Abstract

Contributed Talk - Splinter StarFormation   (MW-1250)

Volans-Carina, An X-ray Bridge Between Younger and Older Stellar Populations

Daniela Muñoz Giraldo, Beate Stelzer, Alex Binks
Institut für Astronomie und Astrophysik, Eberhard Karls Universität Tübingen

Studying the early evolution of coronal activity is a key ingredient for understanding how stellar feedback shapes star-forming environments (SFEs) across multiple scales, from the irradiation of protoplanetary disks to the integrated X-ray output of stellar populations in galaxies. The nearest SFEs lie beyond ~100 pc, limiting the completeness of stellar X-ray censuses. Fortunaly, nearby young moving groups, with ages between 10-150 Myr, provide an essential observational bridge between embedded star-forming regions and older open clusters by tracing the evolution of coronal activity after the dispersal of the natal cloud. At a distance of ~100 pc and an age of ~85 Myr, the Volans-Carina association (VCA) occupies a sparsely sampled stage of pre-main-sequence evolution. Its compact size and sparse population (63 members) enable one of the most complete X-ray censuses currently achievable for an intermediate-age association. We revisit the VCA list originally compiled by Gagné et al. (2018) combining Gaia DR3 astrometry with new radial velocities, refining the membership status and improving reliability for future population studies. Combining observations from ROSAT, eROSITA, and XMM-Newton, we achieve X-ray coverage for 94% of the stars in the VCA. We reconstruct the X-ray luminosity function down to ~0.2Msolar with minimal bias from upper limits. The X-ray and X-ray-to-bolometric luminosity distributions enable direct comparisons with both younger star-forming regions and older open clusters, providing a benchmark for the evolution of coronal activity at intermediate ages. Our X-ray census of the VCA provides observational constraints that can be incorporated into models connecting stellar magnetic activity, circumstellar disk evolution, and feedback in star-forming environments, illustrating how studies of nearby stellar populations can inform star formation across larger physical scales.