Astronomy and Astrophysics – Astronomy
Scientific paper
Jan 1992
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1992phdt........10l&link_type=abstract
Ph.D. Thesis Maryland Univ., College Park.
Astronomy and Astrophysics
Astronomy
15
Austin Comet, Comet Tails, Infrared Astronomy, Infrared Radiation, Okazaki-Levy-Rudenko Comet, Schwassmann-Wachmann Comet, Zodiacal Dust, Cosmic Background Explorer Satellite, Infrared Photometry, Infrared Spectra, Particle Size Distribution
Scientific paper
The COBE/Diffuse Infrared Background Experiment (DIRBE) is a 0.7 degree x 0.7 degree broadband absolute photometer covering the wavelength range 1 to 240 micrometers. During its November 1989-September 1990 all-sky survey, DIRBE detected the comets C/Okazaki-Levy-Rudenko (C/OLR), C/Austin, P/ Schwassmann-Wachmann 3 (P/SW-3), and C/Levy, providing unique near to far infrared photometry and large-scale images for these comets. The observations of C/Austin were the most detailed, as the comet exhibited an approximately 7 degree long, highly structured dust tail at 12 and 25 micrometers. The lack of a similar visible tail, the results of dynamical modeling of the tail morphology, and the near-greybody behavior of the observed spectra suggest a dust particle surface area distribution dominated by large particles. Compared to visible estimates, a relatively large dust mass loss rate is found for C/Austin. C/OLR and C/Levy were detected only as line sources extended approximately 2 degrees in the antisolar direction, but exhibited interesting infrared spectra. The spectra of C/OLR were very similar to C/Austin. The spectra of C/Levy were very different, exhibiting an elevated color temperature, a fall-off in grain emissivity at long wavelength, and a particle size distribution dominated by small particles. Interestingly, C/Levy was the only one of the four comets found by other observers to have a pronounced light curve and significant activity. P/SW-3 was detected only as a low S/N point source. The mere detection of the comet is interesting, as four other visibly brighter comets were not detected by DIRBE. This suggests an enhancement of the infrared flux of this comet, possibly due to the presence of a dust trail. Comparison of the DIRBE data for these comets suggests that the observed differences are due to particle size effects, not compositional variations. Cometary dust emission is found to be an important source of the zodiacal cloud if the mass emission rate for C/Austin is typical for all gassy comets. The estimated lower limit for the dust/gas ratio of these comets is 0.1 to 0.5.
No associations
LandOfFree
Infrared observations of cometary dust by COBE does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Infrared observations of cometary dust by COBE, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Infrared observations of cometary dust by COBE will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-939688