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 Black hole spin cranks-up radio volume
15.01.2018 | National Institutes of Natural Sciences

nachricht The universe up close
15.01.2018 | Georg-August-Universität Göttingen

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: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

Im Focus: A thermometer for the oceans

Measurement of noble gases in Antarctic ice cores

The oceans are the largest global heat reservoir. As a result of man-made global warming, the temperature in the global climate system increases; around 90% of...

Im Focus: Autoimmune Reaction Successfully Halted in Early Stage Islet Autoimmunity

Scientists at Helmholtz Zentrum München have discovered a mechanism that amplifies the autoimmune reaction in an early stage of pancreatic islet autoimmunity prior to the progression to clinical type 1 diabetes. If the researchers blocked the corresponding molecules, the immune system was significantly less active. The study was conducted under the auspices of the German Center for Diabetes Research (DZD) and was published in the journal ‘Science Translational Medicine’.

Type 1 diabetes is the most common metabolic disease in childhood and adolescence. In this disease, the body's own immune system attacks and destroys the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Fachtagung analytica conference 2018

15.01.2018 | Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

 
Latest News

Black hole spin cranks-up radio volume

15.01.2018 | Physics and Astronomy

A matter of mobility: multidisciplinary paper suggests new strategy for drug discovery

15.01.2018 | Life Sciences

New method to map miniature brain circuits

15.01.2018 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>