Details

Autor(en) / Beteiligte

• Ingleby, Laura
• Calvet, Nuria
• Hernández, Jesus
• Briceño, Cesar
• Espaillat, Catherine
• Miller, Jon
• Bergin, Edwin
• Hartmann, Lee

Titel

Evolution of X-ray and Far-ultraviolet Disk-dispersing Radiation Fields

Ist Teil von

• The Astronomical journal, 2011-04, Vol.141 (4), p.127-jQuery1323898020817='48'

Ort / Verlag

United States: IOP Publishing

Erscheinungsjahr

2011

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• We present new X-ray and far-ultraviolet (FUV) observations of T Tauri stars covering the age range 1-10 Myr. Our goals are to observationally constrain the intensity of radiation fields responsible for evaporating gas from the circumstellar disk and to assess the feasibility of current photoevaporation models, focusing on X-ray and UV radiation. We greatly increase the number of 7-10 Myr old T Tauri stars observed in X-rays by including observations of the well-populated 25 Ori aggregate in the Orion OB1a subassociation. With these new 7-10 Myr objects, we confirm that X-ray emission remains constant from 1 to 10 Myr. We also show, for the first time, observational evidence for the evolution of FUV radiation fields with a sample of 56 accreting and non-accreting young stars spanning 1 Myr to 1 Gyr. We find that the FUV emission decreases on timescales consistent with the decline of accretion in classical T Tauri stars until reaching the chromospheric level in weak T Tauri stars and debris disks. Overall, we find that the observed strength of high-energy radiation is consistent with that required by photoevaporation models to dissipate the disks in timescales of approximately 10 Myr. Finally, we find that the high-energy fields that affect gas evolution are not similarly affecting dust evolution; in particular, we find that disks with inner clearings, transitional disks, have similar levels of FUV emission as full disks.