

Anomalous Pulsar In Binary System Stymies Theorists 53
Science Daily has word of a millisecond pulsar in the wrong kind of binary system that has astronomers scratching their heads. According to current models of pulsar evolution, such a system should have no way to develop. The pulsar J1903+0327, which rotates 465 times per second, seems to be in a highly elongated orbit around a Sun-like star. Quoting: "Astronomers think most millisecond pulsars are sped up by material falling onto them from a companion star. This requires the pulsar to be in a tight orbit around its companion that becomes more and more circular with time. The orbits of some millisecond pulsars are the most perfect circles in the Universe, so the elongated orbit of the new pulsar is a mystery."
Re:More than meets the eye? (Score:5, Informative)
Re:A simple answer (Score:4, Informative)
Re:A simple answer (Score:3, Informative)
With planets, you can dissipate energy this with atmospheric drag, firing rockets (if you're a spacecraft), or three-body capture*. Only the last of these works with stars, and that's a dubious proposition since the millisecond pulsar would probably have been pretty close to its partner before the capture making it hard to strip during the encounter.
* In the interest of honesty, tides and gravity waves might do it, too, but in practice, their timescale for action is much too long to assist a capture.
Re:A simple answer (Score:3, Informative)
For this system, assuming it started out in the dense stellar environment in a globular cluster, exchange encounters between multiple stars (3 or 4, i.e. single-binary or binary-binary) can provide the dissipation since the lowest mass stars (i.e. not the pulsar) tend to get energy boosts and are then ejected from the encounter. Alternatively, as you suggest, tides during a very close encounter can lead to a capture.
However, for this system, we have reasons for thinking that a triple system origin is a better explanation than an exchange encounter and subsequent ejection from a globular cluster (all this is described in the paper which will be available on the arXiv tomorrow night and which is on the Science website now).
Scott
Re:A simple answer (Score:3, Informative)
Scott
PS: Note that there is a another slightly different triple scenario that we mention in the paper where, continuing from above, the pulsar ablates away its white dwarf companion with a relativistic wind over a billion years or so and we are left with the pulsar main-sequence binary that we apparently see now.
Re:A simple answer (Score:1, Informative)
Re:A simple answer (Score:1, Informative)
It's also wrong. The creationist propaganda that comes with it is exactly why I get pissed off at creationists and ID people. They try to use flawed scientific arguments that sounds right to the uneducated.
It ignores gravitational interactions with other bodies in the solar system, ignores friction with the atmosphere (although it does include some type of friction when the two bodies are actually touching one another) when you start at ground level, and it doesn't allow you to move the "outer space" starting point.