The molecular structure of CRL 618.
Abstract
Spectroscopy and mapping of the type I postmain-sequence source CRL 618, taken with the 45-m antenna of the Nobeyama Radio Observatory and the 12-m NRAO facility at Kitty Peak, are presented. It is shown that the exterior constant velocity envelope has a typical aspect ratio of about 0.8, extends over a range not less than 70 arcsec, and has an FWHM close to about 50 arcsec. Spatial-velocity maps through the nucleus reveal appreciable asymmetries in right ascension, with emission peaking towards about V(lsr) of -25 km/s for easterly offset locations, and about -15 km/s towards the west. These characteristics may arise from a mix of transverse expansion in the bipolar lobes, radial expansion within the outflow cavities, and shock deceleration of the interior H I/H II wind.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- July 1992
- Bibcode:
- 1992A&A...260..283P
- Keywords:
-
- Astronomical Spectroscopy;
- Carbon Monoxide;
- Carbon Stars;
- Molecular Flow;
- Symbiotic Stars;
- Asymptotic Giant Branch Stars;
- Molecular Structure;
- Radio Spectra;
- Astrophysics