Sunday, December 18, 2005

Asterism in Auriga: Cheshire Cat


I decided to write up the details for an asterism I discovered in Auriga back on November 7th 2002.

Discovery details appear at the end of this post.

‘Click for more ...’ below to view two charts. The first is a wide field chart and the second is a close up of the ‘Cheshire Cat’ asterism.

Next time you're out give this asterism a shot. When Auriga is rising the image of the face is upright. Most binoculars will show this object at its best.

Click on the images to see larger views including details:

Location of ‘Cheshire Cat’ — 2° circle.

Close up of ‘Cheshire Cat’ — 2° circle.

This is my first astronomical discovery albeit a minor one but one I'm happy to have made. It is an asterism in the constellation Auriga which resembles a smiling face. I named it ‘Cheshire Cat’ on November 7th, 2002.

Here is the original text from a message #13510 on the Yahoo! Groups list ‘StarryNights’:

Date: Fri Nov 8, 2002 11:57 am
Subject: Asterism in Auriga [7Nov2002]

Last night while looking through Auriga for M36 and M38 with 8.5x42 binoculars I came across a binocular asterism located SSW of M38. It is centered on RA 5h 27.5m / Dec +35 degrees. I viewed it at ~10p EST. The object is made up of 8 stars ranging in magnitude from 5.08 (phi Aur) to 6.86 (TYC 2411-515-1). The entire asterism can fit inside a 2° circle. This asterism looks like a face -- 2 eyes (mags 6.15 & 6.52) and 6 stars for the mouth. I am calling it "Cheshire Cat" ... unless, of course, there is another Cheshire Cat up there. If so then I would call it Frog Face keeping with the alliterative theme. The face is oriented "properly" at this time of night/year.

If this asterism has been named already please let me know if the details exist somewhere.

Also, on the left edge of the "smile" (nearer to M38) is the eclipsing binary star LY Aurigae which varies from 6.7 - 7.4 with a period of 4.002 days.

Let me know what you think.

Ben Cacace
Manhattan, NYC

P.S. - with the binoculars M36 was an easy target. M38 was not an obvious open cluster.