An XMM-Newton observation of the young open cluster NGC 2547: coronal activity at 30 Myr
Abstract
We report on XMM-Newton observations of the young open cluster NGC 2547 which allow us to characterize coronal activity in solar-type stars, and stars of lower mass, at an age of 30 Myr. X-ray emission is seen from stars at all spectral types, peaking among G stars at luminosities (0.3-3 keV) of Lx≃ 1030.5 erg s-1 and declining to Lx≤ 1029.0 erg s-1 among M stars with masses ≥0.2 M⊙. Coronal spectra show evidence for multi-temperature differential emission measures and low coronal metal abundances of Z≃ 0.3. The G- and K-type stars of NGC 2547 follow the same relationship between X-ray activity and Rossby number established in older clusters and field stars, although most of the solar-type stars in NGC 2547 exhibit saturated or even supersaturated X-ray activity levels. The median levels of Lx and Lx/Lbol in the solar-type stars of NGC 2547 are very similar to those in T-Tauri stars of the Orion Nebula cluster (ONC), but an order of magnitude higher than in the older Pleiades. The spread in X-ray activity levels among solar-type stars in NGC 2547 is much smaller than in older or younger clusters.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- April 2006
- DOI:
- 10.1111/j.1365-2966.2005.09988.x
- arXiv:
- arXiv:astro-ph/0512441
- Bibcode:
- 2006MNRAS.367..781J
- Keywords:
-
- stars: activity;
- stars: coronae;
- stars: late-type;
- stars: rotation;
- open clusters and associations: individual: NGC 2547;
- X-rays: stars;
- Astrophysics
- E-Print:
- Accepted for publication in MNRAS. Electronic tables available from the author