Astronomy and Astrophysics – Astronomy
Scientific paper
Aug 1995
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1995apj...449..164s&link_type=abstract
Astrophysical Journal v.449, p.164
Astronomy and Astrophysics
Astronomy
24
Galaxies: Magellanic Clouds, Galaxy: Open Clusters And Associations: Individual Ngc Number: Ngc 1850, Stars: Cepheids, Stars: Evolution
Scientific paper
We present the results of a study aimed at identifying variable stars in the rich LMC cluster NGC 1850. V and I band CCD imaging spanning more than 5 years in a 10' x 10' field surrounding the cluster has allowed us to identify more than 30 variable stars, including seven classical Cepheids, one anomalous Cepheid, two RR Lyrae variables, 19 long-period variables (LPVs), one blue eclipsing binary, one possible pair of eclipsing giants, and several peculiar variables. The only likely cluster member is a Cepheid.
Isochrone fitting to the cluster CMD yields an age of 80 Myr if an LMC distance modulus of 18.5 is adopted. A comparison of pulsation and evolution masses for the Cepheids still yields a ratio of evolution to pulsation mass of ˜1.2 for evolution models computed with core overshoot parameter Λ = 0.5, where Λ = 2dovHp ,dov is the distance that convection overshoots beyond the Schwarzschild boundary and Hp is the pressure scale height. An overshoot parameter Λ ˜ 1.0 would be required to bring the evolution and pulsation masses into agreement. One of the Cepheids in the field is a bump Cepheid. A calculation of the bump mass yields a value in reasonable agreement with the pulsation mass. We show that detailed modelling of individual bump Cepheids is capable of providing very tight constraints on the LMC distance modulus. The Cepheid period-luminosity-color relation compared to the theoretical relation yields a LMC distance modulus of 18.60. Finally, arguments are presented which suggest that the LPVs are a mixture of fundamental mode pulsators and small-amplitude overtone pulsators.
Sebo Kim M.
Wood Peter R.
No associations
LandOfFree
Variable Stars in Magellanic Cloud Clusters. II. NGC 1850 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Variable Stars in Magellanic Cloud Clusters. II. NGC 1850, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Variable Stars in Magellanic Cloud Clusters. II. NGC 1850 will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1269125