Periodic Comet Brorsen-Metcalf (1989o)
Abstract
D. G. Schleicher, D. J. Osip, and R. L. Millis, Lowell Observatory, communicate: "We report gas production rates from aperture photometry obtained on July 7.43 UT, using the Lowell 1.07-m telescope: log Q(OH) = 27.8, log Q(CN) = 25.4, log Q(C2) = 25.3, log Q(C3) = 24.2, log Q(NH) = 25.0. The gas-to-dust ratio is high, with log Q(OH)/(A f rho) = 26.2 (cf. A'Hearn et al. 1984, A.J. 89, 579). Continuum magnitude at 485 nm within a 75"- diameter aperture is about 14.0. The comet is extremely diffuse, presumably due to the low concentration of dust." R. M. Wagner, R. Bertram, and J. Beaver, Ohio State University; and D. G. Schleicher and B. L. Lutz, Lowell Observatory, report: "Long-slit spectra were obtained on July 7.44 UT using the OSU CCD Spectrograph (spectral range 360-620 nm, resolution 0.8 nm) on the Perkins 1.8-m reflector at Lowell Observatory. Strong molecular emissions of CN, C3, CH, C2, and NH2 were present, superposed on a very weak continuum. CN (Delta v=0) and C2 (Delta v=0) emission extended for at least 5' along the projected length of the slit." H. Spinrad reports that spectra obtained by M. Dickinson, R. Dey, and himself with the low-resolution spectrograph (range 390-800 nm) on the 3-m Shane reflector at the Lick Observatory on July 7.47 UT show strong C2 and O I and detectable C3 and CN emission. The continuum was moderately weak. Total visual magnitude estimates: July 8.45 UT, 9.6 (C. S. Morris, Pine Mountain Club, CA, 20x80 binoculars; 9' coma); 10.76, 9.0 (D. A. J. Seargent, The Entrance, N.S.W., 0.15-m reflector); 12.30, 7.8 (D. W. E. Green, Harvard, MA, 7x50 binoculars; 12' coma); 13.32, 8.1 (J. E. Bortle, Stormville, NY, 10x50 binoculars; 10' coma).
- Publication:
-
International Astronomical Union Circular
- Pub Date:
- July 1989
- Bibcode:
- 1989IAUC.4810....1S