Abstract
We report the results of CCD V and R photometry of the RR Lyrae stars in M2. The periodicities of most variables are revised and new ephemerides are calculated. Light-curve decomposition of the RR Lyrae stars was carried out and the corresponding mean physical parameters [Fe/H] = -1.47, T ef{ = 6276 K, log L = 1.63 L ⊙ and M V = 0.71 from nine RRab and [Fe/H] = -1.61, M = 0.54 M ⊙, T eff- = 7215 K, log L = 1.74 L ⊙ and M V = 0.71 from two RRc stars were calculated. A comparison of the radii obtained from the above luminosity and temperature with predicted radii from non-linear convective models is discussed. The estimated mean distance to the cluster is 10.49 ± 0.15 kpc. These results place M2 correctly in the general globular cluster sequences for Oosterhoff type, mass, luminosity and temperature, all as a function of the metallicity. Mean relationships for M, log L/L ⊙, T eff and M V as a function of [Fe/H] for a family of globular clusters are offered. These trends are consistent with evolutionary and structural notions on the horizontal branch. Eight new variables are reported.
| Original language | English |
|---|---|
| Pages (from-to) | 69-80 |
| Number of pages | 12 |
| Journal | Monthly Notices of the Royal Astronomical Society |
| Volume | 372 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - 1 Oct 2006 |
| Externally published | Yes |
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Keywords
- Globular clusters: individual: M2
- Stars: horizontal branch
- Stars: Population II
- Stars: variables: other
ASJC Scopus subject areas
- Space and Planetary Science
Cite this
CCD photometry of the globular cluster M2 : RR Lyrae physical parameters and new variables. / Lázaro, C.; Arellano Ferro, A.; Arévalo, M. J.; Bramich, D. M.; Giridhar, S.; Poretti, E.
In: Monthly Notices of the Royal Astronomical Society, Vol. 372, No. 1, 01.10.2006, p. 69-80.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - CCD photometry of the globular cluster M2
T2 - RR Lyrae physical parameters and new variables
AU - Lázaro, C.
AU - Arellano Ferro, A.
AU - Arévalo, M. J.
AU - Bramich, D. M.
AU - Giridhar, S.
AU - Poretti, E.
PY - 2006/10/1
Y1 - 2006/10/1
N2 - We report the results of CCD V and R photometry of the RR Lyrae stars in M2. The periodicities of most variables are revised and new ephemerides are calculated. Light-curve decomposition of the RR Lyrae stars was carried out and the corresponding mean physical parameters [Fe/H] = -1.47, T ef{ = 6276 K, log L = 1.63 L ⊙ and M V = 0.71 from nine RRab and [Fe/H] = -1.61, M = 0.54 M ⊙, T eff- = 7215 K, log L = 1.74 L ⊙ and M V = 0.71 from two RRc stars were calculated. A comparison of the radii obtained from the above luminosity and temperature with predicted radii from non-linear convective models is discussed. The estimated mean distance to the cluster is 10.49 ± 0.15 kpc. These results place M2 correctly in the general globular cluster sequences for Oosterhoff type, mass, luminosity and temperature, all as a function of the metallicity. Mean relationships for M, log L/L ⊙, T eff and M V as a function of [Fe/H] for a family of globular clusters are offered. These trends are consistent with evolutionary and structural notions on the horizontal branch. Eight new variables are reported.
AB - We report the results of CCD V and R photometry of the RR Lyrae stars in M2. The periodicities of most variables are revised and new ephemerides are calculated. Light-curve decomposition of the RR Lyrae stars was carried out and the corresponding mean physical parameters [Fe/H] = -1.47, T ef{ = 6276 K, log L = 1.63 L ⊙ and M V = 0.71 from nine RRab and [Fe/H] = -1.61, M = 0.54 M ⊙, T eff- = 7215 K, log L = 1.74 L ⊙ and M V = 0.71 from two RRc stars were calculated. A comparison of the radii obtained from the above luminosity and temperature with predicted radii from non-linear convective models is discussed. The estimated mean distance to the cluster is 10.49 ± 0.15 kpc. These results place M2 correctly in the general globular cluster sequences for Oosterhoff type, mass, luminosity and temperature, all as a function of the metallicity. Mean relationships for M, log L/L ⊙, T eff and M V as a function of [Fe/H] for a family of globular clusters are offered. These trends are consistent with evolutionary and structural notions on the horizontal branch. Eight new variables are reported.
KW - Globular clusters: individual: M2
KW - Stars: horizontal branch
KW - Stars: Population II
KW - Stars: variables: other
UR - http://www.scopus.com/inward/record.url?scp=33749178720&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33749178720&partnerID=8YFLogxK
U2 - 10.1111/j.1365-2966.2006.10742.x
DO - 10.1111/j.1365-2966.2006.10742.x
M3 - Article
AN - SCOPUS:33749178720
VL - 372
SP - 69
EP - 80
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
SN - 0035-8711
IS - 1
ER -