SIMBAD references

2019ApJS..244...12W - Astrophys. J., Suppl. Ser., 244, 12-12 (2019/September-0)

A search for variable stars in the globular cluster M4 with K2.


Abstract (from CDS):

We extract light curves for 4554 objects with 9 < G < 19 in the K2 superstamp observations of the globular cluster M4, including 3784 cluster members, and search for variability. Among cluster-member objects, we detect 66 variables, of which 52 are new discoveries. Among objects not belonging to the cluster, we detect 24 variables, of which 20 are new discoveries. We additionally discover 57 cluster-member suspected variables, 10 cluster-non-member suspected variables, and four variables with ambiguous cluster membership. Our light curves reach sub-millimagnitude precision for the cluster horizontal branch, permitting us to detect asteroseismic activity in six horizontal branch stars outside the instability strip and one inside the strip but with only ∼1 mmag amplitude variability. Nineteen additional stars along the red giant branch also have detected asteroseismic variability. Several eclipsing binaries are found in the cluster, including a 4.6 day detached eclipsing binary and an EW-class eclipsing binary, as well as an EW with uncertain cluster membership and three other candidate EWs. A 22 day detached eclipsing binary is also found outside the cluster. We identify a candidate X-ray binary that is a cluster member with quiescent and periodic ∼20 mmag optical variability. We also obtain high-precision light curves for 10 of the previously known RR Lyrae variables in the cluster and identify one as a candidate Blazhko variable with a Blazhko period in excess of 78 days. We make our light curves publicly available.

Abstract Copyright: © 2019. The American Astronomical Society. All rights reserved.

Journal keyword(s): Close binary stars - Detached binary stars - Semi-detached binary stars - Binary stars - Eclipses - Eclipsing binary stars - Globular star clusters - RR Lyrae variable stars - Variable stars - X-ray binary stars - W Ursae Majoris variable stars - Algol variable stars

VizieR on-line data: <Available at CDS (J/ApJS/244/12): table1.dat table2.dat table3.dat table4.dat table5.dat lcs/*>

Status at CDS : All or part of tables of objects could be ingested in SIMBAD with priority 2.

Simbad objects: 48

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