Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New Study Reveals Stars in Milky Way Have Moved

03.08.2015

New Mexico State University researchers are part of a team of scientists with the Sloan Digital Sky Survey (SDSS) who created a new map of the Milky Way that shows nearly a third of the stars have dramatically changed their obits.

This discovery, published July 29 in “The Astrophysical Journal,” brings a new understanding of how stars are formed, and how they travel throughout our galaxy.


Illustration by Dana Berry/SkyWorks Digital, Inc.; SDSS collaboration

A single frame from an animation shows how stellar orbits in the Milky Way can change. It shows two pairs of stars (marked as red and blue) in which each pair started in the same orbit, and then one star in the pair changed orbits. The star marked as red has completed its move into a new orbit, while the star marked in blue is still moving.

In our modern world, many people move far away from their birthplaces, sometimes halfway around the world,” said Michael Hayden, NMSU astronomy graduate student and lead author of the new study. “Now we're finding the same is true of stars in our galaxy -- about 30 percent of the stars in our galaxy have traveled a long way from where they were born.”

To build a new map of the Milky Way, scientists used the SDSS Apache Point Observatory Galactic Evolution Explorer (APOGEE) spectrograph to observe 100,000 stars during a 4-year period.

For the last six years, NMSU astronomers in the College of Arts and Sciences, along with collaborators from member institutions around the world, have been using the 2.5-meter SDSS telescope at the Apache Point, located in the Sacramento Mountains about 20 miles south of Cloudcroft complete a suite of experiments that includes studies of Milky Way stars to unlock the history of our galaxy.

The key to creating and interpreting this map of the galaxy is measuring the elements in the atmosphere of each star. “From the chemical composition of a star, we can learn its ancestry and life history,” said Hayden, who is completing his Ph.D. at NMSU this summer.

The chemical information comes from spectra, which are detailed measurements of how much light the star gives off at different wavelengths. Spectra show prominent lines that correspond to elements and compounds. Astronomers can tell what a star is made of by reading these spectral lines.


“Stellar spectra show us that the chemical makeup of our galaxy is constantly changing,” said Jon Holtzman, NMSU astronomy professor who was involved in the study. “Stars create heavier elements in their cores, and when the stars die, those heavier elements go back into the gas from which the next stars form.”

As a result of this process of “chemical enrichment,” each generation of stars has a higher percentage of heavier elements than the previous generation did. In some regions of the galaxy, star formation has proceeded more vigorously than in other regions -- and in these more vigorous regions, more generations of new stars have formed. This means the average amount of heavier elements in stars varies among different parts of the galaxy. Astronomers then can determine what part of the galaxy a star was born in by tracing the amount of heavy elements in that star.

Hayden and his colleagues used APOGEE data to map the relative amounts of 15 separate elements, including carbon, silicon, and iron for stars all over the galaxy. What they found surprised them -- up to 30 percent of stars had compositions indicating that they were formed in parts of the galaxy far from their current positions.

When the team looked at the pattern of element abundances in detail, they found that much of the data could be explained by a model in which stars migrate radially, moving closer or farther from the galactic center with time. These random in-and-out motions are referred to as "migration," and are likely caused by irregularities in the galactic disk, such as the Milky Way's famous spiral arms. Evidence of stellar migration had previously been seen in stars near the Sun, but the new study is the first clear evidence that migration occurs throughout the galaxy.

Future studies by astronomers using data from SDSS promise even more new discoveries.

“These latest results take advantage of only a small fraction of the available APOGEE data,” said Steven Majewski, the Principal Investigator of APOGEE. “Once we unlock the full information content of APOGEE, we will understand the chemistry and shape of our galaxy much more clearly.”

NMSU has already begun Phase IV of SDSS, the next six-year mission, which runs through 2020. It will include data from the Sloan telescope at Apache Point Observatory and an additional telescope in Chile, adding to the database with a better view of the southern sky.

Contact Information
Minerva Baumann
Media Relations Director
mbauma46@nmsu.edu
Phone: 575-646-7566

Minerva Baumann | newswise
Further information:
http://www.nmsu.edu

More articles from Physics and Astronomy:

nachricht UNH scientists help provide first-ever views of elusive energy explosion
16.11.2018 | University of New Hampshire

nachricht NASA keeps watch over space explosions
16.11.2018 | NASA/Goddard Space Flight Center

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: UNH scientists help provide first-ever views of elusive energy explosion

Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.

Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...

Im Focus: A Chip with Blood Vessels

Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.

Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

Im Focus: Penn engineers develop ultrathin, ultralight 'nanocardboard'

When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure

Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

European Space Talks: Weltraumschrott – eine Gefahr für die Gesellschaft?

23.10.2018 | Event News

 
Latest News

Purdue cancer identity technology makes it easier to find a tumor's 'address'

16.11.2018 | Health and Medicine

Good preparation is half the digestion

16.11.2018 | Life Sciences

Microscope measures muscle weakness

16.11.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>