Nova Cassiopeiae 1993
Abstract
S. Boyle, University of London Observatory, reports: "Nova Cas 1993 was observed with the cassegrain spectrograph on the 0.6-m Allen reflector at Mill Hill during January and February. The most recent spectrum (range 505-675 nm, resolution 1.0 nm), obtained on Feb. 20.82 UT, suggests that the nova is entering (or has entered) its nebular phase. The iron lines seen in earlier spectra were not detected. Emission lines at 557.7 nm, 630.0 nm and 636.4 nm ([O I] forbidden lines) were detected. These lines were observed to be narrower, and stronger relative to H-alpha, than in a spectrum obtained on Feb. 7. The 'main' emission-line due to H-alpha also narrowed between Feb. 7 and 20. A further emission line, with intensity 0.3 of the main H-alpha emission line, appears at 659.9 nm in the Feb. 20 spectrum. If this line also arises from H-alpha, it represents a doppler velocity of about 1700 km/s." Further visual magnitude estimates: Feb. 18.21 UT, 10.8 (O. Midtskogen, Tranby, Norway); 18.75, 11.2 (B. H. Granslo, Fjellhamar, Norway); 19.22, 11.4 (P. Schmeer, Bischmisheim, Germany); 19.88, 11.6 (G. Comello, Groningen, Netherlands); 20.06, 12.1 (Granslo); 20.80, 12.3 (G. Poyner, Birmingham, England); 21.10, 12.7 (R. King, Duluth, MN); 22.13, [13.3 (R. Royer, Lakewood, CA); 22.42, 12.7 (P. Dombrowski, Glastonbury, CT); 22.76, 13.9 (Midtskogen); 22.86, 13.5 (S. Meister, Bulach, Switzerland).
- Publication:
-
International Astronomical Union Circular
- Pub Date:
- February 1994
- Bibcode:
- 1994IAUC.5939....1B