ³ and M. Mayor <sup>4

1</sup> Institut d'Astronomie de l'Université de Lausanne, CH-1290 Chavannes-des-Bois, Switzerland
² Department of Astronomy, University of Wisconsin, Madison WI 53706, USA
³ Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA
⁴ Observatoire de Genève, CH-1290 Sauverny, Switzerland

Received 2 June 1998 / Accepted 31 August 1998

Abstract

The results of an 18-year radial-velocity survey of 30 red giants in the field of the open cluster NGC 752 are presented. The membership of 15 stars is confirmed. Four spectroscopic binaries have been discovered among the members and three orbits have been determined for H75, 110 and 208, with periods of 3321, 127 and 5276 days respectively. The binary frequency (27%) is normal. A search for additional members in a wide surrounding area () yielded two possible new members: both are clump red giant candidates. The red giant distribution in the colour-magnitude diagram is somewhat unusual, with a clump containing 8 stars and a second, fainter feature extending to the blue, defined by 3 or 4 stars, which is not accounted for by theoretical isochrones.

Key words: techniques: radial velocities binaries: spectroscopic Hertzsprung-Russel (HR) diagram open clusters and associations: individual: NGC 2354

* Based on observations collected at the Haute-Provence Observatory (France)
** Tables 4a & 4b are available only in electronic form at CDS by ftp at 130.79.128.5 (ftp://cdsarc.u-strasbg.fr/pub/cats/J/A+A/339/423) or on the Web at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/339/423

Send offprint requests to: J.-C. Mermilliod

© European Southern Observatory (ESO) 1998

Online publication: October 21, 1998

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