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Rare Lone Neutron Star Found Nearby

Posted by kdawson on from the howdy-neighbor dept.

F4_W_weasel sends us to the BBC for news of the eighth lone neutron star ever discovered. It has no associated supernova remnant, binary companion, or radio pulsations. It's in our stellar neighborhood, at most 1,000 light years away. The object emits all its radiation (as far as wa can detect with current instruments) in X rays. The object is called Calvera, after the bad guy in The Magnificent Seven — which is itself the collective nickname for the seven such objects previously known.

14 of 37 comments (clear)

  1. Dragon's Egg by Gospodin · · Score: 2, Interesting

    When I saw the title I was hoping for a Robert L. Forward Dragon's Egg type of thing. But apparently it isn't quite that nearby.

    --
    ...following the principles of Heisenburger's Uncertain Cat...
    1. Re:Dragon's Egg by fishdan · · Score: 2, Informative

      I was hoping that it would have some weird tidal effect.

      --
      Nothing great was ever achieved without enthusiasm
  2. Raw data by ELProphet · · Score: 4, Insightful

    He compared a catalogue of 18,000 X-ray sources from the German-American Rosat satellite, which operated from 1990 to 1999, with catalogues of objects that appeared in visible light, infrared light, and radio waves.

    Makes me wonder how much data has been colected, but not analyzed, and what other astronomical wonders and oddities will be found when that data is analyzed.

    1. Re:Raw data by networkBoy · · Score: 3, Interesting

      Lots, much of it, and many respectively.
      Once MIT gets their glass plate collection on-line, expect even more discoveries.
      -nB

      --
      whois gawk date unzip strip find touch finger mount join nice man top fsck grep eject more yes exit umount sleep dump
    2. Re:Raw data by mbone · · Score: 2, Interesting

      Many petabytes of astronomical data have been collected. It is a good bet that all or almost all of it have been analyzed for some purpose (whatever paid for the
      data collection), but there is no limit to the ways that things can be analyzed (did it change strenght with time ? Is it in other catalogs ? Is it stronger
      in some wavelength than usual ? etc. etc.) So, in that sense the surface has hardly been scratched and this work will literally never be completed.

      There is lots of room for amateurs to make discoveries in these "virtual telescopes," and you can expect some cool discoveries to come from guys running software in their basement.

  3. Rasberry! by Mike73 · · Score: 2, Funny

    There's only one man who would dare give me the rasberry... LONE STAR!

  4. I want a little piece of it... by nadamucho · · Score: 2, Funny

    ...Even just a teaspoon. Maybe NASA can hook it up. Can't weigh all that much, can it?

  5. Hardly news... by Actually,+I+do+RTFA · · Score: 2, Funny

    Most websites I go to extol their collection of rare, lone(ly) stars near me, and even offer to put me in direct contact with them. Take that SETI.

    --
    Your ad here. Ask me how!
  6. How certain are they about the radio noise? by jd · · Score: 2, Informative
    Let's face it, a pulsar shoots incredibly focussed beams of radiation from the poles and the poles alone. It is so incredibly focussed that even though all the object is doing is spinning off-axis by a small amount, we only see clearly-defined pulses. All it requires is that we're never inside that very narrow cone that gets a signal, and we would observe something from which we would never get any pulses.

    There are also other variants of these objects - magnetars, for example - that are, if not well-known, then at least recognized and classified.

    To decide this could be something totally new is an interesting decision but nothing in the press release is telling me why they have made that specific decision over, say, merely seeing a regular pulsar at too great an angle to ever see the pulses.

    --
    It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
    1. Re:How certain are they about the radio noise? by AJWM · · Score: 2, Insightful

      I think the "new discovery" part is the "without supernova remnant". Aren't most pulsars embedded in their supernova remnants?

      May be an age thing. If the object is young enough that the remnant is still nearby and visible, it's young enough that it hasn't yet shed a lot of energy through its pulsar (etc) emissions, and vice versa. An old neutron star whose remnant nebula is long gone is likely to be a slow, feeble pulsar at best.

      --
      -- Alastair
    2. Re:How certain are they about the radio noise? by archen · · Score: 3, Interesting

      "I think the "new discovery" part is the "without supernova remnant". Aren't most pulsars embedded in their supernova remnants?"

      While true I don't think it's exactly all that interesting that you'd find a neutron star without the remnants. There are many things that could have happened to eject such an object out of its normal position. Take a binary star system for example. If one star lost significant mass, and another gained (mass blown off of its partner) than an irregular orbit would cause the first to slingshot. That's one theory anyway.

    3. Re:How certain are they about the radio noise? by rerutledge · · Score: 5, Informative

      Actually, the "new discovery" part is that we used a standard method to discover a specific class of neutron star -- the isolated, X-ray bright, radio dim class -- but found an object that, if we assumed it was a member of that class, would have placed it well outside the galactic plane. That offends theorists, mightily, since they are unlikely to be produced in SNe up there (no stars) and cool to quickly to travel there from the plane, unless this particular object is moving with a velocity much much greater than ever observed from a neutron star before (>5100 km/sec; 300 km/sec is more typical). We compared the NS with other classes we know; and it just doesn't fit well with those, with the exception of a radio pulsar whose beam does not cross our line of sight. If that is true, then Calvera's X-ray flux is such that it should be close by, perhaps the closest known neutron star. Other notes: supernovae remnants dissipate after about 10,000 years (not 10 Billion). Most of the neutron stars we've observed are not observed with their supernova remanent, but are instead radio pulsars wandering alone. I'll try to hang out a bit and field more questions.

  7. could be an off-axis pulsar by renard · · Score: 2, Informative
    As you say, jd, it could be an off-axis pulsar. (Note that we did do a search for radio pulsations, and none were seen.) The "off-axis pulsar" hypothesis is what we are banking on when we say it might be the closest neutron star to Earth (250 to 1000 light years). The current record-holder is 1RXSJ1856.5-3754, at 540 light years.

    None of the known radio pulsars are closer to Earth than that.

    Cheers,
    renard / Derek Fox

  8. Re:Am I just being apathetic? by rerutledge · · Score: 3, Interesting

    Here's one way it *may* matter: The best explanation we have for this object, at this point, is that it is a nearby neutron star. If it is spinning rapidly (and that's an if -- we don't know how rapidly it is spinning) and it is not a perfect sphere, then it can be giving off gravitational radiation -- if, in fact, graviational radiation exists as predicted. The fact that it's nearby would make it easier to detect such radiation -- so the object is a potential target for existing gravitational wave detectors, such as LIGO. But that only matters if theories of gravity are of interest to you.