Astronomers investigate giant stars in open cluster NGC 6866

Utilizing NASA’s Kepler and ESA’s Gaia spacecraft, a world staff of astronomers has performed an astroseismic investigation of six big stars within the open cluster NGC 6866. The research, offered August 24 on the pre-print server arXiv, sheds extra mild on the properties of those big stars and the cluster itself.

Open clusters (OCs), fashioned from the identical big molecular cloud, are teams of stars loosely gravitationally certain to one another. To this point, greater than 1,000 of them have been found within the Milky Way, and scientists are nonetheless on the lookout for extra, hoping to search out quite a lot of these stellar groupings. Increasing the checklist of recognized galactic open clusters and learning them intimately may very well be essential for bettering our understanding of the formation and evolution of our galaxy.

Found in 1783, NGC 6866 (also called OCL 183) is a comparatively younger (estimated to to be between 480 and 780 million years previous) OC within the constellation Cygnus, at a distance of about 3,900 light years away. Nonetheless, though the cluster is thought for greater than two centuries, lots of its properties, together with age are nonetheless unsure.

That’s the reason a gaggle of astronomers led by Karsten Brogaard of the College of Bologna in Italy, determined to establish and examine oscillating big members of the open cluster NGC 6866, utilizing them to constrain cluster properties. For this goal, they analyzed the outcomes from Gaia’s Knowledge Launch 3 (DR3) and photometric mild curves from the Kepler spacecraft.

“We establish six big members of NGC 6866 by way of photometry, correct motions, and parallaxes from Gaia and spectroscopic literature measurements. These are mixed with asteroseismic measurements which we derive utilizing photometric knowledge from the Kepler mission for 5 of the celebs,” the researchers defined.

The astronomers chosen and examined six giant stars within the helium-core burning (HeCB) phase, particularly: KIC 8461659, KIC 8329894, KIC 8395903, KIC 8264549, KIC 7991875 and KIC 8264592. All these stars have related efficient temperatures—at a stage of 5,100 Ok.

The research discovered that the six giants have a imply radius of about 10.1 solar radii and a imply mass of round 2.8 solar lots. The astronomers underlined that the investigated stars are due to this fact considerably smaller than predicted by present one-dimensional stellar fashions.

In line with the paper, the six stars have been discovered to be between 443 and 580 million years previous. By evaluating all of the collected knowledge to stellar-model isochrones the age of NGC 6866 was estimated to be 430 million years, thus the cluster seems to be youthful than beforehand thought.

The researchers added that future asteroseismic missions, just like the deliberate ESA’s Excessive-precision AsteroseismologY of DeNse (HAYDN) stellar fields, have the potential to uncover extra particulars concerning the properties of stars in NGC 6866 and in different younger open clusters.

© 2023 Science X Community