# Study of X-ray emission from the old open cluster, M67

Source: [Study of X-ray emission from the old open cluster, M67](<https://www.sota2.com/research/paper/68fa31f51e209131ce883908>)

Collection index: [llms.txt](<https://www.sota2.com/research/llms.txt>)

Data updated: 2025-10-27T03:35:51.468Z

Authors: K. P. Mooley, K. P. Singh

Published: 2015-07-02T20:37:01.000Z

## Abstract

We present an X-ray analysis of a 4 Gyr old open cluster, M67, using archival XMM-Newton data. The aim of this study was to find new X-ray members of M67, and to use the updated member list for studying X-ray variability, and derive the X-ray luminosity functions (XLFs) of different stellar types and compare them with other star clusters of similar age. We report the detection of X-ray emission from 25 members of M67, with membership based primarily on their proper motion, of which one X-ray source is a new member. Supplementing this study with previous ROSAT and Chandra studies of M67, and using the most recent proper motion study by Vereshchagin et al., we have compiled a revised list of X-ray emitting members of M67 consisting of 43 stars. Sixteen of these are known RS CVn type binaries having orbital periods $\<$ 10 days, and near-circular orbits, 5 are contact binaries with orbital periods $\<$ 6 hours, 5 are yellow and blue stragglers, 2 are Algol-type binaries, and one source is a cataclysmic variable. Fourteen members do not have any orbital information and cannot be classified. Fourteen of the X-ray sources detected do not have any optical counterpart down to a magnitude of $V\\simeq22$, and their membership is uncertain. Finally, we report the X-ray luminosity functions of RS CVn type and other types of stars in M67 and compare them with other open clusters of intermediate-to-old age.

## Recorded benchmark results

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## Original sources and implementation

[Original paper](<https://arxiv.org/abs/1507.00759>)

[PDF](<https://arxiv.org/pdf/1507.00759.pdf>)