G 70.7+1.2 : supernova, nova, or stellar shell ?
Abstract
The paper presents a set of various data ranging from radio to X-ray wavelengths, including optical spectroscopy and infrared spectrophotometry, of the galactic source G70.7 + 1.2 whose nature has recently been assessed contradictorily. The observations definitely confirm the presence of a spherical shock wave expanding in a very dense environment. This shock wave accelerates the relativistic electrons responsible for the shell structure of the radio emission. It is suggested that G70.7 + 1.2 could be a young and compact supernova remnant in a high density medium which absorbs part of the nonthermal radio emission, accounting for the turnover in the low frequency spectrum (absorption by thermal electrons). The lower than normal radio luminosity may indicate that the emission is only just turning on, although other possibilities are also likely. The central object, which dominates the near-infrared emission, could be a supergiant star ejecting an envelope. The interaction of ejected matter with the interstellar cloud would lead to the formation of a shock wave propagating in the cloud. G70.7 + 1.2 might also be interpreted as the remnant of a nova event.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- March 1988
- Bibcode:
- 1988A&A...193..248J
- Keywords:
-
- Infrared Radiation;
- Radio Sources (Astronomy);
- Stellar Radiation;
- Stellar Spectrophotometry;
- Supergiant Stars;
- Supernovae;
- Emission Spectra;
- Infrared Astronomy Satellite;
- Relativistic Particles;
- Very Large Array (Vla);
- X Ray Astronomy;
- Astrophysics