Astronomy Picture of the Day 5-31-03

NASA ^ | 5-31-03 | Robert Nemiroff and Jerry Bonnell

[petuniasevan]

Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2003 May 31

NGC 1818: Pick A Star
Credit: R. Elson and R. Sword (IoA Cambridge), NASA

Explanation: This is NGC 1818, a youthful, glittering cluster of 20,000 stars residing in the Large Magellanic Cloud, 180,000 light-years away. Pick a star. Any star. Astronomers might pick the unassuming bluish-white one (circled) which appears to be a hot newly formed white dwarf star. What makes it so interesting? The standard astronomical wisdom suggests that stars over 5 times as massive as the sun rapidly exhaust their nuclear fuel and end their lives in a spectacular supernova explosion. With less than this critical mass they evolve into red giants, pass through a relatively peaceful planetary nebula phase, and calmly fade away as white dwarf stars like this one. Except that as a member of the NGC 1818 cluster, this new white dwarf would have evolved from a red giant star over 7.6 times as massive as the sun -- which should have exploded! Its discovery will likely force astronomers to revise the limiting mass estimate for supernovae upward.

[petuniasevan]

What's that noise I hear?

Ah, it's Dr. Chandrasekhar spinning in his grave!

Sometimes observations/conclusions are in error. Sometimes it's theory that has a glitch. One of them must be wrong!

Note that the above image is a Hubble WFPC2 image. The Wide Field Planetary Camera 2 is comprised of 4 separate cameras. One of them records a magnified image for details. This image must be resized to match the other 3 images for the final image. See this link for the illustrations and details.

Constructing The View

As I write this, locations in Alaska should be experiencing the partial solar eclipse right NOW. Hope you enjoyed it, RightWhale!

[petuniasevan]

[cardinal4]

Thanks again!

[petuniasevan]

Freeper unix has kindly volunteered to post the APOD in my absence next week (June 2-9).

Thanks to all well-wishers. I intend to get some photos (digital Mavica CD camera!) and will post some if I can get my new Fotki account to work for image sourcing.


Where am I going? Sunny Southern California for a week's visit with relatives. I grew up there.

[petuniasevan]

You're quick!

[cardinal4]

Yep. Just got off work, was checking my email before turning in when you pinged. A real treat as always! Good night!

[firewalk]

Thanks for the ping
& good morning

[headsonpikes]

What a jewel-box! Stupendous!

[Soaring Feather]

AWESOME!

[sistergoldenhair]

Thanks for the ping.