Issue |
A&A
Volume 413, Number 2, January II 2004
|
|
---|---|---|
Page(s) | 669 - 679 | |
Section | Stellar structure and evolution | |
DOI | https://doi.org/10.1051/0004-6361:20034151 | |
Published online | 18 December 2003 |
A large X-ray flare from the Herbig Ae star V892 Tau
1
Astrophysics Division – Research and Science Support Department of ESA, ESTEC, Postbus 299, 2200 AG Noordwijk, The Netherlands
2
INAF – Osservatorio Astronomico di Palermo, Piazza del Parlamento 1, 90134 Palermo, Italy
3
Università di Palermo – Dipartimento di Scienze Fisiche ed Astronomiche, Piazza del Parlamento 1, 90134 Palermo, Italy
Corresponding author: G. Giardino, ggiardin@rssd.esa.int
Received:
1
August
2003
Accepted:
30
September
2003
We report the XMM-Newton observation of a large X-ray flare from
the Herbig Ae star V892 Tau. The apparent low mass companion of
V892 Tau, V892 Tau NE, is unresolved by XMM-Newton. Nevertheless there is
compelling evidence from combined XMM-Newton and Chandra data that the
origin of the flare is the Herbig Ae star V892 Tau. During the
flare the X-ray luminosity of V892 Tau increases by a factor of
, while the temperature of the plasma increases from
keV to
keV. From the scaling of the flare
event, based on hydrodynamic modeling, we conclude that a 500 G
magnetic field is needed in order to confine the plasma. Under the
assumptions that a dynamo mechanism is required to generate such a
confining magnetic field and that surface convection is a necessary
ingredient for a dynamo, our findings provide indirect evidence for
the existence of a significant convection zone in the stellar
envelope of Herbig Ae stars.
Key words: stars: flare / stars: coronae / stars: formation / stars: pre-main sequence / stars: individual: V892 Tau
© ESO, 2004
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