J/MNRAS/357/345 Pulsating pre-main-sequence stars in NGC6383 (Zintz+, 2005)
Search for pulsating pre-main-sequence stars in NGC 6383.
Zwintz K., Marconi M., Reegen P., Weiss W.W.
<Mon. Not. R. Astron. Soc., 357, 345-353 (2005)>
=2005MNRAS.357..345Z 2005MNRAS.357..345Z
ADC_Keywords: Stars, pre-main sequence ; Photometry, UBV ; Photometry, CCD
Keywords: techniques: photometric - stars: pre-main-sequence - delta Scuti -
open clusters and associations: individual: NGC 6383
Abstract:
A search for pulsating pre-main-sequence (PMS) stars was performed in
the young open cluster NGC 6383 using CCD time-series photometry in
Johnson B and V filters. With an age of only ∼1.7Myr all cluster
members later than spectral type A0 have not reached the ZAMS yet,
hence being ideal candidates for investigating PMS pulsation among A-
and F-type stars. In total 286 stars have been analysed using
classical Fourier techniques. From about a dozen stars within the
boundaries of the classical instability strip, two stars were found to
pulsate: NGC 6383 #170, with five frequencies simultaneously, and NGC
6383 #198, with a single frequency. In addition, NGC 6383 #152 is a
suspected PMS variable star, but our data remain inconclusive. Linear,
non-adiabatic models assuming PMS evolutionary phase and purely radial
pulsation were calculated for the two new PMS pulsators. NGC 6383 #170
appears to pulsate radially in third and fifth overtones, while the
other three frequencies seem to be of non-radial nature. NGC 6383 #198
pulsates mono-periodically, most probably in the third radial overtone.
Magnitudes and BV colours were available in the literature for only
one third of all stars and we used them for calibrating the remaining.
Description:
CCD photometric time-series in Johnson B and V filters were obtained
with the 0.9-m telescope at the Cerro Tololo Interamerican Observatory
(CTIO), Chile, from 2001 August 11 to 2001 August 24 using the
2084x2046 SITe CCD chip, which provides a field of view (FOV) of
∼13x13arcmin2. In total, 53.25h photometry could be acquired within
eight clear nights.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 55 286 Photometric data for all observed stars
(cluster membership is assumed)
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Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- ZMR Sequential number, Cl* NGC 6383 ZMR NNN in Simbad
5- 10 A6 --- OName Other names in the literature (1)
13- 19 F7.2 pix Xpos X position on the CCD
21- 27 F7.2 pix Ypos Y position on the CCD
29- 34 F6.3 mag Vmag Johnson V magnitude
36- 41 F6.3 mag B-V Johnson B-V colour index
43- 48 F6.3 mag VMAG Absolute V magnitude (2)
50- 55 F6.3 mag (B-V)0 Dereddened Johnson B-V colour index (2)
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Note (1): Cross-identifications as follows:
EV NNN: Evans et al., 1978MNRAS.184..661L 1978MNRAS.184..661L, NGC 6383 NNN in Simbad
F NN: Fitzgerald et al., 1978MNRAS.182..607F 1978MNRAS.182..607F,
Cl* NGC 6383 FJL NN in Simbad
T NNN: The, 1965CoBos..32.....T 1965CoBos..32.....T, NGC 6383 NN in Simbad
Note (2): VMAG and (B-V)0 were derived using E(B-V)=0.33mag and
V-VMAG=11.9mag (Fitzgerald et al., 1978MNRAS.182..607F 1978MNRAS.182..607F).
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 07-Feb-2006