J/A+A/533/A70 New β Cep stars in NGC 637 (Handler+, 2011)
New beta Cephei stars in the young open cluster NGC 637.
Handler G., Meingast S.
<Astron. Astrophys. 533, A70 (2011)>
=2011A&A...533A..70H 2011A&A...533A..70H
ADC_Keywords: Clusters, open ; Stars, early-type ; Photometry, CCD
Keywords: stars: early-type - open clusters and associations: general -
techniques: photometric - stars: oscillations - asteroseismology
Abstract:
Studying stellar pulsations in open clusters offers the possibility of
performing ensemble asteroseismology. The reasonable assumption that
the cluster members have the same age, distance, and overall
metallicity aids in the seismic modelling process and tightly
constrains it. Therefore it is important to identify open clusters
with many pulsators. New pulsating stars of the beta Cephei type were
searched for among the members of the open cluster NGC 637. Thirty-one
hours of time-resolved V filter CCD photometry were obtained. The
measurements confirmed two previously known variables, and revealed
three new beta Cephei stars and one more candidate. All four pulsators
have sufficiently large amplitudes for easy mode identification and
are multiperiodic. With four certain pulsating members, NGC 637 is now
among the open clusters that are richest in beta Cephei stars. It is
thus an excellent target for ensemble asteroseismology, and to examine
the differences between pulsating and apparently constant stars in the
beta Cephei domain.
Description:
The time series photometry for all variable cluster members is
presented.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
stars.dat 76 9 Stars list
v001.dat 18 597 Light curves of NGC 637 WEBDA 1
v003.dat 18 599 Light curves of NGC 637 WEBDA 3
v004.dat 18 602 Light curves of NGC 637 WEBDA 4
v006.dat 18 599 Light curves of NGC 637 WEBDA 6
v007.dat 18 600 Light curves of NGC 637 WEBDA 7
v013.dat 18 404 Light curves of NGC 637 WEBDA 13
v033.dat 18 404 Light curves of NGC 637 WEBDA 33
v068.dat 18 601 Light curves of NGC 637 WEBDA 68
v138.dat 18 601 Light curves of NGC 637 WEBDA 138
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Byte-by-byte Description of file: stars.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Star Star number
5- 6 I2 h RAh Right ascension (J2000)
8- 9 I2 min RAm Right ascension (J2000)
11- 15 F5.2 s RAs Right ascension (J2000)
17 A1 --- DE- Declination sign (J2000)
18- 19 I2 deg DEd Declination (J2000)
21- 22 I2 arcmin DEm Declination (J2000)
24- 28 F5.2 arcsec DEs Declination (J2000)
30- 37 A8 --- FileName Name of the file with the light curve
39- 56 A18 --- SName Simbad name
61- 67 F7.5 d-1 f1 ? Main (dominant) frequency
70- 76 F7.5 d-1 f2 ? Secondary frequency
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Byte-by-byte Description of file: v*.dat
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Bytes Format Units Label Explanations
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2- 10 F9.6 d Date Heliocentric Julian Date of mid exposure,
HJD-2455560
12- 18 F7.4 mag Vmag Relative V magnitude
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Acknowledgements:
Gerald Handler, gerald(at)gatekeeper.camk.edu.pl
(End) Patricia Vannier [CDS] 01-Aug-2011