Astronomers explore globular cluster NGC 2419

Utilizing the Indian Astronomical Observatory (IAO) and ESA’s Gaia satellite, astronomers have explored a galactic globular cluster often known as NGC 2419. Outcomes of the examine, published April 29 on the preprint server arXiv, shed extra gentle on the properties of this cluster and its stellar content material.

Globular clusters (GCs) are collections of tightly certain stars orbiting galaxies. Astronomers understand them as pure laboratories enabling research on the evolution of stars and galaxies. Particularly, globular clusters might assist researchers to raised perceive the formation historical past and evolution of early-type galaxies, because the origin of GCs appears to be intently linked to intervals of intense star formation.

Situated some 300,000 gentle years away from Earth, NGC 2419 is likely one of the most distant globular clusters within the outer halo of our galaxy. With a radius of 260 gentle years, mass of about 900,000 solar plenty and an absolute magnitude of -9.42 magazine, it is usually one of the vital huge and brightest galactic GCs.

Provided that the inhabitants of variable stars in NGC 2419 is kind of wealthy, a workforce of astronomers led by Armando Arellano Ferro of the Nationwide Autonomous College of Mexico (UNAM), determined to analyze the stellar content material of this cluster, focusing primarily on its variables. For this objective they used IAO’s 2m telescope and knowledge from Gaia’s Knowledge Launch 3 (DR3).

Ferro’s workforce was capable of receive photometry for 1,107 level sources within the area of NGC 2419. The sunshine curves embody 74 of the identified variable stars within the cluster, and primarily based on these variables, the astronomers produced a shade magnitude diagram (CMD).

Based on the examine, the radial distribution of members of NGC 2419 signifies the prolonged attain of the cluster to distances of about 456 gentle years. This discovering makes NGC 2419 one of many largest clusters within the Milky Way.

Primarily based on the sunshine curves of RR Lyrae variable stars in NGC 2419, the authors of the paper estimated the imply metallicity and distance to the cluster. It was discovered that NGC 2419 has a metallicity of roughly -1.89 and is situated about 270,000–281,000 light years away.

The examine additionally discovered that certainly one of variables in NGC 2419 of the W Virginis kind, designated V18, has advanced from a zero-age-horizontal-branch (ZAHB) blue tail progenitor (with a total mass of about 0.54 solar plenty) with a really skinny shell (with a mass of solely 0.04 solar masses). This might have implications for our understanding of the evolution of Inhabitants II Cepheids—previous, sometimes metal-poor, low-mass variables pulsating with intervals sometimes between 1 and 50 days. W Virginis variables are a subclass of Inhabitants II Cepheids.

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