Sunday, February 17, 2008

Both components of double asteroid (90) Antiope occulted a star

Success in Japan: When the well-known double asteroid (90) Antiope occulted a star on Jan. 2, one observer caught the main component passing in front of it while quite a number of video observers recorded an occultation by component B. Many more observers didn't see the star wink out, but this is also of some importance as the first analysis of the observations in CBET #1263 of today shows: The best-fit ellipse to the observed chords of the occultation by component B has dimensions of 89±4 x 82±1 km. As there was only one chord observed for component A, the diameter of that body cannot be determined from the occultation. However, two specific 'miss' observations constrain its location and size which is about the same as B's.

In other news an analysis of the lightcurve of 17P/Holmes reveals a fading with 5 log r (r being the istance from the Sun): "That is, the comet became fainter only because the distance increased. The dust shell itself did not fade at all, just it became somewhat more distant. The formula suggests that the comet will keep so bright as 6 mag in the next autumn and winter." Here is a nice view of the LBT at night, Ed Hubble will get a U.S. stamp this year - and this blogger has become aware of a remarkable 'Armageddon' parody, a 30-minute animation feature film created by a 20-year old.

Last night presented the perfect opportunity in Europe to draw or photograph a lunar illumination phenomenon known as "the jewelled handle" (or "der goldene Henkel" in German). The star Mira is still bright - as is the (in-)famous satellite USA 193 which was just seen at 1st mag. tonight and which is feeling the drag of the atmosphere. The astronauts currently in orbit are not worried by its upcoming fate, we've learned more about hydrazine and the debate about the DoD's 'true' motives goes on ...

1 comment:

Daniel Fischer said...

Results from Japanese occultation campaigns can be found here.