32P/Comas Solà

Lore & Background

The comet was discovered on 4 November 1926 by Josep Comas Solà while he was taking photographs with a 6-inch (150 mm) telescope as part of his work on asteroids for the Fabra Observatory. At the time, its position was located within the constellation Cetus. Early on, several astronomers suggested that the comet might be a return of the then lost periodic comet 113P/Spitaler. In 1935, additional positions had been obtained, and P. Ramensky investigated the orbital motion back to 1911. He noted the comet passed very close to Jupiter during May 1912 and that, prior to this approach, the comet had a perihelion distance of 2.15 AU (322 million km) and an orbital period of 9.43 years. The identity with Comet Spitaler was thus disproven.

In 1933, Danish astronomer Julie Vinter Hansen undertook significant new research which calculated the orbit of the comet up to 1980, predicting when it would return to the Earth's orbit. While searching for 32P/Comas Solà in 1969, two Soviet astronomers Klim Churyumov and Svetlana Gerasimenko accidentally discovered a new comet in photographic plates they took, which is now known as 67P/Churyumov–Gerasimenko.

Physical characteristics of the nucleus have been estimated multiple times. In 1985, precession models derived an equatorial radius between 0.99–1.15 km (0.62–0.71 mi). CCD photometry taken while the comet was 3.1 AU from the Sun in 1999 obtained a larger upper limit of about 3.2 km (2.0 mi). Further studies in 2006 revised the size estimate to about 2.52 km (1.57 mi). Initial estimates of the rotation period indicated the comet spins once every 1.5 to 2.3 days, but forced precession models obtained in 2001 indicated a shorter rotation period of around 7.3 hours.

Reader's Guide

32P/Comas Solà holds significance as the second comet discovered by Josep Comas Solà, a Spanish astronomer whose work at the Fabra Observatory contributed to early 20th-century comet and asteroid studies. Its observational history includes a notable early confusion with the lost periodic comet 113P/Spitaler, which was resolved through orbital calculations by P. Ramensky showing a close Jupiter approach in 1912 that altered the comet's orbit. The comet also played an indirect role in the discovery of 67P/Churyumov–Gerasimenko, as two Soviet astronomers searching for 32P/Comas Solà in 1969 instead found that now-famous comet. Danish astronomer Julie Vinter Hansen's 1933 orbital calculations, predicting returns up to 1980, represent an important early computational effort for a periodic comet. The comet's nucleus size estimates have evolved over decades, from precession models in 1985 to CCD photometry in 1999 and a revised figure in 2006, illustrating the challenges of measuring small, distant cometary bodies. Its rotation period also remains subject to revision, with early estimates of 1.5–2.3 days later refined to about 7.3 hours based on forced precession models.

Did You Know?

• The comet was discovered on 4 November 1926 by Josep Comas Solà using a 6-inch telescope at the Fabra Observatory.
• In 1933, Danish astronomer Julie Vinter Hansen calculated the comet's orbit up to 1980, predicting its returns to Earth's orbit.
• The comet's nucleus size was revised to about 2.52 km in 2006, after earlier estimates ranged from 0.99 km to 3.2 km.

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