Astronomers study globular cluster NGC 2419

Using the Indian Astronomical Observatory (IAO) and ESA’s Gaia satellite, astronomers explored a globular cluster called NGC 2419. Their findings, published on April 29 on the preprint server arXiv, shed further light on the properties of this cluster and its surrounding outstanding content. Globular clusters (GCs) are closely connected collections of stars orbiting the galaxy. Astronomers consider them natural laboratories that allow the study of the evolution of stars and galaxies. Globular clusters in particular could help researchers better understand the formation history and evolution of early galaxy types, as the origin of GCs seems to be closely linked to periods of intense star formation. Located about 300,000 light-years from Earth, NGC 2419 is one of the most distant globular clusters in the galaxy’s outer halo. Its radius is 260 light years, its mass is approximately 900,000 solar masses, and its absolute brightness is -9.42 mag. It is also one of the most massive and brightest galactic GCs. Given that NGC 2419 has a very rich population of variable stars, a team of astronomers led by Armando Arellano Ferro from the National Autonomous University of Mexico (UNAM) focused primarily on variable stars and I decided to study the contents of the stars. . For this purpose, they used data from his IAO’s 2-meter telescope and Gaia’s Data Release 3 (DR3). Ferro’s team was able to perform photometry of his 1,107 point sources in situ at NGC 2419. The light curve includes his 74 known variable stars in the cluster, and based on these variable stars, astronomers created a color magnitude diagram (CMD). According to the study, the radial distribution of NGC 2419’s members suggests that the cluster reaches a distance of about 456 light-years. This discovery makes NGC 2419 one of the largest star clusters in the Milky Way. Based on the light curve of NGC 2419’s variable star RR Lyra, the authors estimated the average metallicity and distance to the cluster. NGC 2419 was found to have a metallicity of about -1.89 and is located about 270,000 to 281,000 light years away. The study also shows that one of the W Virginis-type NGC 2419 variable stars (called V18) arose from a very massive zero-age horizontal branch (ZAHB) blue-green precursor (approximately 0.54 solar masses). It turned out that there was something. Thin shell (mass only 0.04 solar masses). This may have implications for our understanding of the evolution of population II Cepheids. Cepheids are ancient, typically metal-poor, low-mass variables that typically pulsate with periods between 1 and 50 days. The W virginis variable is a subclade of Population II Cepheids.

source:https://dx.doi.org/10.48550/arxiv.2404.19151