A GEM FOR THE KING
Image Credit & Copyright: Davide De Martin. CLICK image for larger view and look below for information and related links.
Located 2500 light years away in the circumpolar constellation Cepheus, the “King of Aethiopia” is this gem of the night sky known as IC1396. This HII star forming region spans three degrees on the night sky (That’s 6 full moons wide!) and is being ionized by the massive O-type star HD 206267 which is actually a triple star system near its center. One of the stars orbits the larger star every 3.7 days while the third component is not yet confirmed as a member of the system. HD 206267 is also a member of the open star cluster Trumpler 37 which gives this star an age of about 3 million years old.
As with most star forming regions similar to this the entirety of this object is mainly created by the star at its center. Ever since the star came to life its radiation/stellar winds have been hard at work carving out and illuminating this cavern that we see in the image. If you look closely you can see numerous Bok & Cometary globules throughout the structure where the stellar emissions have met pockets of gas and dust much thicker than what’s found in the rest of the nebula. This is because within many of these thick filaments other stars are near birth as well and these regions are much denser due to gravity and compression. Have some patience……..let’s take this ship to one of those in the next post!
Also, the bright orange/red star at the bottom of this object is HD 206936 Mu Cephei or “Erakis.” William Herschel named it “The Garnet Star” and it has subsequently known for some time as Herschel’s Garnet Star. It’s a near-death runaway red supergiant and one of the largest and most luminous stars in the entire galaxy. It’s so large that you could stuff it with about one billion suns as it is about 1000 times larger and its brightness is about 100,000 times that of the Sun. This active star is also the prototype for the Mu Cephei Variable star class whose brightness varies from +3.62 to +5 over a 2.5 year period. If you have a go-to mount for your telescope you can find this star at SAO 33693 or RA 21h 43m 30.4609s / DEC +58° 46′ 48.166″.
NAME: IC 1396.
WHAT IS IT?: HII star forming region illuminated by O-type star HD 206267.
HOW BIG IS IT?: Approximately 3 degrees of the night sky.
HOW FAR AWAY IS IT?: Approximately 2500 light years.
APPARENT MAGNITUDE: Central Star HD206267 is 5.62 or +5.62.
WHERE IS IT? (General): Constellation Cepheus “The King of Aethiopia.”
WHERE IS IT? (Exact RA/DEC J2000): RA 21h 38m 57.70s / DEC +57° 29′ 21.0″.
Davide De Martin page for this image: http://www.skyfactory.org/ic1396/index.php
NASA APOD page for this image: http://apod.nasa.gov/apod/ap050908.html
SIMBAD data page for star HD 206267: http://simbad.u-strasbg.fr/simbad/sim-id?Ident=HD+206267