# The Environments around W Serpentis Systems: Independent Limits on System Masses and Extended Envelopes

**Authors:** T. J. Davidge  
**arXiv:** [2304.00080](https://arxiv.org/abs/2304.00080)  
**Date:** 2023-03-31  
**Summary page:** https://www.summarizepaper.com/en/paper/2304.00080v1/

## Key points

- T.J. Davidge used GAIA Data Release 3 to investigate stellar contents within projected separations of 10 parsecs from eight close binary systems
- Aim was to search for remnant star clusters or moving groups with proper motions similar to those of the binaries
- W Ser stars tend to be accompanied by companions with separations on parsec or larger scales
- Study identified at least three candidate companions within the search area for each system, although in most cases, the numbers were much higher
- Evidence presented that SX Cas is near the center of a diffuse cluster
- Color-magnitude diagrams (CMDs) of groupings associated with binaries were compared with isochrones, and it was found that most groupings had ages exceeding 1 Gyr, indicating an intermediate age
- Masses of stars at the main sequence turn-off were estimated and provided insights into the initial mass of donor stars in each binary system
- Images from WISE Allsky survey were used to search for circumsystem envelopes, and extended thermal emission was found around six systems in W2 images (~4.5um)
- Study provides independent limits on system masses and extended envelopes around W Serpentis systems and related objects which suggest that these systems may be associated with remnant star clusters or moving groups and provide insights into their formation and evolution processes

## Summary

In a recent study, T. J. Davidge used data from the GAIA Data Release 3 to investigate the stellar contents within projected separations of 10 parsecs from eight close binary systems that are either classical W Serpentis systems or related objects. The aim was to search for remnant star clusters or moving groups with proper motions similar to those of the binaries. While some of the binary systems had distinct proper motions from those of the majority of stars within the search area, there was still a tendency for W Ser stars to be accompanied by companions with separations on parsec or larger scales. The study identified at least three candidate companions within the search area for each system, although in most cases, the numbers were much higher. Evidence was presented that SX Cas is near the center of a diffuse cluster. Color-magnitude diagrams (CMDs) of groupings associated with binaries were compared with isochrones, and it was found that most groupings had ages exceeding 1 Gyr, indicating an intermediate age. The masses of stars at the main sequence turn-off were estimated and provided insights into the initial mass of donor stars in each binary system. Images from the WISE Allsky survey were also used to search for circumsystem envelopes, and extended thermal emission was found around six systems in W2 (i.e., ~4.5um) images. Overall, this study provides independent limits on system masses and extended envelopes around W Serpentis systems and related objects which suggest that these systems may be associated with remnant star clusters or moving groups and provide insights into their formation and evolution processes.