The Hα stellar and interstellar emission in the open cluster NGC 6910

¹ Astronomický ústav, Akademie věd České republiky, Fričova 298, 251 65 Ondřejov, Czech Republic e-mail: kubat@sunstel.asu.cas.cz
² Instytut Astronomiczny Uniwersytetu Wrocławskiego, ul. Kopernika 11, 51-622 Wrocław, Poland

Received: 26 January 2007
Accepted: 1 June 2007

Abstract

Aims.We verify the nature of emission-line stars in the field of the open cluster NGC 6910.

Methods.Spectroscopy in the Hα region was obtained. Raw CCD frames of spectra of all stars fainter than V = 9 mag observed by us are significantly affected by nebular emission originating in the surrounding region IC 1318. After careful data reduction and subtraction of the nebular radiation we succeeded in obtaining reliable stellar spectra.

Results.We confirm that the star NGC 6910 37 is a Be star, and we have corrected the classification of V1973 Cyg from an Ae star to a normal A type star. Since the diffuse interstellar bands do not appear in the spectrum of this star while being present in the other stars we observed, we confirm that V1973 Cyg is a foreground object with respect to IC 1318 and NGC 6910. We also find that the Hα line in HD 194279 has a P Cygni profile and the Hα line profile is variable in HD 229196.