NGC 2516 X-ray sources

Altogether 64 X-ray sources were detected showing strong concentration towards the optical cluster centre. This suggests that most of the sources are actually associated with NGC 2516. 42 of these sources could be identified with optical stars in the field of the cluster; after correction for a mean offset between optical and nominal ROSAT positions of about 13", optical star and X-ray source positions are found to agree, on the average, within about 9", while maximum observed positional differences amount to 27".

X-ray sources identified with optical cluster stars include HR 3147 (=HD 66194; B2.5IVe), the visually brightest B star in the cluster, three close visual late B-type binaries (h 4027 A,B, h 4031 A,B, and I 1104 A,B) with projected separations ranging between about 4x10^16^cm and 6x10^16^cm, as well as several (six) chemically peculiar Bp/Ap(Si) and Ap(SrCrEu) stars.