Fast spinning, wildly orbiting pulsar puzzles astronomers

William Atkins
Friday, 16 May 2008 19:59

Science - Space

Right now, astronomers theorize that the pulsar and star may have been ejected from a globular star cluster because of the interaction from a third stellar body.

Another theory is that the globular star cluster was itself disturbed when it passed through our Milky Way galaxy, thus throwing off the pulsar and star (along with possibly a third body).

The astronomers think this third star—perhaps a white dwarf—might be orbiting with the other two. They state that about one hundred pulsars have been found, in the past, in two-star, or binary, systems. However, this pulsar could possibly be the first one discovered in a triple-star system.

The astronomers are specifically questioning J1903+0327 because other pulsars have been found orbiting other stars (in binary systems), but only about white dwarfs, which are very old and relatively small stars that have exploded off much of their mass only to be left with their core material.

In addition, these other pulsars were found orbiting white dwarfs in nearly circular orbits, not wild elongated orbits, like with J1903+0327.

Australian astronomer David J. Champion (from the Australia Telescope National Facility), one of the authors of the study, stated "What we have found is a millisecond pulsar that is in the wrong kind of orbit around what appears to be the wrong kind of star. Now we have to figure out how this strange system was produced." [Reuters]

The discovery of J1903+0327 appears in the article “The Discovery of an Eccentric Millisecond Pulsar in the Galactic Plane”.

Its authors are Scott M. Ransom, David J. Champion, Patrick Lazarus, Fernando Camilo, Victoria M. Kaspi, David J. Nice, Paulo C.C. Freire, James M. Cordes, Jason W.T. Hessels, Cees Bassa, Duncan R. Lorimer, Ingrid H. Stairs, Joeri van Leeuwen, Zaven Arzoumnian, Don C. Backer, N.D. Ramesh Bhat, Shami Chatterjee, Crawford Fronefield Shami, Julia S. Deneva, Claude-Andre Faucher-Giguere, B.M. Gaensler, Jinlin Han, Fredrick A. Jenet, Laura Kasian, Vlad I. Kondratiev, Michael Kramer, Joseph Lazio, Maura A. McLaughlin, Ben W. Stappers, Arun Venkataraman, and Wouter Vlemmings.

[Author's Note: Thank you for the correction on "milli-second".]