. 24/7 Space News .
STELLAR CHEMISTRY
Aging a Flock of Stars in the Wild Duck Cluster
by Emily Walla , UA/NASA Space Grant Intern
Tucson AZ (SPX) Nov 08, 2018

An image of the Wild Duck Cluster was captured by the MPG/ESO 2.2-metre telescope at the La Silla Observatory in Chile. The blue stars at the center of the image are the stars of the cluster. Every star in the Wild Duck Cluster is roughly 250 million years old. Older, redder stars surround the cluster. (Image: European Southern Observatory)

Do star clusters harbor many generations of stars or just one? Scientists have long searched for an answer and, thanks to the University of Arizona's MMT telescope, found one in the Wild Duck Cluster, where stars spin at different speeds, disguising their common age.

In a partnership between the UA and the Korean Astronomy and Space Science Institute, a team of Korean and Belgian astronomers used UA instruments to solve a puzzle about flocks of stars called open clusters.

Astronomers have long believed that many open clusters consist of a single generation of stars because once stars have formed, their radiation blows away nearby material needed to make new stars.

But in the Wild Duck Cluster - known by scientists as Messier 11, or M11 - stars of the same brightness appear in different colors, suggesting they are of different ages. Unless scientists had missed important clues about stellar evolution, there had to be another explanation for the spread of colors in this accumulation of about 2,900 stars.

"Astronomers have been working on this question for decades," said Serena Kim, an associate astronomer at the UA's Steward Observatory. "Do clusters form in one generation or multiple generations? Our study answered this question for the Wild Duck Cluster."

Beomdu Lim of Kyung Hee University led an international team of astronomers who used the MMT telescope - jointly operated by the UA and the Smithsonian Astrophysical Observatory - to study the cluster. The team discovered that it is not the stars' ages that cause them to appear in a spread of color: it is their rotation.

Open clusters contain thousands of stars that astronomers hypothesize formed from the same giant clouds of gas. These stars come in all sizes, from short-lived, giant blue stars dozens of times more massive than our sun, to long-lived low-mass dwarves that will burn for 10 billion years or longer. The brightness and color of each star changes as it grows older, allowing scientists to determine its age.

"As a star is getting older and older, it brightens and becomes redder," Lim said.

Astronomers plot young stars' brightness and color in a diagonal line - from bright, blue and massive at the top of the line, down to faint, red and less massive at the bottom - called the main sequence.

The turning point - the point at which a star ages and veers off the main sequence - is used to determine the age of clusters based on the known life expectancy of each star. If the stars leave the main sequence at the same point, like cars on a freeway taking the same exit, then the stars of the cluster are all the same age.

In the Wild Duck Cluster, however, the stars veer off the diagonal at different points, like cars taking different exits along a freeway.

"This does not seem intuitive, since the stars in an open cluster like M11 are thought to belong to the same generation," Kim said.

Lim and his team set out to discover what stellar properties could potentially explain this pattern.

They turned the MMT telescope toward the cluster to examine the color spectrum of the stars using an Hectochelle. The instrument acts like a prism and spreads starlight into its components, which astronomers call a spectrum. The spectra are like barcodes, with each line identifying a different chemical in the star's makeup.

Hectochelle can capture detailed spectra of many stars at once, making it an ideal instrument to observe clusters like the Wild Duck, which consist of thousands of stars.

As a star rotates, one side of it is moving toward the Earth and the other is moving away. The half of the star rotating toward the Earth emits light with wavelengths that look squished, making the light look bluer than it would be if the star were not moving.

The half of the star rotating away from the Earth causes the wavelengths to look stretched, making its light seem redder. This squishing and stretching causes spectral lines to spread across a range of wavelengths, rather than spiking at just one.

The stars in the Wild Duck Cluster, it turns out, are spread out in the color spectrum not because of different ages, but because of different rotational periods.

"The effects of rotation on stellar evolution were often neglected in the past," said Yael Naze, an astronomer at the University of Liege in Belgium and co-author of the paper.

The spectra also revealed that the stars are spinning at different rates. Lim and his team performed computer simulations to find out how fast each star is rotating. "A rapidly rotating star can remain in the main sequence stage longer than a slowly rotating star," Lim said. "A wide range of velocities of stars results in differences of lifetimes among the stars."

Rotational speed is like a fountain of youth to a star: The faster it spins, the better it mixes hydrogen - the star's fuel - into its core. The more hydrogen the core receives, the longer the star lives, causing it to appear redder than younger siblings.

Stars in the cluster appear in different colors because the cloud they were born in set them into motion that would extend the lifetime for some of them.

Though not a part of the Wild Duck Cluster study, Kim has worked with Lim in the past to study other star clusters and uncover mysteries of star formation. Their collaborations are part of a growing partnership between the UA and the Korean Astronomy and Space Science Institute.

In addition to teaming up to use the MMT telescope, the UA and the Korean Astronomy and Space Science Institute are partners in the Giant Magellan Telescope Project; the UA's Richard F. Caris Mirror Lab is manufacturing the world's largest mirrors.

For more information on the UA's involvement, visit here. For more information on Korean Astronomy and Space Science Institute's involvement, visit the K-GMT Science Group online here.


Related Links
University of Arizona's
Stellar Chemistry, The Universe And All Within It


Thanks for being there;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Monthly Supporter
$5+ Billed Monthly


paypal only
SpaceDaily Contributor
$5 Billed Once


credit card or paypal


STELLAR CHEMISTRY
Tiny old star has huge impact
Hilo HI (SPX) Nov 06, 2018
A tiny star found in our galactic neighborhood is presenting astronomers with a compelling glimpse into the history of our galaxy and the early universe. The star has some very interesting characteristics: it's small, it's old, and most significantly it's made of material very similar to that spewed by the Big Bang. To host a star like this suggests that the disk of our galaxy could be up to three billion years older than previously thought. "Our Sun likely descended from thousands of generations ... read more

Comment using your Disqus, Facebook, Google or Twitter login.



Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

STELLAR CHEMISTRY
'Dust up' on International Space Station hints at sources of structure

Experience high-res science in first 8K footage from space

Roscosmos, NASA to adjust ISS program to fit with lunar missions

Russia's Roscosmos confirms computer glitch on board ISS

STELLAR CHEMISTRY
Hole in Soyuz MS-09 hull could have been drilled before launch

Russia to hold 2 new space launches in wake of Soyuz failure

Fregat Upper Stage Separates From Soyuz Carrier Bringing Satellite to Orbit

Small rockets are taking off

STELLAR CHEMISTRY
Evidence of outburst flooding indicates plentiful water on early Mars

The Mars InSight Landing Site Is Just Plain Perfect

Curiosity on the move again

Water cycle along the northern rim of Hellas Basin throughout Mars' history

STELLAR CHEMISTRY
China unveils new 'Heavenly Palace' space station as ISS days numbered

China's space programs open up to world

China's commercial aerospace companies flourishing

China launches Centispace-1-s1 satellite

STELLAR CHEMISTRY
Telstar 18 VANTAGE satellite now operational over Asia Pacific

How Max Polyakov from Zaporozhie develops the Ukrainian space industry

SpaceFund launches the world's first space security token to fund the opening of the high frontier

ESA on the way to Space19+ and beyond

STELLAR CHEMISTRY
Eye-tracking glasses provide a new vision for the future of augmented reality

NUS researchers turn plastic bottle waste into ultralight supermaterial

Video game action heads for the cloud

Making steps toward improved data storage

STELLAR CHEMISTRY
Laser tech could be fashioned into Earth's 'porch light' to attract alien astronomers

Laboratory experiments probe the formation of stars and planets

NASA retires Kepler Space Telescope, passes planet-hunting torch

Rocky and habitable - sizing up a galaxy of planets

STELLAR CHEMISTRY
SwRI team makes breakthroughs studying Pluto orbiter mission

ALMA maps temperature of Jupiter's icy moon Europa

NASA's Juno Mission Detects Jupiter Wave Trains

WorldWide Telescope looks ahead to New Horizons' Ultima Thule glyby









The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.