Fastest Rotating Star Found in Neighboring Galaxy

Article ID: 583599

Released: 5-Dec-2011 9:00 AM EST

Source Newsroom: Space Telescope Science Institute (STScI)

  • Credit: NASA, ESA, and G. Bacon (STScI)

    ARTIST'S VIEW OF FASTEST SPINNING STAR VFTS 102. This is an artist's concept of the fastest rotating star found to date. The massive, bright young star, called VFTS 102 rotates at a million miles per hour, or 100 times faster than our Sun does. Centrifugal forces from this dizzying spin rate have flattened the star into an oblate shape, and spun off a disk of hot plasma, seen edge on in this view from a hypothetical planet. The star may have "spun up" by accreting material from a binary companion star. The rapidly evolving companion later exploded as a supernova. The whirling star lies 160,000 light-years away in the Large Magellanic Cloud, a satellite galaxy of our Milky Way.

  • Credit: NASA, ESA, and A. Feild (STScI)

    FORMATION OF A FAST-ROTATING STAR. This diagram shows one theory for the creation of the fastest spinning star found to date. The more massive star was once a member of a binary pair. Its rapidly aging companion star evolved and expanded, spilling material onto the less evolved star. The star robbed angular momentum from the donor star and spun up to a rotation speed of 1 million miles per hour. The donor star explodes as a supernova and propelled the surviving star away.

  • Credit: ESO, M.-R. Cioni (VISTA Magellanic Cloud survey), and the Cambridge Astronomical Survey Unit

    GROUND-BASED IMAGE OF TARANTULA NEBULA REGION. This view shows part of the stellar nursery called the Tarantula Nebula in the Large Magellanic Cloud, a small neighbor of the Milky Way. At the center lies the brilliant star VFTS 102. This view includes both visible-light and infrared images from the Wide Field Imager at the MPG/ESO 2.2-meter telescope at La Silla, Chile, and the 4.1-meter infrared VISTA telescope at Paranal, Chile. VFTS 102 is the fastest rotating star ever found.

Newswise — Astronomers have found the fastest spinning star ever discovered. The hot blue giant rotates at a dizzying 1 million miles per hour, or 100 times faster than our Sun does. The star is very close to the point at which it would be torn apart due to centrifugal forces if it spun any faster.

Two researchers at the Space Telescope Science Institute in Baltimore, Md., Selma de Mink and Daniel Lennon, are part of an international team of astronomers who used the European Southern Observatory's Very Large Telescope at the Paranal Observatory in Chile to find the massive, bright young star, called VFTS 102. It lies in a neighboring dwarf galaxy, the Large Magellanic Cloud, about 160,000 light-years from Earth. Astronomers think that it may have had a violent past and has been ejected from a double star system by its exploding companion.

The astronomers also found that the star, which is around 25 times the mass of the Sun and about one hundred thousand times brighter, was moving through space at a significantly different speed from its neighbors.

"The remarkable rotation speed and the unusual motion compared to the surrounding stars led us to wonder if this star had an unusual early life. It was suspicious," explained Philip Dufton of Queen's University Belfast, Northern Ireland, United Kingdom, lead author of the paper presenting the results.

This difference in speed could imply that VFTS 102 is a runaway star -- a star that has been ejected from a double star system after its companion exploded as a supernova.

The team suggests that the star could have started life as one component of a binary star system. If the two stars were close, gas from the companion could have streamed over and in the process the star would have spun faster and faster. This would explain one unusual fact -- why it is rotating so fast. After a short life of about ten million years, the massive companion would have exploded as a supernova. The explosion would have led to the ejection of the star and could explain the second anomaly -- the difference between its speed and that of other stars in the region. As it collapsed, the massive companion would then have turned into a pulsar. It is intriguing that there is a nearby supernova remnant and a pulsar. What is not yet clear is whether or not they are related to VFTS 102.

Although the astronomers cannot yet be sure that this is exactly what happened, Dufton concluded, "This is a compelling story because it explains each of the unusual features that we've seen. This star is certainly showing us unexpected sides of the short but dramatic lives of the heaviest stars."

To test this theory, Lennon and de Mink will use NASA's Hubble Space Telescope to make precise measurements of the star's proper motion across space.

This research was presented in a paper in the Astrophysical Journal Letters.

The team is composed of P.L. Dufton (Astrophysics Research Centre, Queen's University Belfast (ARC/QUB), UK), P.R. Dunstall (ARC/QUB, UK), C.J. Evans (UK Astronomy Technology Centre, Royal Observatory Edinburgh (ROE), UK), I. Brott (University of Vienna, Department of Astronomy, Austria), M. Cantiello (Argelander Institut fur Astronomie der Universitat Bonn, Germany, Kavli Institute for Theoretical Physics, University of California, USA), A. de Koter (Astronomical Institute "Anton Pannekoek," University of Amsterdam, The Netherlands), S.E. de Mink (Space Telescope Science Institute, USA), M. Fraser (ARC/QUB, UK), V. Henault-Brunet (Scottish Universities Physics Alliance (SUPA), Institute for Astronomy, University of Edinburgh, ROE, UK), I.D. Howarth (Department of Physics and Astronomy, University College London, UK), N. Langer (Argelander Institut fur Astronomie der Universitat Bonn, Germany), D.J. Lennon (European Space Agency, Space Telescope Science Institute, USA), N. Markova (Institute of Astronomy with NAO, Bulgaria), H. Sana (Astronomical Institute "Anton Pannekoek," University of Amsterdam, The Netherlands), and W.D. Taylor (SUPA, Institute for Astronomy, University of Edinburgh, ROE, UK).

For images and more information about VFTS 102, visit:

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.


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