How to find the tornado-shaped open cluster NGC 663, the barred spiral galaxy NGC 1365 & the unusual variable star, AE Aurigae the weekend of December 27-29, 2013.
Friday, December 27 - Born today in 1571 was Johannes Kepler - Danish astronomer and assistant to Tycho Brahe. Kepler used Brahe's copious notes of Mars' positions to help formulate his three laws of planetary motion. These laws are still in use today.
Now let's travel 398 light-years away as we have a look at AR Aurigae - the centermost star in a brilliant collection. It is about one-third the distance from southern Beta to northern Alpha (Capella). AR is an eclipsing binary which consists of two main sequence white dwarf stars. About every 4.1 days, this pair will make a slight magnitude drop. While both are chemically peculiar, neither fills its Roche Lobe - meaning they are not stripping material from each other to cause these unusual abundances. Recent studies have shown the possibility of a third, unseen companion! But even binoculars will see that AR resides in a great field of stars and is worth a little of your time.
NGC 663 - Palomar Observatory Courtesy of Caltech
When you're ready, let's turn our attention towards a very beautiful and lesser known open cluster - NGC 663 (Right Ascension: 1:46.0 - Declination: +61:15). You'll find it about one fingerwidth northeast of Delta Cassiopeiae... This magnificent tornado-shaped collection of stars will be quite noticeable in binoculars and will resolve out more than a dozen members to a small telescope. Larger telescopes will fully resolve this magnitude 7 cluster and reveal color amongst its many stars.
Saturday, December 28 -Today we celebrate the birth of Arthur S. Eddington. Born in 1882, Eddington was a British theoretical astrophysicist whose work was fundamental to interpreting and explaining stellar nature. He also coined the phrase "expanding universe" to refer to the mutual recession of the galaxies.
Galaxies? You asked for galaxies? Then let's go haunt the Fornax Galaxy Cluster! Containing around 20 galaxies brighter than 13th magnitude in a one degree field, here is where a galaxy hunter's paradise begins! About a degree and a half north of Tau Fornacis is the large, bright and round spiral NGC 1398 (Right Ascension: 3:38.9 - Declination: -26:20). A little more than a degree west-northwest is the easy ring of the planetary nebula NGC 1360. Look for the concentrated core and dark dustlane of NGC 1371 a degree north-northeast - or the round NGC 1385 which accompanies it. Why not visit Bennett 10 or Caldwell 67 as we take a look at NGC 1097 (Right Ascension: 2:46.3 - Declination: -30:17) about 6 degrees west-southwest of Alpha? This one is bright enough to be caught with binoculars!
NGC 1365 - Palomar Observatory Courtesy of Caltech
Telescopes will love NGC 1365 (Right Ascension: 3:33.6 - Declination: -36:08) at the heart of the cluster proper. This great barred spiral gives an awesome view in even the smallest of scopes. As you slide north, you will encounter a host of galaxies, NGCs 1386, 1389, 1404, 1387, 1399, 1379, 1374, 1381 and 1380. There are galaxies everywhere! But, if you lose track? Remember the brightest of these are two ellipticals - 1399 and 1404. Have fun!
Sunday, December 29 - Tonight let's go to our maps and head west of M36 and M38 to identify AE Aurigae. As an unusual variable, AE is normally around 6th magnitude and resides approximately 1600 light-years distant. The beauty in this region is not particularly the star itself but the faint nebula in which it resides. Known as IC 405 (Right Ascension: 5:16.2 - Declination: +34:16), this is an area of mostly dust and very little gas. What makes this view so entertaining is that we are looking at a "runaway" star.
AE Aurigae - Palomar Observatory Courtesy of Caltech
It is believed that AE originated in the M42 region in Orion. Cruising along at a very respectable speed of 130 kilometers per second, AE flew the "stellar nest" some 2.7 million years ago! Although IC 405 is not directly related to AE, there is evidence within the nebula that areas have been cleared of their dust by the rapid northward motion of the star. AE's hot, blue illumination and high energy photons fuel what little gas is contained within the region, and its light reflects off the surrounding dust as well. Although we cannot "see" with our eyes like a photograph, together this pair makes an outstanding view for the small backyard telescope. It is known as "The Flaming Star."
Until next year? Dreams really do come true when you keep on reaching for the stars!
About Tammy Plotner - Tammy is a professional astronomy author, President Emeritus of Warren Rupp Observatory and retired Astronomical League Executive Secretary. She's received a vast number of astronomy achievement and observing awards, including the Great Lakes Astronomy Achievement Award, RG Wright Service Award and the first woman astronomer to achieve Comet Hunter's Gold Status.