Issue |
Astron. Astrophys. Suppl. Ser.
Volume 147, Number 1, November II 2000
|
|
---|---|---|
Page(s) | 99 - 109 | |
DOI | https://doi.org/10.1051/aas:2000294 | |
Published online | 15 November 2000 |
CCD photometric search for peculiar stars in open clusters*
I. NGC 2169, Melotte 105 and NGC 6250
1
Institut für Astronomie der Universität Wien, Türkenschanzstr. 17, A-1180 Wien, Austria
2
Zentraler Informatikdienst der Universität Wien, Universitätsstr. 7, A-1010 Wien, Austria
Send offprint request to: E. Paunzen, e-mail: Ernst.Paunzen@univie.ac.at
Received:
3
April
2000
Accepted:
25
August
2000
The search for chemically peculiar (CP) stars in open clusters
using photoelectric photometry sampling the presence of the
characteristic flux depression feature at 5200 Å via the
-system (Maitzen 1976) has so far delivered data
for objects usually no more distant than 1000 pc from the Sun.
A series of fourteen papers (first: Maitzen & Hensberge 1981;
for the time being last: Maitzen 1993) were devoted to 1240 stars
in 38 open cluster fields.
If one intends to study the presence of CP stars at larger
distances from the Sun, classical photometry has to be replaced
by CCD photometry. We have therefore initialized in 1995 a new
survey in open clusters and the Large Magellanic Cloud using the
CCD technology.
As a first step, we have presented new
-photometry of
22 CP2 stars in the galactic field to prove the capability of
CCD photometry for our aim (Maitzen et al. 1997).
In the first paper of a new series devoted to CCD photometry,
we present data on NGC 2169 (13 stars investigated), Melotte 105 (114 stars),
and NGC 6250 (48 stars). NGC 2169 was used to test our results
with those of classical photometry which yields excellent agreement.
For NGC 6250 we find two new definite CP2 (according
to the definition by Preston 1974) stars (
= 0.065
and 0.026 mag) and two λ Bootis candidates. Twelve objects
with only marginally peculiar
-values for Melotte 105 were
detected.
Additional spectroscopic and photometric evidence is needed to
substantiate their peculiarity.
Key words: stars: chemically peculiar / stars: early-type / techniques: photometric / open clusters and associations: general
© European Southern Observatory (ESO), 2000