Radio continuum observations of Comet P/Halley at 250 GHz
Abstract
The detection of continuum radio emission from comet Halley has been confirmed using a He-3 cooled bolometer at a frequency of 250 GHz. The radiation, normalized to a geocentric and heliocentric distance of 0.66 and 1.58 AU, respectively, is probably not correlated with the 2.2-day or the 7.4-day nucleus rotation periods. The normalized emission is steady, with a mean flux density of 51.6 + or - 5.2 mJy over the postperihelion observing period of 8 days (March 1986). This is comparable to the value determined several months earlier (November 1985). The error limits include the uncertainty of the absolute calibration. The derived photometric diameter is 35 km. The bulk of the emission seems to come from centimeter-sized particles within a sphere of diameter 3800 km centered on the nucleus. The steady emission over months may indicate that the larger particles remain a long time near the nucleus.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- September 1989
- Bibcode:
- 1989A&A...222..323A
- Keywords:
-
- Comet Nuclei;
- Halley'S Comet;
- Helium Isotopes;
- Radio Observation;
- Black Body Radiation;
- Giotto Mission;
- Grain Size;
- Radio Waves;
- COMETS;
- HALLEY;
- RADIO WAVES;
- EMISSIONS;
- EARTH-BASED OBSERVATIONS;
- FLUX;
- ASTRONOMY;
- RADIATION;
- DENSITY;
- COMET NUCLEI;
- PARTICLES;
- COMPARISONS;
- TIMESCALE;
- SIZE;
- DIAMETER;
- PHOTOMETRY;
- COMAE;
- GRAINS;
- Astrophysics; Comets