2013A&A...559A.108M


Query : 2013A&A...559A.108M

2013A&A...559A.108M - Astronomy and Astrophysics, volume 559A, 108-108 (2013/11-1)

Pulsating stars in NGC 6231. Frequency analysis and photometric mode identification near the main-sequence.

MEINGAST S., HANDLER G. and SHOBBROOK R.R.

Abstract (from CDS):

We used Johnson UBV photometric CCD observations to identify pulsating and other variable stars in the young open cluster NGC 6231. The multi-colour information was used to classify pulsating variables, perform frequency analysis, and, where possible, to compare observed to theoretical amplitude ratios for mode identification. The CCD data were used to investigate a total of 473 stars in the field. The data reduction was performed with standard IRAF tools, while the extraction of light curves was done with combined aperture and point-spread-function photometry routines delivered with the DAOPHOT package. Differential light curves were obtained by identifying a set of suitable comparison stars and the frequency analysis was then conducted on the basis of Fourier methods. Our classification of pulsating stars was based on the time scales and amplitudes of the variability with respect to the different filters and stellar parameters as calculated from published Stroemgren and Geneva photometry. Attempts to set constraints on the pulsation mode were performed for stars with sufficiently high amplitude based on the significant dependence of amplitudes on wavelength. We identified 32 variable stars in the field of the cluster, of which 21 are confirmed members of NGC 6231 and 12 are newly detected variable stars. Ten stars were classified as slowly pulsating B (SPB) stars in NGC 6231, of which seven are new discoveries. We also analysed six previously reported β Cephei variables in more detail. One of them may be a hybrid β Cephei/SPB pulsator. In addition, we also investigated five previously suspected pulsators of this group that we cannot convincingly confirm owing to their small pulsation amplitudes. The remaining 11 variable stars are either not members of NGC 6231 or the membership status is questionable. Among them are three previously known δ Scuti stars, two newly detected pulsators of this class, one new and two already known eclipsing binaries, one new SPB variable, one possible pre-main-sequence pulsator, and another new variable star for which we cannot present a classification. With more than 20 main-sequence pulsators of spectral type B, NGC 6231 becomes the open cluster with the largest population of such pulsating stars known.

Abstract Copyright:

Journal keyword(s): stars: oscillations - stars: variables: general - methods: observational - techniques: photometric - methods: data analysis

Simbad objects: 33

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Number of rows : 33
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 HD 326327 Be* 16 53 39.0780958656 -41 47 48.021660096 9.372 9.969 9.729 10.03 9.312 B1.5Ve 51 0
2 2MASS J16534698-4148549 Y*? 16 53 46.9871839944 -41 48 54.948359880 12.400 12.621 12.375 12.60 11.962 B6-8V 11 0
3 2MASS J16535205-4148541 Y*? 16 53 52.0599810384 -41 48 54.086756796 11.886 12.230 12.034 12.20 11.619 Ap 12 0
4 V* V945 Sco bC* 16 53 54.5203569984 -41 52 14.960561412 9.090 9.745 9.575 9.618 9.260 B1V 41 0
5 V* V1032 Sco bC* 16 53 58.6055666592 -41 48 41.790648132 9.327 9.920 9.767 9.811 9.445 B2V 39 0
6 NGC 6231 249 Pu* 16 53 59.3149479480 -41 53 04.040266236 11.810 12.132 11.876 12.11 11.504 B4-5V 14 0
7 2MASS J16535997-4146263 Y*? 16 53 59.9749277160 -41 46 26.332486608 12.536 12.727 12.430 12.72 12.011 B 12 0
8 V* V946 Sco bC* 16 54 01.7631666120 -41 51 11.868345252 9.890 10.471 10.281 10.327 9.927 B2IV-V 44 0
9 V* V1199 Sco dS* 16 54 01.8665401536 -41 53 23.809520688 15.089 14.655 13.974 14.24 13.124 ~ 13 0
10 2MASS J16540315-4151492 Y*? 16 54 03.1543694544 -41 51 49.267424952 10.675 11.144 10.907 11.9 10.528 B2-3V 24 0
11 CD-41 11032 SB* 16 54 06.9496123464 -41 49 23.360333088 8.93 9.60 9.512 10.81 9.256 B0.5V 37 0
12 NGC 6231 OpC 16 54 08.51 -41 49 36.0   2.83 2.6     ~ 515 0
13 NGC 6231 209 Y*? 16 54 10.7255921880 -41 47 47.372416692 10.307 10.795 10.599 10.62 10.265 B2IV-V 28 0
14 V* V1202 Sco gD* 16 54 12.9361182240 -41 52 28.864465752 16.252 15.772 14.618 14.52 13.223 ~ 9 0
15 CPD-41 7734 Pu* 16 54 14.2460503200 -41 55 01.326705420 10.103 10.616 10.331 10.25 9.801 B0Vn 26 0
16 NGC 6231 200 * 16 54 14.8505354784 -41 46 58.345311720 13.349 13.067 12.602 12.70 12.011 ~ 4 0
17 V* V1205 Sco dS* 16 54 15.7377001608 -41 51 39.861550332 14.548 13.87 13.22 13.38 12.671 A5III 12 0
18 CD-41 7736 Pu* 16 54 15.7425941640 -41 49 32.321424612 9.859 10.400 10.174 10.14 9.780 B1Vn 31 0
19 CPD-41 7737 Pu* 16 54 16.3028817696 -41 50 26.660630976 10.456 10.955 10.745 10.71 10.387 B1V 21 0
20 2MASS J16541680-4145083 Y*? 16 54 16.8013206864 -41 45 08.349698880 11.732 11.847 11.573   11.118 B8-9V 17 0
21 2MASS J16541793-4148013 Y*? 16 54 17.9338413600 -41 48 01.303610616 10.799 11.257 11.059 11.12 10.735 B2IVn 21 0
22 2MASS J16541813-4150164 Y*? 16 54 18.1360278600 -41 50 16.435116096 13.332 13.392 13.062 13.26 12.553 B9V 12 0
23 V* V964 Sco bC* 16 54 18.3200772432 -41 51 35.651104416 9.126 9.776 9.603 9.61 9.290 B0.5V 57 0
24 V* V1207 Sco Pu* 16 54 20.6163048120 -41 49 28.631620668 11.062 11.455 11.198 11.23 10.774 B1Vn: 12 0
25 V* V1208 Sco EB* 16 54 21.3090092232 -41 51 41.766233904 9.293 9.91 9.708 9.96 9.344 B0-2V 44 0
26 2MASS J16542169-4149544 Y*? 16 54 21.6930463104 -41 49 54.394363704 11.825 12.011 11.719 11.81 11.302 B6Vn 13 0
27 NGC 6231 230 * 16 54 26.1062682696 -41 51 31.108244580 13.009 12.893 12.462 12.58 11.823 ~ 10 0
28 V* V1212 Sco dS* 16 54 31.2204545496 -41 55 28.604944992 10.728 10.401 9.945 9.86 9.347 F0III 27 0
29 V* V947 Sco bC* 16 54 36.0500878224 -41 53 38.119259292 9.45 10.06 9.78 10.06   B1V 50 0
30 2MASS J16544238-4147164 Y*? 16 54 42.3750696960 -41 47 16.480964364 15.593 15.053 14.426   13.467 ~ 5 0
31 V* V920 Sco bC* 16 54 43.1657949576 -41 49 35.456774916 9.153 9.795 9.601 9.95 9.256 B1V 62 0
32 NGC 6231 126 * 16 54 48.7493678832 -41 52 30.712565064 12.856 12.602 12.239   11.771 B1V 7 0
33 UCAC3 97-240594 * 16 55 18.0862157736 -41 46 24.129254100       13.73   ~ 1 0

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2022.11.28-13:20:53

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