RADAR OBSERVATIONS OF COMET 103P/HARTLEY 2
- Arecibo Observatory, National Astronomy and Ionosphere Center, HC3 Box 53995, Arecibo, Puerto Rico 00612 (Puerto Rico)
Comets rarely come close enough to be studied intensively with Earth-based radar. The most recent such occurrence was when Comet 103P/Hartley 2 passed within 0.12 AU in late 2010 October, less than two weeks before the EPOXI flyby. This offered a unique opportunity to improve pre-encounter trajectory knowledge and obtain complementary physical data for a spacecraft-targeted comet. 103P/Hartley 2 is only the fourth comet nucleus to be imaged with radar and already the second to be identified as an elongated, bilobate object based on its delay-Doppler signature. The images show the dominant spin mode to be a rotation about the short axis with a period of 18.2 hr. The nucleus has a low radar albedo consistent with a surface density of 0.5-1.0 g cm{sup -3}. A separate echo component was detected from large (>cm) grains ejected anisotropically with velocities of several to tens of meters per second. Radar shows that, in terms of large-grain production, 103P/Hartley 2 is an unusually active comet for its size.
- OSTI ID:
- 21562621
- Journal Information:
- Astrophysical Journal Letters, Vol. 734, Issue 1; Other Information: DOI: 10.1088/2041-8205/734/1/L2; ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
Similar Records
Hyperactivity and Dust Composition of Comet 103P/Hartley 2 During the EPOXI Encounter
WATER PRODUCTION BY COMET 103P/HARTLEY 2 OBSERVED WITH THE SWAN INSTRUMENT ON THE SOHO SPACECRAFT