Young open cluster Messier 39 investigated in detail

Italian astronomers have carried out high-resolution spectroscopic observations of a younger open cluster generally known as Messier 39. Outcomes of the observational marketing campaign, offered in a paper published Dec. 14 on the pre-print server arXiv, yield important details about the cluster’s chemical composition.

Open clusters (OCs), shaped from the identical large molecular cloud, are teams of stars loosely gravitationally certain to one another. To date, greater than 1,000 of them have been found within the Milky Way, and scientists are nonetheless searching for extra, hoping to search out quite a lot of these stellar groupings. Increasing the listing of identified galactic open clusters and finding out them intimately could possibly be essential for bettering our understanding of the formation and evolution of our galaxy.

Messier 39 (or M39 for brief, also referred to as NGC 7092) is a younger Galactic open cluster positioned some 1,000 mild years away within the constellation Cygnus. The cluster has a linear tidal radius of 28 mild years, a mass of about 232 solar masses, and its age is estimated to be roughly 280 million years.

Nevertheless, though Messier 39 was found nearly three centuries in the past, it has not been noticed with high-resolution spectroscopy but and its chemical composition stays unknown. That’s the reason a crew of astronomers led by Javier Alonso-Santiago of the Catania Astrophysical Observatory in Italy, determined to conduct such observations of this cluster utilizing the Excessive Accuracy Radial velocity Planet Searcher for the Northern hemisphere spectrograph (HARPS-N) and the Fiber-fed Echelle Spectrograph (FIES).

“We centered on M 39, a close-by younger open cluster little studied in recent times, whose chemical composition was to date unknown. We carried out high-resolution spectroscopy with the HARPS-N and FIES spectrographs for 20 seemingly cluster members that had been supplemented with archival photometry and Gaia DR3 knowledge,” the researchers defined.

Initially, the crew recognized 260 seemingly members of Messier 39 inside a radius of 250 arcminutes across the nominal cluster heart. It turned out that the three recognized members are double-lined spectroscopic binary techniques, and that there aren’t any developed stars on this pattern. By analyzing the spatial distribution of those members, a distance to Messier 39 was inferred to be roughly 980 light years.

The astronomers managed to derive radial and projected rotational velocities of the celebrities of their pattern. They discovered that a lot of the stars have rotational velocities starting from −6 to −3 km/s, and a imply radial velocity for Messier 39 was calculated to be −5.46 km/s. Additionally they estimated the extinction and the atmospheric parameters of those stars.

The authors of the examine carried out the chemical analysis for the 9 coolest stars within the pattern (with efficient temperatures beneath 7,100 Okay), figuring out abundances for 21 parts. They discovered that Messier 39 has a solar-like metallicity (0.04 dex) and that the investigated stars have a chemical composition much like that of the sun.

The researchers famous that solely sodium exhibits a decrease abundance within the studied pattern, whereas sulfur and the heaviest parts, particularly barium, show increased values. Furthermore, it was discovered that Messier 39 exhibits solar-like imply ratios for alpha parts and iron-peak parts to iron, whereas for the neutron-capture parts this ratio is barely overabundant.

Primarily based on these outcomes, the scientists concluded that the chemical composition of this cluster is totally appropriate with that of the Galactic skinny disk.

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