According to RT, variable stars are defined as those whose light varies strongly and noticeably, due to some changes that occur in the star’s core, which leads to a change in its light and size.
Star clusters provide excellent opportunities to study stellar evolution because they are groups of stars with similar characteristics, for example, age, distance, and initial composition.
In particular, astronomers often look to variable stars in small and medium age groups, which can be crucial in developing an understanding of PMS stars and thus the initial stages of stellar evolution.
NGC 559 is located about 7,900 light-years from Earth, and is an open cluster estimated to be 224 million years old.
A team of astronomers led by Yogesh C.Goshie, of the Aryabhata Institute for Observational Science Research (ARIES) in India, has released the results of a long-range photometric study of NGC 559 as part of a broader observation campaign of some poorly studied small and middle-aged open groups.
For this purpose, they used different telescopes from one to two meters class located in India. The observations, which lasted more than three years, led to the discovery of dozens of new variants in NGC 559.
“This work presents the first long-range scanning of optical changes to the medium-aged open cluster NGC 559. We conducted a large-scale multi-site campaign to collect fifth-scale photometric data for the cluster field in 40 nights over a period of more than three years,” astronomers wrote in the paper. .
In total, the study discovered 70 new star variations, including 67 cyclic variables (their brightness changes steadily) with cycles ranging from three hours to 41 days. Most of them have a relatively small difference. The remaining three stars are objects with irregular changes in brightness.
Of all the periodic variables mentioned in the paper, 30 stars are classified as cluster members (with estimated masses between 1.72 and 3.6 solar masses), while 37 stars belong to the star cluster (a group of stars within the galaxy that are similar to each other in spatial distribution. , Chemical and mineral composition, and have the same age).
Eleven stars were categorized as non-pulsating variables, five as rotational variables, three as slow-pulsing B stars, two as FK Comae Berenices, one as an Algol binary star, and one as a potential blue hobo, while The nature of the other seven stars remains unspecified.
Additional optical and spectral observations are needed to shed more light on the nature of these space objects.