The Occultation of a R=14.6 (Combined) Star by Trojan Asteroid Antilochus

Friday May 10, 2024 at 8:54:50pm PDT

OW cloud prediction page

 

This is a high value Trojan asteroid event, and the faint star is makes it most suitable for getting observations from MIRA's 36" at Chews Ridge. The 36" is on the centerline, with 80% odds of getting the occultation and refning the orbit of this asteroid. It happens on a Friday evening, which also makes it ideal for an expedition from the Cabrillo Astronomy Occultation team. However, it will be difficult to get ready as the event happens in twilight with the sun at altitude -10.4 degrees. It will require fast target acquisition and focusing. Fortunately the 36" is a permanent scope with high pointing accuracy not needing the usual 2-point alignment the 8SE scopes need. However, rapid focusing will be critical. Perhaps done on a bright star early in twilight?

To remind - these Trojan asteroid so far have no close up images, and their origin and evolution are a matter of speculation, with too little data to guide the ideas. Are they mostly fragments from broken larger asteroids, as describes perhaps many in the main belt? Are they instead weak conglomerations of pebbles and dust that might dominate the orbit of Jupiter instead? There's already evidence of irregular shape to Eurybates - prime goal of the LUCY Mission on it's way to the Trojans now - thanks to a recent occultation.

 

   

Results:

Kirk and I tested the observability of this event at the event time at sun altitude -10.4 and at the sun elongation of this event (it was in the SW, so that further made it tough) on the night before; May 9. Clear skies in Santa Cruz. At the time of the event the next night, sun at -10.4, an integration of 4x at that sun elongation was do-able, but bright sky. The target was invisible at 4x. Even at 16x 15 minutes later, when the sky brightness was able to handle 16x but not 32x, the target was still invisible. Not do-able. I estimate the drive to get to dark enough skies would require the middle of Nevada to have a chance. Not going to happen, for this one.