  The origin and evolution of supernova remnants of the mixed-morphology class
is not well understood. Several remnants present distorted radio or X-ray
shells with jet-like structures. G290.1-0.8 (MSH 11-61A) belongs to this class.
We aim to investigate the nature of this supernova remnant in order to unveil
the origin of its particular morphology. We based our work on the study of the
X-ray emitting plasma properties and the conditions imposed by the cold
interstellar medium where the remnant expanded. We use archival radio, HI line
data and X-ray observations from XMM-Newton and Chandra observatories, to study
G290.1-0.8 and its surrounding medium. Spatially resolved spectral analysis and
mean photon energy maps are used to obtain physical and geometrical parameters
of the source. Radio continuum and HI line maps give crucial information to
understand the radio/X-ray morphology. The X-ray images show that the remnant
presents two opposite symmetric bright spots on a symmetry axis running towards
the NW-SE direction. Spectral analysis and mean photon energy maps confirm that
the physical conditions of the emitting plasma are not homogeneous throughout
the remnant. In fact, both bright spots have higher temperatures than the rest
of the plasma and its constituents have not reached ionization equilibrium yet.
HI line data reveal low density tube-like structures aligned along the same
direction. This evidence supports the idea that the particular X-ray morphology
observed is a direct consequence of the structure of the interstellar medium
where the remnant evolved. However, the possibility that an undetected
point-like object, as a neutron star, exists within the remnant and contributes
to the X-ray emission cannot be discarded. Finally, we suggest that a supernova
explosion due to the collapse of a high-mass star with a strong bipolar wind
can explain the supernova remnant morphology.
