Photoelectric search for peculiar stars in open clusters. XIV. NGC 1901, NGC 2169, NGC 2343, CR 132, NGC 2423 and NGC 2447.
Abstract
Using the photoelectric Δα-index for detecting chemically peculiar stars with global magnetic fields on the upper main sequence (=CP2 stars) a search was made for 121 stars in six southern open cluster fields. The only existing, however controversial spectroscopic CP2-detection (NGC 2169-12) was confirmed by a strong and variable Δα-value. Pronounced photometric peculiarity was also found for Cr 132a-27, while the other two new photometric CP2-detections (in NGC 2423: ADS 6223 and 11213) are closely above the peculiarity threshold. No CP2-object was found in NGC 1901, NGC 2343 (confirming at a higher precision level the results of Jenkner & Maitzen 1987) and NGC 2447 (where one third of the objects of this programme was measured). Negative Δα-values indicate the possible presence of a Be-star (NGC 2169-15) and a λ Bootis star (NGC 2447-29). There is an indication of a possible intrinsic (=reddening independent) difference in the location of some normality lines (e.g. NGC 2343 as compared to NGC 2169) which may be associated with a difference in chemical composition between both clusters. A number of own V-measurements and b - y-determinations (by transformation from g1 - y) have been obtained for stars with no published values of these quantities. Some typographical errors in the literature are pointed out.
- Publication:
-
Astronomy and Astrophysics Supplement Series
- Pub Date:
- November 1993
- Bibcode:
- 1993A&AS..102....1M
- Keywords:
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- stars: chemically peculiar;
- open clusters: general