January 04 – Asteroid 86 Semele

Making his first and last appearance in the field of asteroid discovery today is German astronomer Friedrich Tietjen.  On January 4th 1866, from the New Berlin Observatory (the place where Neptune was discovered) he found asteroid 86 Semelea large, dark, C-type body of about 120 km wide, in the main belt.

Aphelion 3.761 AU
Perihelion 2.467 AU
Semi-Major Axis 3.114 AU
Orbital Period 5.5 years
Inclination 4.822°
Eccentricity 0.208

Semele is named after the daughter of Cadmus and Harmonia (asteroid 40).  She was the mother of Dionysus.  Zeus was the father, as usual (where did he find the time?).

Jove and Semele (S Ricci)

Jove and Semele (S Ricci)

Today’s picture is of Jove and Semele, by the Italian artist Sebastiano Ricci, a man whose private life would not have shocked the average Greek or Roman god.  He was imprisoned at a young age when, in an attempt to avoid marriage, he tried to poison a young woman he had made pregnant.  He did eventually marry her, but I doubt there was much trust in the relationship.


1797  –  Birth of Wilhelm Beer, moon mapper and accurate predictor of the rotation of Mars (only about a tenth of  a second away from today’s value).


1876  –  158 Koronisa 35.4 km diameter S-type main belt asteroid, discovered by Russian astronomer Viktor Knorre.  Koronis is the head of the Koronidian asteroid family, created from a collision about 15 million years ago.  No known member of the family is particularly large (the biggest, 28 Lacrimosa, is only about 41 km across), but there are a lot of them, with over 300 known members.


1908  –  Discovery of asteroid 654 Zelinda by August Kopff, from the Heidelberg-Königstuhl State Observatory in Germany.  Zelinda is in the main belt, and measures somewhere in the region of 130 km across (opinions vary).  Zelinda was named by the Italian astronomer Elia Millosevich, in honour of the daughter (again, opinions vary, with The Dictionary of Minor Planet Names saying she was his sister, but she was thirty years younger than him, so I’m going with daughter) of mathematician and politician Ulisse Dini (a friend of Millosevich).


2010  –  Exoplanet Kepler-7b, a “hot Jupiter”, discovered by NASA’s Kepler spacecraft.  The planet was recently found to have a surprisingly predictable weather.


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