Time evolution of X-ray coronal activity in PMS stars; a possible relation with the evolution of accretion disks

Details Time evolution of X-ray coronal activity in PMS stars; a possible relation with the evolution of accretion disks Time evolution of X-ray coronal activity in PMS stars; a possible relation with the evolution of accretion disks

2003-02-17

arxiv.org/abs/astro-ph/0302329v1

Astron.Astrophys.402:277-292,2003

Astronomy and Astrophysics

Astrophysics

17 pages, 8 figures, accepted for publication in A&A

Scientific paper

10.1051/0004-6361:20030203

We investigate the evolution of X-ray stellar activity from the age of the youngest known star forming regions (SFR), < 1Myr, to about 100 Myr, i.e. the zero age main sequence (ZAMS) for a ~ 1M_sun star. We consider five SFR of varying age (Rho Ophiuchi, the Orion Nebula Cluster, NGC 2264, Chamaeleon I, and Eta Chamaeleontis) and two young clusters (the Pleiades and NGC 2516). Optical and X-ray data for these regions are retrieved both from archival observations and recent literature, and reanalyzed here in a consistent manner so to minimize systematic differences in the results. We study trends of L_X and L_X/L_bol as a function of stellar mass and association age. For low mass stars (M < 1M_sun) we observe an increase in L_X/L_bol in the first 3-4 Myr and a subsequent leveling off at the saturation level (L_X/L_bol ~ -3). Slowly evolving very low mass stars then retain saturated levels down to the oldest ages here considered, while for higher mass stars activity begins to decline at some age after ~10^7 years. We find our data consistent with the following tentative picture: low mass PMS stars with no circumstellar accretion disk have saturated activity, consistently with the activity-Rossby number relation derived for MS stars. Accretion and/or the presence of disks somehow lowers the observed activity levels; disk dissipation and/or the decrease of mass accretion rate in the first few Myrs of PMS evolution is therefore responsible for the observed increase of L_X/L_bol with time.

Affiliated with

Also associated with

No associations

Rating

Time evolution of X-ray coronal activity in PMS stars; a possible relation with the evolution of accretion disks does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Time evolution of X-ray coronal activity in PMS stars; a possible relation with the evolution of accretion disks, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Time evolution of X-ray coronal activity in PMS stars; a possible relation with the evolution of accretion disks will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-381108