The F-Type Asteroid – 45 Eugenia

After a tough search in the early evening sky of 09DEC20 delayed by weeks, because of cloudy weather, we have finally located and captured images of 45 Eugenia (below).

These composite images of 45 Eugenia are made from 9 x 2″ exposures, 12,800ISO, f/10; FL2350mm/

Why is that significant?

45 Eugenia is a larger than average main-belt asteroid measuring ~216 km in diameter, and only one of two known asteroids that can boast two satellites or moons. It is now in Cetus, The Whale, which rises at 16:30-17:00 local time.

Adding to the difficulty of observing 45 Eugenia in the early evening near the horizon is its low albedo and make-up. A F-type asteroid (designating its spectral-type), it is extremely dark like soot, magnitude ~12. Its spectra exhibits carbonaceous material, and with the orbital elements of its moons now known, it can be accurately gauged to be of low density.

In 1998, at the Canada, France, Hawai`i telescope with its adaptable optical components, 45 Eugenia’s first moon were observed. It was named “Petit Prince” by its French discoverer and turned out to be 5 km in diameter. In 2004, a second moon was observed and tentatively named ” 45 S/2004″.

Petit Prince can be seen below, with 45 Eugenia at five separate locations in its orbit. The flare-like images surrounding 45 Eugenia and Petit Prince are artifacts of the adaptive optics.

45 Eugenia was discovered on 27 June 1857 by the Franco-German amateur astronomer Hermann Goldschmidt. His instrument of discovery was an 105 mm (4 inch) refractor telescope located in his 6th floor apartment above Le Procopé in the 6th arrondissement of Paris (le centre, Saint-Germain-des-Prés). It was the forty-fifth minor planet to be discovered. The preliminary orbital elements were computed by Wilhem Forster in Berlin, based on three observations in July, 1857.

“The asteroid was named by Goldschmidt after Empress Eugenia di Montijo, the wife of Napoleon III. It was the first asteroid to be definitely named after a real person, rather than a figure from classical legend.” – Wikipedia

Hermann Goldschmidt Portrait.jpg
Hermann Goldschmidt, 1850

Several lectures on astronomy were planned for the occasion of a lunar eclipse of 1847. Urbain Le Verrier, discoverer of Neptune, held one in the Sorbonne. By pure chance, Goldshmidt attended this lecture, which awakened his interest in astronomy and led him to pursue it as a career.

Goldschmidt originally bought a telescope with the diameter of 52 millimeters (2.0 in) with the money he got from selling two portraits of Galileo he painted during a stay in Firenze. Very soon he started updating the star charts he had with new stars. During this work he observed the same area several times and was able to detect variable stars and moving objects like planets. He discovered his first new planet (today classified as asteroid) on November 15, 1852.

“Goldschmidt confirmed his observations with the help of François Arago at the Paris Observatory, up the street from his flat, on November 18. Arago suggested the name Lutetium, based on the Latin name of Paris Lutetia . The discovery of the new asteroid was published on November 23.” – Wikipedia

The 105 mm refractor enabled him to discover nine asteroids between May 1857 and May 1861.

“During that period, the Academy of Science awarded Goldschmidt the astronomical prize medal several times, and he was made a Chevalier of the Légion d’honneur in 1857. By the time of his final discovery in May 1861, the Royal Astronomical Society had awarded him the Gold Medal of the Royal Astronomical Society for the discovery of 13 asteroids. At that point, the second most successful astronomers John Russell Hind and Robert Luther had each discovered 10.” – Wikipedia

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