We report on XMM-Newton observations of the young open cluster NGC 2547 which allow us to characterise 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 L _ { x } \simeq 10 ^ { 30.5 } erg s ^ { -1 } and declining to L _ { x } \leq 10 ^ { 29.0 } eg s ^ { -1 } among M-stars with masses \geq 0.2 M _ { \odot } .
Coronal spectra show evidence for multi-temperature differential emission measures and low coronal metal abundances of Z \simeq 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 super-saturated X-ray activity levels .
The median levels of L _ { x } and L _ { x } / L _ { bol } 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 .

Coronal temperatures increase with L _ { x } , L _ { x } / L _ { bol } and surface X-ray flux .
The most active solar-type stars in NGC 2547 have coronal temperatures intermediate between those in the ONC and the most active older ZAMS stars .
We show that simple scaling arguments predict higher coronal temperature in coronally saturated stars with lower gravities .
A number of candidate flares were identified among the low-mass members and a flaring rate ( for total flare energies [ 0.3–3 keV ] > 10 ^ { 34 } erg ) of 1 every 350 ^ { +350 } _ { -120 } ks was found for solar-type stars , which is similar to rates found in the ONC and Pleiades .
Comparison with ROSAT HRI data taken 7 years previously reveals that only 10–15 percent of solar-type stars or stars with L _ { x } > 3 \times 10 ^ { 29 } erg s ^ { -1 } exhibit X-ray variability by more than a factor of two .
This is comparable with clusters of similar age but less than in both older and younger clusters .
The similar median levels of X-ray activity and rate of occurrence for large flares in NGC 2547 and the ONC demonstrate that the X-ray radiation environment around young solar-type stars remains relatively constant over their first 30 Myr .