Issue |
A&A
Volume 384, Number 2, MarchIII 2002
|
|
---|---|---|
Page(s) | 603 - 619 | |
Section | The Sun | |
DOI | https://doi.org/10.1051/0004-6361:20011780 | |
Published online | 15 March 2002 |
High resolution near-infrared spectro-imaging of NGC 7027*
1
Institut d'Astrophysique Spatiale, Bât. 121, Université de Paris XI, 91405 Orsay, France
2
Physics Department, New York University, 4 Washington Place, New York, NY 10003, USA
3
Institut d'Astrophysique de Paris, CNRS, 98b bd. Arago, 75014 Paris, France
4
Institut d'Astrophysique de Marseille, CNRS & Univ. de Provence, BP 8, 13376 Marseille Cedex 12, France
5
Observatorio Astronómico Nacional (IGN), Apt 1143, 28800 Alcalá de Henares, Spain
6
Observatoire de Grenoble, BP 53X, 38041 Grenoble Cedex, France
Corresponding author: P. Cox, cox@ias.fr
Received:
7
August
2001
Accepted:
5
December
2001
We present near-infrared spectro-imaging of the young
planetary nebula NGC 7027 between 2.10 and 2.20 μm with high
spatial (0.5″) and high spectral () resolution. The observations, made using BEAR at the
CFHT, reveal the detailed morphology and kinematics of the ionized
nebula (in the Brγ line and 16 other atomic lines) and the
surrounding molecular envelope (in the 1–0 S(1) line of H2).
The observations show that the ionized gas forms an elongated (
,
), limb-brightened shell
with an expansion velocity of 19.5 along the line of sight. The
shell is composed of numerous small condensations and has nearly
parallel sides with flattened ends that are not well matched by a
uniform ellipsoidal model. Low level Brγ emission is detected
at high red- and blue-shifted velocities (
) along a
bipolar axis at
that deviates significantly from
that of the main nebula. The
emission is distributed at the
periphery of the ionized gas, in a limb-brightened, bi-conical shell
(
,
) with
enhanced emission at the equator and complex structure at the ends of
the major axis. The H2 emission traces the inner edge of the
extended molecular envelope seen in CO, and its distribution and
intensity are well matched by model predictions of a high-density
(
) photo-dissociation region.
The kinematic structure of the H2 emission reveals a remarkable
series of lobes and openings in the molecular shell. These features
are point symmetric about the center, and the most prominent pair
aligns with the high velocity, bipolar emission seen in Brγ.
These observations demonstrate recent activity by collimated outflows
in NGC 7027, with a multiple, bipolar geometry. The interaction of
the outflows with the surrounding envelope has significantly affected
the morphology of the developing nebula and its environment, and their
presence in this well-studied archetype underscores the general
importance of outflows in the early shaping history of planetary
nebulae.
Key words: infrared: ISM / ISM: lines and bands / ISM: molecules / planetary nebulae: general / planetary nebulae: individual: NGC 7027
© ESO, 2002
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