Issue |
A&A
Volume 398, Number 1, January IV 2003
|
|
---|---|---|
Page(s) | 181 - 194 | |
Section | Interstellar and circumstellar matter | |
DOI | https://doi.org/10.1051/0004-6361:20021634 | |
Published online | 14 January 2003 |
The dynamics of the nebula M1-67 around the run-away Wolf-Rayet star WR 124
1
Astronomical Institute, Princetonplein 5, 3584 CC Utrecht, The Netherlands
2
SRON Laboratory for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands
Corresponding author: H. J. G. L. M. Lamers, lamers@astro.uu.nl
Received:
18
July
2002
Accepted:
7
November
2002
A new point of view on the dynamics of the circumstellar nebula
M1-67 around the run-away Wolf-Rayet (WR) star WR 124 is presented.
We simulated the outbursts of nebulae
with different morphologies, to compare the results to the
observed dynamical spectra of M1-67. We found that it has been
interacting with the surrounding ISM and has formed a bow shock
due to its high velocity of about relative to the
local ISM. The star is about 1.3 parsec away from the front of this
bow shock. The outbursts that are responsible for the nebula are
assumed to be discrete outbursts that occurred inside this
bow shock. The ejecta collide with this bow shock shortly after the
outburst. After the collision, they are
dragged away by the pressure of the ISM, along the surface of the
bow shock. The bow shock is oriented in such way that we are looking from
the rear into this paraboloid, almost along the main axis.
Evidence for this is given firstly by the fact that the far
hemisphere is much brighter than the near hemisphere, secondly by
the fact that there is hardly any emission found with radial
velocities higher than the star's radial velocity, thirdly by the fact
that the star looks to be in the centre of the nebula, as seen
from Earth, and finally by the asymmetric overall velocity distribution of
the nebula, which indicates higher radial velocities in the
centre of the nebula, and lower velocities near the edges.
We find evidence for at least two discrete outbursts that occurred inside
this bow shock. For these outbursts, we find expansion velocities of
and dynamical timescales of about 0.8 and
yr,
which are typical values for LBV outbursts. We therefore conclude
that M1-67 originates from several outbursts that occurred inside the bow shock
around WR 124, during an LBV phase that preceded the current WR phase of the star.
Key words: stars: circumstellar matter / stars: individual: WR 124 / stars: mass-loss / stars: Wolf-Rayet / ISM: individual objects: M1-67 / ISM: jets and outflows
© ESO, 2003
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