| Issue |
A&A
Volume 495, Number 2, February IV 2009
|
|
|---|---|---|
| Page(s) | L13 - L16 | |
| Section | Letters | |
| DOI | https://doi.org/10.1051/0004-6361/200811535 | |
| Published online | 09 February 2009 | |
Letter to the Editor
Discovery of an old photoevaporating disk in σ Orionis *
1
Osservatorio Astrofisico di Arcetri, INAF, Largo E. Fermi 5, 50125 Firenze, Italy e-mail: erigliaco@arcetri.astro.it
2
Università di Firenze, Dipartimento di Astronomia, Largo E. Fermi 2, 50125 Firenze, Italy
3
Osservatorio Astronomico di Palermo, INAF, Piazza del Parlamento 1, 90134 Palermo, Italy
Received:
17
December
2008
Accepted:
2
February
2009
The photoevaporation of circumstellar disks is a powerful process in the
disk dissipation
at the origin of the Orion proplyds.
This Letter reports the first detection of a photoevaporating disk
in the final but long-lasting phase of its evolution.
The disk is associated to a low-mass T Tauri member
of the σ Ori Cluster. It is
characterized by a very low (if any) accretion rate
and by a tenuous (
/yr) photoevaporation
wind, which is unambiguously detected in the
optical spectrum of the object. The wind
emits strong forbidden lines of [SII] and [NII]
because the low-mass star is close to a
powerful source of ionizing photons,
the O9.5 star σ Ori.
Key words: stars: formation / accretion, accretion disks
© ESO, 2009
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