Astronomers Uncover Companion Cluster to Czernik 38

Astronomers from the National Research Institute of Astronomy and Geophysics (NRIAG) in Cairo, Egypt, have investigated a young open cluster known as Czernik 38. As a result, they found a new open cluster, which turns out to be a companion to Czernik 38. The discovery was detailed in a paper published Jan. 14 on the arXiv pre-print server. Open clusters (OCs), formed from the same giant molecular cloud, are groups of stars loosely gravitationally bound to each other. So far, more than 1,000 of them have been discovered in the Milky Way, and scientists are still looking for more, hoping to find a variety of these stellar groupings. Clump of stars nearby Czernik 38 is a young and rich OC in the constellation Serpens Cauda, at a distance of some 12,000 light years away from Earth. It consists of at least 900 stars and its age is estimated to be about 125 million years. A team of astronomers led by NRIAG's Nasser M. Ahmed has recently performed a comprehensive investigation of Czernik 38 by analyzing the data from ESA's Gaia satellite. The study led to a serendipitous identification of a clump of stars situated approximately 32 arcminutes away from the center of Czernik 38. "We discovered a clump of stars located at α = 282.11 ± 0.05 and δ = 4.56 ± 0.05 approximately 32 arcminutes from its center. We proposed that this clump may represent a new open star cluster and suspect it could be a companion to Czernik 38, as a binary open cluster," the researchers explain. A binary open cluster? Ahmed's team found that the radial density profile (RDP) of the detected clump fits appropriately with the King model—a mathematical tool used to describe the structure and density of star clusters. This allowed the astronomers to initially classify the clump as an open cluster and they named it Nasser 1. Further investigation of Nasser 1 found that it shares the same age, distance, and proper motion with Czernik 38. Moreover, it exhibits a significant reddening value similar to that of Czernik 38, and both clusters have a high rate of star formation. Furthermore, the astronomers identified 66 member stars of Nasser 1, with an average radial velocity at a level of 41.6 km/s. This is comparable to that of Czernik 38's, which was calculated to be 46.1 km/s. Once together According to the paper, the Czernik 38-Nasser 1 cluster system has a single Gaussian mass distribution or a one mass population. This suggests that it was once a single cluster that had been violently torn apart by strong tidal forces during its orbital journey. The study also found that the newfound cluster system exhibits unique complex tides. It turned out that both clusters are affected by the impacts of differential rotation tides, as evidenced by their elongations in the direction of orbital motion. In addition, Nasser 1 is affected by a gravitational tide caused by the Carina-Sagittarius spiral arm. © 2026 Science X Network