Oct 11th: Raiders of the Lost Stars

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Podcaster: Richard Drumm
Title:
Space Scoop: Raiders of the Lost Stars

Organization:365 Days Of Astronomy

Link : astrosphere.org ; http://unawe.org/kids/unawe1119/

Description: Space scoop, news for children. 

Bio: Richard Drumm is President of the Charlottesville Astronomical Society and President of 3D – Drumm Digital Design, a video production company with clients such as Kodak, Xerox and GlaxoSmithKline Pharmaceuticals. He was an observer with the UVa Parallax Program at McCormick Observatory in 1981 & 1982. He has found that his greatest passion in life is public outreach astronomy and he pursues it at every opportunity.

Today’s sponsor: This episode of “365 Days of Astronomy” is sponsored by — no one. We still need sponsors for many days in 2016, so please consider sponsoring a day or two. Just click on the “Donate” button on the lower left side of this webpage, or contact us at signup@365daysofastronomy.org.

Transcript:
This is the 365 Days of Astronomy Podcast. Today we bring you a new episode in our Space Scoop series. This show is produced in collaboration with Universe Awareness, a program that strives to inspire every child with our wonderful cosmos.

Raiders of the Lost Stars
Like a team of real-life Indiana Joneses, scientists have explored our galaxy and found a treasure trove of hidden gems.

OK, Indy wasn’t looking for gems specifically. It was historical artifacts he was going for, but work with me here, work with me!

These gems are much more spectacular than the diamonds that Indiana Jones might have hoped to find – they are collections of dazzling stars!

Most stars that weigh half as much as the Sun or more, are born in groups called ‘open clusters’. There are typically a couple thousand stars in an open cluster, but many of them are tiny, dim M Dwarves.

All the stars in an open cluster formed from the same GMC or Giant Molecular Cloud and are approximately the same age as a result.

If places like the Orion nebula, M42 are stellar nurseries where stars are born, then open clusters are the kindergartens where the young stars get to hang out together for a time.

But these can be very dusty places, which makes some of these open clusters difficult to find for most telescopes.

They are hidden in the dark, dusty areas of the galaxy.

The dust in front of the clusters makes them appear 10,000 to 100 million times fainter than they’d be if they weren’t hidden in the dark cloud of gas.

However, a multinational team of astronomers used a telescope called the VISTA telescope, at the Paranal Observatory in Chile, to survey the sky in infrared light.

This is light that penetrates dust clouds easily and lets our telescopes look right into them.

The VISTA Variables in the Vía Láctea program, called VVV for short, has been scanning the central bulge of the Milky Way and the nearby parts of the galactic disc in that infrared light.

This program was granted a total of 1,929 hours of observing time over a five year period. That’s a LOT of time! And the 4.1 meter diameter VISTA telescope is a LOT of telescope!

Oh, by the way, Vía Láctea is the Latin name for the Milky Way.

They have discovered 96 new open clusters in the galaxy that had previously been hidden from view.

This is the first time that so many faint and small open clusters have been found all at once!

In addition to using infrared light to look past the dust and into the cluster forming regions, the astronomers had another trick up their sleeves.

You see, low contrast star clusters which are seen in front of the crowded star fields that are common in the galaxy’s plane are a big problem for astronomers.

Figuring out which stars are the cluster and which stars are just in the background or foreground is kinda hard.

So they used computer software to do “field star decontamination” where the stars that aren’t part of the cluster are statistically eliminated, making the clusters more visible.

They also performed so-called “point-spread function fitting” to determine the brightness of hundreds of stars in each image.

With tools like these in the hands of the astronomers, these star clusters could run but they can’t hide!

Though they found a good number of clusters, they didn’t find any in the galactic bulge. Not yet, at least, so they’re continuing to search for clusters there.

Open clusters can contain up to a few thousand stars, but most of the ones that have just been discovered only have about 10 or 20 stars each. 1% of the size of a regular open cluster!

So they’re just little guys! They’re also young. Most of them are younger than 5. . . Million years old.

Hey, Here’s A Cool Fact:
2,500 open clusters have been found in the Milky Way, but we think there might be another 30,000 still waiting to be discovered!

Could you kids out there someday be the Young Indiana Jones who finds these lost gems?

Thank you for listening to the 365 Days of Astronomy Podcast!
End of podcast:

365 Days of Astronomy
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The 365 Days of Astronomy Podcast is produced by Astrosphere New Media. Audio post-production by Richard Drumm. Bandwidth donated by libsyn.com and wizzard media. You may reproduce and distribute this audio for non-commercial purposes. Please consider supporting the podcast with a few dollars (or Euros!). Visit us on the web at 365DaysOfAstronomy.org or email us at info@365DaysOfAstronomy.org.  This year we will celebrate more discoveries and stories from the universe. Join us and share your story. Until tomorrow! Goodbye!

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