1998A&A...332..102P


Query : 1998A&A...332..102P

1998A&A...332..102P - Astronomy and Astrophysics, volume 332, 102-110 (1998/4-1)

Period changes in both modes of RRd stars in M15.

PAPARO M., SAAD S.M., SZEIDL B., KOLLATH Z., ABU ELAZM M.S. and SHARAF M.A.

Abstract (from CDS):

A new approach of the phase or O-C diagram is presented. The Fourier phase diagram method combines the advantages of both the phase diagram and Fourier technique. The method is applied for 13 RRd stars in the metal poor Oo II type globular cluster, M15. Previously published periods are corrected up to 6 digits. The precise periods allowed us to get period changes with higher accuracy. Period changes were obtained not only for the first overtone but at the first time for the lower amplitude fundamental mode, too. The period change rate of the fundamental mode is significantly larger for each star than that of the first overtone. The P1/P0 ratio is increasing for most of the stars. Each period change rate is negative for the fundamental mode (except v51). For the first overtone both positive (5) and negative (6) period change rates were obtained. The most striking result is the period change behaviour of different sign for the fundamental and first overtone modes. The most remarkable case is v53 with β=- 0.31±0.06day/Myr for the fundamental mode and β=+0.14±0.01day/Myr for the first overtone. This result suggests that caution is needed in connecting the sign of the period change rate and the direction of the stars's evolution in the HR diagram. Observational comparison is given for RRab and RRc stars and the fundamental and first overtone modes of RRd in M15.

Abstract Copyright:

Journal keyword(s): Galaxy: globular clusters: individual: M15 - stars: oscillations - stars: variables: RR Lyr - methods: data analysis

Simbad objects: 15

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Number of rows : 15
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 NGC 7078 102 RR* 21 29 47.03 +12 09 58.0   16.23 15.00     ~ 26 0
2 Cl* NGC 7078 SAW V31 RR* 21 29 50.46 +12 14 06.5   16.23 15.86     ~ 18 0
3 NGC 7078 210 RR* 21 29 52.0268326957 +12 08 11.609604515   16.14 15.80     ~ 27 0
4 NGC 7078 227 RR* 21 29 52.3719253668 +12 09 52.199502748   16.28 16.7     ~ 18 0
5 Cl* NGC 7078 SAW V61 RR? 21 29 53.7049427697 +12 09 21.077840840   16.19 16.5     ~ 9 0
6 Cl* NGC 7078 SAW V101 RR* 21 29 53.977720713 +12 19 11.63569481   16.18 15.84     ~ 6 0
7 Cl* NGC 7078 SAW V58 * 21 29 54.46 +12 10 10.6   16.25 15.89     ~ 8 0
8 M 15 GlC 21 29 58.33 +12 10 01.2   3       ~ 2986 0
9 Cl* NGC 7078 SAW V51 RR* 21 29 58.67 +12 11 34.4   16.19 15.85     ~ 13 0
10 NGC 7078 612 RR* 21 29 58.9668178750 +12 11 31.014077857   16.16 15.82     ~ 17 0
11 NGC 7078 659 RR* 21 29 59.6968714906 +12 07 58.328399160   16.20 15.85     ~ 19 0
12 Cl* NGC 7078 SAW V26 RR* 21 29 59.6971505763 +12 15 34.578877104   16.25 15.72     ~ 16 0
13 NGC 7078 835 RR* 21 30 02.5860299238 +12 09 08.020941851   16.13 16.4     ~ 11 0
14 NGC 7078 901 RR* 21 30 03.9236076987 +12 11 53.275721758   16.22 15.84     ~ 22 0
15 Cl* NGC 7078 SAW V96 RR* 21 30 09.40 +12 13 38.1   16.26 15.91     ~ 9 0

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2021.11.30-01:09:42

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