Heavenly Skies: Gaze up at Cepheus the KingBy: Jason Brand, Special to Gold Country News Service
Cepheus (SEE-fee-uhs) was the King of ancient Ethiopia, a region in the area of modern Israel, Jordan and Egypt which differs from the modern country of Ethiopia located on the Horn of Africa.
Cepheus’ rule came to an abrupt end when his daughter demanded to marry Perseus rather than another suitor, Phineus.
Phineus demanded Andromeda marry him as promised by King Cepheus and challenged Perseus to a fight. Realizing he’s losing the fight, Perseus pulled the severed head of Medusa from his sack, showed it to Phineus and turned him to stone.
Queen Cassiopeia and King Cepheus also caught a glimpse of Medusa’s eyes by accident and the royal couple turned to stone as well. Poseidon, favoring the king, put him forever in the sky with his foot just above the pole star, Polaris.
The shape of the constellation Cepheus is reminiscent of a pointed-roofed house drawn by a child. In early winter nights, you will find Cepheus overhead, above Polaris, the North Star, and to the left of Cassiopeia. Alternatively, look for Cygnus the Swan, drawing a line from its tail star (Deneb) to Polaris. At the center of that line you should find the right shoulder star (Alderamin) of Cepheus. The stars of Cepheus are not bright, so a dark night might be required to see him for the first time. When you visit the observatory, just ask a docent to point him out to you during your visit.
While not many objects are easily viewable within Cepheus through the observatory’s telescopes, what is lost in quantity is made up in quality. First recorded by William Hershel in November 1788, the oval shaped Bow Tie Nebula or NGC40, is a 1.7 light year wide planetary nebula. Nearly 2,700 light-years away, the oval we see is comprises gas that once made up the atmosphere of its progenitor star, whose Earth-sized core (now categorized as a white dwarf) remains hot. How hot? Estimates of the surface temperature are around 50,000 Celsius and the surrounding gas is near 10,000 Celsius. Come see it now as it will fade away over the next 30,000 years.
The Garnet Star, Mu Cephei, can be found near the bottom of the house-shaped constellation. This red super giant star is perhaps my favorite to view and offers a dramatic reddish-orange hue as seen through the eyepiece. It is one of the brightest stars known in the Milky Way Galaxy. To the naked eye, we do not perceive it as such a bright star since it is somewhere between 2,500 and 5,500 light years away. Estimated to be 20 times more massive than our sun, this star’s orange-red color is a result of its fusing large amounts of helium into carbon. Its physical size would put its atmospheric surface between the orbits of Jupiter and Saturn if placed at the center of our solar system. It is so large it could hold 1 billion suns and its luminosity (brightness) equivalent to 350,000 suns. Measured apparent brightness, which is variable over time, swings from +3.63 (brighter) to +5.0 (dimmer) over 2.5 years. The Garnet Star is in its last throws of life, losing mass through stellar winds and if the theories hold true, we might see it supernova in the next million years. Mark your calendar.
Looking for a gem to give as a Christmas gift? Bring a friend down to the Community observatory for a night and show them the Garnet Star and a few other objects in the night sky. Jupiter is up with its Galilean moons for all to see. You might even spy Jupiter’s moon Io, the mother of King Cepheus. For information regarding location and current visiting hours, go to www.communityobservatory.com and “like” the Community Observatory on Facebook.
Jason Brand is lead docent with the Cameron Park Rotary Club Community Observatory in Placerville.