November 04 – Asteroid 91 Aegina

Asteroid 91 Aegina was the second and last asteroid to be discovered by Édouard Jean-Marie Stephan, just three months after his first (89 Julia).  It was discovered on November 4th 1866, and is a large, dark, 109 km wide, C-type main-belter.   Monsieur Stephan is now best remembered for the discovery of the compact galaxy group known as Stephan’s Quintet.

Aegina’s name refers, unsurprisingly, to a nymph from Greek mythology, one of dozens, possibly hundreds, giving their names to heavenly bodies (this one is also today a small island near Athens).

"Aegina Visited by Jupiter " (Jean Baptiste Greuze)
“Aegina Visited by Jupiter ” (Jean Baptiste Greuze)

Aegina, again unsurprisingly, was one of Zeus’ many conquests.  She is known to have had two children: one, the mortal Menoetius,  son of Actor, became king of Opus, and fathered Patroclus (Achilles‘ cousin); the other, Aecus, was the result of Aegina being whisked off by Zeus (in the form of an eagle) to the small island I mentioned earlier.

Today’s second discovery, from 1875, is the even larger 187 km diameter asteroid 154 Bertha (another C-type main belt member).  It is one of the fourteen asteroids discovered by the Henry brothers, Paul and Prosper, credited to each alternately.  This time, it was Prosper’s turn.  It is believed the name may refer to Berthe Martin-Flammarion, sister of the astronomer and science fiction author Nicolas Camille Flammarion.

Asteroid 2867 Šteins was discovered today in 1969 by Nikolay Stepanovich Chernykh.  I have no idea how many asteroids he discovered, but it’s somewhere in the region of 500.  Šteins gets a mention today because it was the subject of a flyby by the Rosetta probe, which gives us a better photo-opportunity than normal for an asteroid.

Asteroid Steins viewed by Rosetta (image credit: ESA)
Asteroid Steins viewed by Rosetta (image credit: ESA)

This particular fuzzy shape is named after the Latvian astronomer Kārlis Šteins, and measures just under 7 km across at the widest point.