NGC 1261: A time-series emph{VI} study of its variable stars. (arXiv:1908.04808v1 [astro-ph.SR])

NGC 1261: A time-series emph{VI} study of its variable stars. (arXiv:1908.04808v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Ferro_A/0/1/0/all/0/1">A. Arellano Ferro</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fierro_I/0/1/0/all/0/1">I.H. Bustos Fierro</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Calderon_J/0/1/0/all/0/1">J.H. Calder&#xf3;n</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ahumada_J/0/1/0/all/0/1">J.A. Ahumada</a>

Time-series emph{VI} CCD photometry of the globular cluster NGC 1261 is
employed to study its variable star population. A membership analysis of most
variables based on Gaia~DR2 proper motions and colours, was performed prior to
the estimation of the mean cluster distance and metallicity. For the member RR
Lyrae, their light curves were Fourier decomposed to calculate their individual
values of distance, [Fe/H], radius and mass. The $I$-band P-L for RR Lyrae
stars was also employed. Our best estimates of the metallicity and distance of
this Oo I cluster are [Fe/H]$_{rm ZW}$=$-1.42 pm 0.05$ dex and $d=17.2 pm
0.4$ kpc. No mixture of fundamental and first overtone RR Lyrae stars in the
either-or or bimodal region is seen in this cluster, as it seems to be the rule
for Oo~I clusters with a red horizontal branch. A multi-approach search in a
region of about 10$times$10 arcmin$^2$ around the cluster revealed no new
variable stars within the limitations of our CCD photometry.

Time-series emph{VI} CCD photometry of the globular cluster NGC 1261 is
employed to study its variable star population. A membership analysis of most
variables based on Gaia~DR2 proper motions and colours, was performed prior to
the estimation of the mean cluster distance and metallicity. For the member RR
Lyrae, their light curves were Fourier decomposed to calculate their individual
values of distance, [Fe/H], radius and mass. The $I$-band P-L for RR Lyrae
stars was also employed. Our best estimates of the metallicity and distance of
this Oo I cluster are [Fe/H]$_{rm ZW}$=$-1.42 pm 0.05$ dex and $d=17.2 pm
0.4$ kpc. No mixture of fundamental and first overtone RR Lyrae stars in the
either-or or bimodal region is seen in this cluster, as it seems to be the rule
for Oo~I clusters with a red horizontal branch. A multi-approach search in a
region of about 10$times$10 arcmin$^2$ around the cluster revealed no new
variable stars within the limitations of our CCD photometry.

http://arxiv.org/icons/sfx.gif

Comments are closed.