Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Hubble Catches Heavyweight Runaway Star Speeding from 30 Doradus

12.05.2010
A heavy runaway star is rushing away from a nearby stellar nursery at more than 250,000 miles an hour, a speed that will get you to the Moon and back in two hours. The runaway is the most extreme case of a very massive star that has been kicked out of its home by a group of even heftier siblings.

The homeless star is on the outskirts of the 30 Doradus nebula, a raucous stellar breeding ground in the nearby Large Magellanic Cloud. The finding bolsters evidence that the most massive stars in the local universe reside in 30 Doradus, making it a unique laboratory for studying heavyweight stars. 30 Doradus, also called the Tarantula Nebula, is roughly 170,000 light-years from Earth.

Tantalizing clues from three observatories, including the Hubble Space Telescope's newly installed Cosmic Origins Spectrograph (COS), and some old-fashioned detective work, suggest that the star may have traveled about 375 light-years from its suspected home, a giant star cluster called R136. Nestled in the core of 30 Doradus, R136 contains several stars topping 100 solar masses each.

The observations offer insights into how massive star clusters behave.

"These results are of great interest because such dynamical processes in very dense, massive clusters have been predicted theoretically for some time, but this is the first direct observation of the process in such a region," says Nolan Walborn of the Space Telescope Science Institute in Baltimore and a member of the COS team that observed the misfit star. "Less massive runaway stars from the much smaller Orion Nebula Cluster were first found over half a century ago, but this is the first potential confirmation of more recent predictions applying to the most massive young clusters."

Runaway stars can be made in a couple of ways. A star may encounter one or two heavier siblings in a massive, dense cluster and get booted out through a stellar game of pinball. Or, a star may get a 'kick' from a supernova explosion in a binary system, with the more massive star exploding first.

"It is generally accepted, however, that R136 is sufficiently young, 1 million to 2 million years old, that the cluster's most massive stars have not yet exploded as supernovae," says COS team member Danny Lennon of the Space Telescope Science Institute. "This implies that the star must have been ejected through dynamical interaction."

The runaway star research team, led by Chris Evans of the Royal Observatory Edinburgh, published the study's results May 5 in the online edition of The Astrophysical Journal Letters.

Astronomers have been on the trail of this rogue star since 2006 when a team led by Ian Howarth of University College London spotted it with the Anglo-Australian Telescope at Siding Spring Observatory. The observation revealed that the stellar misfit was an exceptionally hot, massive blue-white star and relatively far from any cluster in which such stars are usually found.

Hubble astronomers unexpectedly picked up another clue when they used the star as a target to calibrate the COS instrument, installed in May 2009 during Servicing Mission 4. Those ultraviolet spectroscopic observations, made in July 2009, showed that the wayward star is unleashing a fury of charged particles in one of the most powerful stellar winds known, a clear sign that it is extremely massive, perhaps as much as 90 times heavier than the Sun. The star, therefore, also must be very young, about 1 million to 2 million years old, because extremely massive stars live only a few million years.

Sifting through Hubble's archive of images, astronomers found another important piece of evidence. An optical image of the star taken by the Wide Field Planetary Camera 2 in 1995 revealed that it is at one end of an egg-shaped cavity. The cavity's glowing edges stretch behind the star and point in the direction of its home in 30 Doradus.

Another spectroscopic study from the European Southern Observatory's Very Large Telescope (VLT) at the Paranal Observatory in Chile revealed that the star's velocity is constant and not a result of orbital motion in a binary system. Its velocity corresponds to an unusual motion relative to the star's surroundings, evidence that it is a runaway star.

The study also confirmed that the light from the runaway is from a single massive star rather than the combined light of two lower-mass stars. In addition, the observation established that the star is about 10 times hotter than the Sun, a temperature that is consistent with a high-mass object.

The VLT observations are part of a legacy program called the FLAMES (VLT multi-object spectrograph) Tarantula Survey. The survey, conducted by an international team led by Evans of the Royal Observatory, comprises more than 900 stars in the 30 Doradus region. Like the COS observations of the star, the FLAMES results also were serendipitous. The star's location is far from the nebula's central region, placing it at the edge of the FLAMES survey field.

The renegade star may not be the only runaway in the region. Two other extremely hot, massive stars have been spotted beyond the edges of 30 Doradus. Astronomers suspect that these stars, too, may have been ejected from their home. They plan to analyze the stars in detail to determine whether 30 Doradus might be unleashing a barrage of massive stellar runaways into the surrounding neighborhood.

The wayward star will continue to streak across space, says team member Paul Crowther of the University of Sheffield in England, and will eventually end its life in a titanic supernova explosion, likely leaving behind a remnant black hole.

For images and more information, visit:

http://hubblesite.org/news/2010/14
http://www.spacetelescope.org/news/heic1008/
http://www.nasa.gov/hubble
The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA's Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI) conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc. in Washington, D.C.

Donna Weaver | Newswise Science News
Further information:
http://www.stsci.edu

More articles from Physics and Astronomy:

nachricht Further Improvement of Qubit Lifetime for Quantum Computers
09.12.2016 | Forschungszentrum Jülich

nachricht Electron highway inside crystal
09.12.2016 | Julius-Maximilians-Universität Würzburg

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: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>