Looking Up: Khan-Gratulations Are In Order...

Nov 5, 2018

What might appear to be 'space seeds' blooming are in fact planetary nebulas. A planetary nebula represents a phase of stellar evolution that our sun should experience several billion years from now.
Credit X-ray: NASA/CXC/RIT/J.Kastner et al.; Optical: NASA/STScI / nasa.gov

To the star Menkar, which, as we learn on this week's episode of Looking Up, is well on its way to becoming a planetary nebula.

With the end of daylight savings time, the nights come early to southern Colorado. And while that make it tough to get a round of golf in after work, it makes it easier to look up at the many cool things in the Colorado night sky. And one of the coolest, literally, is the very interesting star Menkar.

Menkar is the second-brightest star in the constellation Cetus the Whale, high in our sky right now. At magnitude 2.5, it’s not blazing out there, but it is bright enough to see from your front yard. Menkar is interesting in several ways. First, it’s dying. An old and giant star about 85 times bigger than our Sun, Menkar has used up much of its fuel. It’s becoming unstable, fluctuating in brightness significantly, as it prepares for the end, when it will blast off the outer layers of the star to form what is misleadingly called a Planetary Nebula – a throwback to when early astronomers saw the puffy cloud of expanding gas from such stars and thought they looked like planets.

Menkar is also another name – one that might ring a bell if you are a science fiction fan – Ceti Alpha. If you recall the second Star Trek movie, the Wrath of Khan, you may remember that Khan and his crew were marooned on Ceti Alpha 5, the theoretical fifth planet of Menkar! So, look up at the night sky and yell KHAN!!

If you’d like to take a closer look Menkar, or any of the other wonderful and amazing things in the sky, please visit csastro.org for a link to information on our monthly meetings and our free public star parties.