Constraints on the Diameter and Albedo of 2060 Chiron
Abstract
Asteroid 2060 Chiron is the largest known object exhibiting cometary activity. Radiometric observations made in 1983 from a ground-based telescope and the Infrared Astronomical Satellite are osed to examine the limits on Chiron's diameter and albedo. It is argued that Chiron's surface temperature distribution at that time is best described by an "isothermal latitude" or "rapid-rotator" model. Consequently, Chiron has a maximum diameter of 372 kilometers and a minimum geometric albedo of 2.7%. This is much bigger and darker than previous estimates, and suggests that gravity may play a significant role in the evolution of gas and dust emissions. It is also found that for large obliquities, surface temperatures can vary dramatically on time scales of a decade, and that such geometry may play a critical role in explaining Chiron's observed photometric behavior since its discovery in 1977.
- Publication:
-
Science
- Pub Date:
- February 1991
- DOI:
- 10.1126/science.251.4995.777
- Bibcode:
- 1991Sci...251..777S
- Keywords:
-
- Albedo;
- Astronomical Photometry;
- Chiron;
- Infrared Astronomy Satellite;
- Astronomical Models;
- Comets;
- Gravitational Fields;
- Surface Temperature;
- Telescopes;
- Lunar and Planetary Exploration; Asteroids; Comets;
- ASTEROIDS;
- CHIRON;
- DIAMETER;
- SIZE;
- ALBEDO;
- RADIOMETRY;
- SURFACE;
- DUST;
- EARTH-BASED OBSERVATIONS;
- TEMPERATURE;
- GASES;
- EMISSIONS;
- WAVELENGTHS;
- GEOMETRY;
- MODELS;
- PARAMETERS;
- OBLIQUITY;
- GRAVITY EFFECTS;
- PHOTOMETRY;
- SATELLITE OBSERVATIONS;
- IRAS SATELLITE;
- THERMAL PROPERTIES;
- INFRARED;
- ESCAPE