Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Massive stars mark out Milky Way's 'missing' arms

17.12.2013
A 12-year study of massive stars has reaffirmed that our Galaxy has four spiral arms, following years of debate sparked by images taken by NASA's Spitzer Space Telescope that only showed two arms.

The new research, which is published online today [17 December] in the Monthly Notices of the Royal Astronomical Society, is part of the RMS Survey, which was launched by academics at the University of Leeds.


This shows the distribution of massive stars in the new study. Our location within the Galaxy is circled in black.

Credit: J. Urquhart et al. Background image by Robert Hurt of the Spitzer Science Center.

Astronomers cannot see what our Galaxy, which is called the Milky Way, looks like because we are on the inside looking out. But they can deduce its shape by careful observation of its stars and their distances from us.

"The Milky Way is our galactic home and studying its structure gives us a unique opportunity to understand how a very typical spiral galaxy works in terms of where stars are born and why," said Professor Melvin Hoare, a member of the RMS Survey Team in the School of Physics & Astronomy at the University of Leeds and a co-author of the research paper.

In the 1950s astronomers used radio telescopes to map our Galaxy. Their observations focussed on clouds of gas in the Milky Way in which new stars are born, revealing four major arms. NASA's Spitzer Space Telescope, on the other hand, scoured the Galaxy for infrared light emitted by stars. It was announced in 2008 that Spitzer had found about 110 million stars, but only evidence of two spiral arms.

The astronomers behind the new study used several radio telescopes in Australia, USA and China to individually observe about 1650 massive stars that had been identified by the RMS Survey. From their observations, the distances and luminosities of the massive stars were calculated, revealing a distribution across four spiral arms.

"It isn't a case of our results being right and those from Spitzer's data being wrong – both surveys were looking for different things," said Professor Hoare. "Spitzer only sees much cooler, lower mass stars – stars like our Sun – which are much more numerous than the massive stars that we were targeting."

Massive stars are much less common than their lower mass counterparts because they only live for a short time – about 10 million years. The shorter lifetimes of massive stars means that they are only found in the arms in which they formed, which could explain the discrepancy in the number of galactic arms that different research teams have claimed.

"Lower mass stars live much longer than massive stars and rotate around our Galaxy many times, spreading out in the disc. The gravitational pull in the two stellar arms that Spitzer revealed is enough to pile up the majority of stars in those arms, but not in the other two," explains Professor Hoare. "However, the gas is compressed enough in all four arms to lead to massive star formation."

Dr James Urquhart from the Max Planck Institute for Radio Astronomy in Bonn, Germany, and lead author of the paper, said: "It's exciting that we are able to use the distribution of young massive stars to probe the structure of the Milky Way and match the most intense region of star formation with a model with four spiral arms."

Professor Hoare concludes, "Star formation researchers, like me, grew up with the idea that our Galaxy has four spiral arms. It's great that we have been able to reaffirm that picture."

Further information

Link to research paper: http://dx.doi.org/10.1093/mnras/stt2006

Professor Melvin Hoare is available for interview. Please contact Sarah Reed, Press Officer, University of Leeds on 0113 34 34196 or email s.j.reed@leeds.ac.uk

Image

Image credit: J. Urquhart et al. Background image by Robert Hurt of the Spitzer Science Center.

University of Leeds

The University of Leeds is one of the largest higher education institutions in the UK and a member of the Russell Group of research-intensive universities.

The 2008 Research Assessment Exercise showed the University of Leeds to be the UK's eighth biggest research powerhouse and the University's vision is to secure a place among the world's leading universities by 2015.

Sarah Reed | EurekAlert!
Further information:
http://www.leeds.ac.uk

More articles from Physics and Astronomy:

nachricht Comet or asteroid? Hubble discovers that a unique object is a binary
21.09.2017 | NASA/Goddard Space Flight Center

nachricht First users at European XFEL
21.09.2017 | European XFEL GmbH

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: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

Im Focus: Fast, convenient & standardized: New lab innovation for automated tissue engineering & drug

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Comet or asteroid? Hubble discovers that a unique object is a binary

21.09.2017 | Physics and Astronomy

Cnidarians remotely control bacteria

21.09.2017 | Life Sciences

Monitoring the heart's mitochondria to predict cardiac arrest?

21.09.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>