C/2002 O5 (NEAT) was discovered on images taken with the 1.2-m Schmidt at Haleakala in Hawaii on July 30th. It was magnitude 17 anad had a small coma of 6" diameter and a tail 12" long. The orbit appeared from early MPC solutions to be of exceptionally short period (4.87 years). As the orbit was refined the period increased slightly, but the "definitive" value of 4.98 years from 240 observations between July 30th and September 9th is still one of the shortest known.
This is a very faint, low activity comet that has been discovered at a very favourable approach to the Earth. The absolute magnitude of 18.0 is one of the very faintest known.
Perihelion occurred at 1.17AU on August 3rd 2002.
The light curve
The light curve is based on CCD observations in a 10" aperture (m2) and CCD total magnitude estimates in a 18" aperture, both in the R band. The comet is fading rapidly as it receeds from perihelion and moves away from the Earth at the same time.
Observations by:
2007-08-12 Tenemos una gran cantidad de observaciones de muchos observadores (213, 442, A06, A79, B20, J47, J51, J53 y J59). La curva de luz muestra que el cometa se está debilitando progresivamente (ver image003.gif), aunque en parte eso se debe al hecho que se ha estado alejando de la Tierra. El cometa ya ha pasado por el perihelio. En 2002 teníamos pocas observaciones (de 213 y 442), todas después del perihelio. Lo que es interesante es que los datos muestran un fuerte declive en actividad desde las primeras observaciones 10 días antes del perihelio. Aunque no hay datos suficientes para ver el patrón de 2002, las observaciones se sobreponen en las de 2007 (ver image001.gif) sugiriendo que el cometa tiene una curva de luz fuertemente asimétrica con su máximo antes del perihelio. La fotometría multiapertura muestra que este cometa tiene una coma inusualmente extendida. El valor de Afrho en una apertura de 20” es aproximadamente un 40% mayor que en una apertura de 10” (ver image005.gif).