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 Gamma-ray flashes from plasma filaments
18.04.2018 | Max-Planck-Institut für Kernphysik

nachricht How does a molecule vibrate when you “touch” it?
17.04.2018 | Universität Regensburg

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: Gamma-ray flashes from plasma filaments

Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.

The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...

Im Focus: Basel researchers succeed in cultivating cartilage from stem cells

Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.

Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...

Im Focus: Like a wedge in a hinge

Researchers lay groundwork to tailor drugs for new targets in cancer therapy

In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...

Im Focus: The Future of Ultrafast Solid-State Physics

In an article that appears in the journal “Review of Modern Physics”, researchers at the Laboratory for Attosecond Physics (LAP) assess the current state of the field of ultrafast physics and consider its implications for future technologies.

Physicists can now control light in both time and space with hitherto unimagined precision. This is particularly true for the ability to generate ultrashort...

Im Focus: Stronger evidence for a weaker Atlantic overturning

The Atlantic overturning – one of Earth’s most important heat transport systems, pumping warm water northwards and cold water southwards – is weaker today than any time before in more than 1000 years. Sea surface temperature data analysis provides new evidence that this major ocean circulation has slowed down by roughly 15 percent since the middle of the 20th century, according to a study published in the highly renowned journal Nature by an international team of scientists. Human-made climate change is a prime suspect for these worrying observations.

“We detected a specific pattern of ocean cooling south of Greenland and unusual warming off the US coast – which is highly characteristic for a slowdown of the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur

09.04.2018 | Event News

 
Latest News

New capabilities at NSLS-II set to advance materials science

18.04.2018 | Materials Sciences

Strong carbon fiber artificial muscles can lift 12,600 times their own weight

18.04.2018 | Materials Sciences

Polymer-graphene nanocarpets to electrify smart fabrics

18.04.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>