Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers spy stellar bull´s eye

27.03.2003


Dramatic images reveal unique star explosion



In the early months of 2002, astronomers scanning the sky saw something highly unusual - and they still don’t know exactly what it is. A star suddenly flashed to 600,000 times its previous brightness. For a brief time, it was the brightest star in the galaxy.

As the light from the outburst spread into space, it reflected from surrounding rings of dust to reveal a spectacular, multicolored bull’s eye that is now 3 light years across and still growing.


"This is such an exciting discovery," said NSF-supported astronomer Sumner Starrfield of Arizona State University, one of the researchers reporting the discovery in the March 27 Nature. "It was like a light bulb going off, and you can see the light echoing off surrounding material."

The new stellar outburst is described in the Nature article by an international, multi-agency team of researchers led by Howard Bond of the Space Telescope Science Institute in Baltimore, Maryland. The team presents both a novel approach to calculating our distance from the star and dramatic NASA Hubble Space Telescope images of the "light echo" as it emanates outwards.

While the visual effect is stunning, the object is more than a pretty picture. Light echoes are rare, and this star’s outburst has many unusual characteristics.

"We don’t know what has caused this to happen," said Starrfield. "This object got bigger and brighter and cooler, but we don’t know why. Right now we know the effects and we’re trying to use the effects to determine the cause," he said.

Starrfield and colleague R. Mark Wagner of the University of Arizona used ground-based telescopes to study the light from the star, named V838 Monocerotis (V838 Mon).

The group found that V838 Mon is actually a two-star, binary system, with one smaller and hotter (with a surface temperature of approximately 18,000 degrees Celsius) and the other star much larger and cooler (roughly 2,000 degrees Celsius).

The star characteristics help the researchers determine the objects’ distance from Earth, with critical data coming from both space-based images and ground-based observations. While Starrfield and his colleagues are still compiling ground-based data with NSF support, the researchers currently estimate the distance between Earth and V838 Mon to be at least 20,000 light years.

Many characteristics of the stellar outburst are unique. But, the smaller of the two stars looks similar to a well known type of star known as a B3 main sequence star, "and we know how to calculate our distance to that type of star," says Starrfield. "We know how bright such a star should be and can therefore get the distance if it is in fact similar," he added.

Said Wagner, "We are getting reasonably good agreement between the distance we infer from the light echo and the distance we estimate based on our ground-based observations of the hotter star."

Relative to its distance, the eruption of V838 Mon was incredibly bright. "In fact, the eruption was bright enough to be seen with binoculars," said Starrfield.

An additional part of the puzzle is that the outburst may be recurrent, and researchers believe the concentric envelopes of gas and dust surrounding V838 Mon may be remnants of previous outbursts, not transient debris from other star systems.

Although vast amounts of light and gas were shed by the outburst, the brightening star did not completely disperse its outer layers like exploding stars known as novae. Instead, the star expanded to an enormous size, cooling at its surface so that the outermost edges are unusually cool.

"If the larger of the two stars was at the center of our solar system, it would be big enough to engulf everything out to Jupiter," said Starrfield, "and it’s still growing."

The researchers believe that the light echo will be observable through the next decade, and they plan to use the time to make measurements with an array of space- and ground-based telescopes.

"This research will likely have significant impact on our understanding of the late phases of stellar evolution," said Phil Ianna, the NSF program officer who oversees support for the project. "Once again we see how the collaborative efforts of researchers combining space-based and ground-based data reveal details about objects not even imagined before."

The research team included investigators from the Space Telescope Institute in Baltimore, Maryland; the Universities Space Research Association at the U.S. Naval Observatory in Flagstaff, Arizona; the European Space Agency; Arizona State University; the Large Binocular Telescope Observatory at the University of Arizona at Tucson; the Isaac Newton Group of Telescopes in Spain’s Canary Islands; and the INAF-Osservatorio Astronomico di Padova in Asiago, Italy.

Josh Chamot | National Science Foundation
Further information:
http://www.nsf.gov
http://www.nsf.gov/home/news.html
http://www.nsf.gov/sbe/srs/stats.htm

More articles from Physics and Astronomy:

nachricht SF State astronomer searches for signs of life on Wolf 1061 exoplanet
20.01.2017 | San Francisco State University

nachricht Molecule flash mob
19.01.2017 | Technische Universität Wien

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: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Helmholtz International Fellow Award for Sarah Amalia Teichmann

20.01.2017 | Awards Funding

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>