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 Heating quantum matter: A novel view on topology
22.08.2017 | Université libre de Bruxelles

nachricht Engineering team images tiny quasicrystals as they form
18.08.2017 | Cornell University

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: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

Molecular volume control

22.08.2017 | Life Sciences

When fish swim in the holodeck

22.08.2017 | Life Sciences

Biochemical 'fingerprints' reveal diabetes progression

22.08.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>