Copyright © 1996 by Near Earth Asteroid Tracking (NEAT)
This image is a combination of two images obtained by the Near Earth Asteroid Tracking (NEAT) program using the 48-inch Oschin telescope and a CCD camera on June 12.39 and June 12.41. Each image was exposed for about 18 seconds.
Albert G. Wilson and Robert G. Harrington (Palomar Observatory, California, USA) discovered this comet in Pegasus on a photographic plate exposed with the 122-cm Schmidt on 1949 November 19.13. They estimated the magnitude as 16 and said the tail was less than 1° long. Only two additional photographic observations were obtained. These were also by Wilson and Harrington and were obtained on November 22.16 and November 25.13. The magnitude on the former date was estimated as 12.
Eleanor Helin (Palomar Observatory) discovered a fast-moving asteroidal object in Pisces on plates exposed with the 0.46-m Schmidt telescope on 1979 November 15.17 and 15.43. She confirmed the object on the 16th and estimated the magnitude as 11. It received the designation of 1979 VA.
Leland E. Cunningham (Student's Observatory, Berkeley, California, USA) said the plates exposed on 1949 November 19 and 22, showed a small, faint tail, but no trace of a coma and "would likely have been called a minor planet" had a slower telescope been used to expose the plates.
He used the three available positions to determine an elliptical orbit with a perihelion date of 1949 October 13.17, and an orbital period of 2.31 years. He added that the orbital period was "uncertain by two years or more." The comet remained lost because of the uncertainty of the orbit.
The first orbit for minor planet 1979 VA indicated a period of 4.77 years, but this was later revised to 4.29 years after observations had continued for more than a month. This latter period proved correct when the minor planet was recovered in late 1988. It then received the permanent designation of minor planet 4015.
During 1992 E. Bowell (Lowell Observatory, Arizona, USA) was in the process of searching for prediscovery images of minor planets on Palomar Sky Survey plates when he identified images of minor planet 4015 exposed on 1949 November 19, which showed a tail. Upon mentioning this to the Central Bureau for Astronomical Telegrams, Brian G. Marsden pointed out that the 1949 object was already known as comet Wilson-Harrington, thus making the comet and minor planet the same object. Marsden then successfully linked all the apparitions from 1949 to 1992.
Although the tail was definitely confirmed on the 1949 exposures, both in 1949 and during the 1992 re-investigation, close examination of images of the comet during the 1979-80, 1988-89, and 1992 apparitions revealed strictly stellar images. Marsden noted, "the observations suggest that the object is a largely inactive comet that undergoes occasional outburst."
The comet next returned to perihelion in 1996 and in 2001. Few brightness estimates were made at either apparition, but the brightest estimate of 1996-1997 was 18.6, while in 2001-2002 it was about 20.
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