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Deep optical study of the mixed-morphology supernova remnant G 132.7+1.3 (HB3)

By |2022-02-17T13:26:52+02:00February 17th, 2022|

We present optical ccd images of the large supernova remnant (SNR) G132.7 + 1.3 (HB3) covering its full extent for the first time, in the emission lines of H α+ [N II], [S II] and [O III], where new and known filamentary and diffuse structures are detected. These observations are supplemented by new low-resolution long-slit spectra and higher-resolution images in the same emission lines. Both the flux-calibrated images and spectra confirm that the optical emission originates from shock-heated gas since the [S II]/H α > 0.4.

Constraints on the structure and seasonal variations of Triton’s atmosphere from the 5 October 2017 stellar occultation and previous observations

By |2022-01-27T11:43:54+02:00January 27th, 2022|

A stellar occultation by Neptune's main satellite, Triton, was observed on 5 October 2017 from Europe, North Africa, and the USA. We derived 90 light curves from this event, 42 of which yielded a central flash detection. We aimed at constraining Triton's atmospheric structure and the seasonal variations of its atmospheric pressure since the Voyager 2 epoch (1989). We also derived the shape of the lower atmosphere from central flash analysis.

First deep images catalogue of extended IPHAS PNe

By |2021-09-01T16:00:37+03:00August 31st, 2021|

A significative fraction of all massive stars in the Milky Way move supersonically through their local interstellar medium (ISM), producing bow shock nebulae by wind-ISM interaction. The stability of these observed astrospheres around cool massive stars challenges precedent two-dimensional (magneto-)hydrodynamical simulations of their surroundings. We present three-dimensional magneto-hydrodynamical (3D MHD) simulations of the circumstellar medium of runaway M-type red supergiant stars moving with velocity v* = 50 km s−1 . We treat the stellar wind with ...

3D MHD astrospheres: applications to IRC-10414 and Betelgeuse

By |2021-07-17T12:35:25+03:00July 12th, 2021|

A significative fraction of all massive stars in the Milky Way move supersonically through their local interstellar medium (ISM), producing bow shock nebulae by wind-ISM interaction. The stability of these observed astrospheres around cool massive stars challenges precedent two-dimensional (magneto-)hydrodynamical simulations of their surroundings. We present three-dimensional magneto-hydrodynamical (3D MHD) simulations of the circumstellar medium of runaway M-type red supergiant stars moving with velocity v* = 50 km s−1 . We treat the stellar wind with ...

‘Ears’ formation in supernova remnants: overhearing an interaction history with bipolar circumstellar structures

By |2021-07-16T03:40:17+03:00April 1st, 2021|

A characteristic feature that is frequently found in nearby supernova remnants (SNRs) is the existence of two antisymmetric, local protrusions that are projected as two 'ears' in the morphology of the nebula. In this paper, we present a novel scenario for the 'ear' formation process,

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