Work

A rotation-based census of blue lurker candidates in open clusters

Year: 2026

Type: article

Abstract: Aims . We have compiled a list of blue lurker (BL) candidates in open clusters using the available rotation catalogs. Blue lurkers are rejuvenated main-sequence stars hidden among normal main-sequence stars on color-magnitude diagrams of star clusters. In comparison to BLs, blue straggler stars, which formed via similar mass transfers or mergers, occupy a distinct space in color-magnitude diagrams. Methods . Blue lurkers can be identified by their unusually faster rotation compared to similar mass stars, which is a signature of recent accretion, or by the presence of a companion (e.g., an extremely low mass white dwarf), which can only be formed by mass donation. We searched for fast-rotating stars on the main sequence of open clusters using Kepler, TESS, and spectroscopic rotation indicators, such as rotation periods and v sin i measurements. Results . We identified 97 new BL candidates across 35 open clusters, almost tripling the previously known sample of 36. Based on the estimated completeness of ≈3%, thousands of BLs are likely hidden within the cluster population. Detailed spectroscopic and time series analyses will be essential to confirming their mass-transfer histories.

Source: Astronomy and Astrophysics

DOI: 10.1051/0004-6361/202558188

Authors: Vikrant V. Jadhav, Khushboo K. Rao, Elisabetta Reggiani

Institutions: Charles University, National Central University, Arcetri Astrophysical Observatory, University of Florence, National Institute for Astrophysics

Language: English

Topic: Stellar, planetary, and galactic studies

Subfield: Astronomy and Astrophysics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $1,865

Funder: European Commission