Rare Lone Neutron Star Found Nearby

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.

Dragon's Egg

[Gospodin]

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

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[fishdan]

I was hoping that it would have some weird tidal effect [wikipedia.org].

Perhaps with a hyperdrive motor?

[PIPBoy3000]

As long as you remember that there is a tide [iblist.com].

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[sepelester]

I was hoping for a Hades neutron star as in Andrew Reynolds' Revelation Space [wikipedia.org]. THAT could be useful (if it were closer)

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[sepelester]

Oh, that's Alastair Reynolds. Bummer. (sometimes I need two mandatory previews and a triple captcha to get it right)

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[Dr. Manhattan]

Personally, I thought of BVS-1 [wikipedia.org] (Phthsspok's Star) [wikipedia.org]. Too far away, though.

Raw data

[ELProphet]

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.

Re:Raw data

[networkBoy]

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

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[mbone]

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 disc

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[rerutledge]

I can answer that. Quite a lot of data has been collected, but not fully exploited.

Rasberry!

[Mike73]

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

I want a little piece of it...

[nadamucho]

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

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[ScentCone]

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

See, the problem is you're asking for it volumetrically. You need to ask for it terms of mass, as usually expressed in LOC (Libraries of Congress). This is NOT to be confused with the the ECLOC (Entire Contents of the Library of Congress), which is a data throughput metric. No, we're talking about the mass of the actual masonry, furnishings, and plumbing. The mass of the staff is only taken into account under special ci

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[iggymanz]

well, there is always the LOC-CDTNSD unit of volume, the Library of Congress Crushed Down to Neutron Star Density. I like units that are useful when the astronomical and everyday scale intersect. Like measuring hard intrastellar vacuum in NPGWBCC, Neurons per GW Bush's Cranial Capacity

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[teslar]

Well, for those who are interested, the Spiegel [spiegel.de] mentions that a cubic centimeter of that stuff would weigh about a billion metric tons on earth - what's your teaspoon made of? ;)

Hardly news...

[Actually, I do RTFA]

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.

How certain are they about the radio noise?

[jd]

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.

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[AJWM]

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.

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[m2943]

Age alone can't be it; supernova remnants as old as 10 billion years have been observed. But it may have become ejected from wherever it originated.

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[archen]

"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

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[jd]

Possibly. The article was... unclear. Even there, though, one should avoid creating new categories unless there is a scientific or budgetary reason for doing so. Is it possible, for example, that interstellar winds were simply very strong at the time the star went supernova and thus the debris simply got blasted clear of it? To show that, you'd want to estimate the age, determine how far the debris could have traveled and then look to see if there are small pockets of unusually dense dust/gas in deep space.

Re:How certain are they about the radio noise?

[rerutledge]

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.

could be an off-axis pulsar

[renard]

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

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[Scott Ransom]

Hey Derek: What telescope did you use?

BTW: why "renard'?

Am I just being apathetic?

[DaveWick79]

Why does this matter? I wouldn't miss 8 stars that I could see, what's the point in analyzing thousands of pages of data to determine that there is one more star out there that I can't see.

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[Chris Burke]

Why does this matter? I wouldn't miss 8 stars that I could see, what's the point in analyzing thousands of pages of data to determine that there is one more star out there that I can't see.

For you? No point at all. Convenient that you aren't being asked to do any of the analysis then, isn't it?

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[Anonymous Coward]

> Why does this matter?

Because it's HEADING STRAIGHT FOR US!!!

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[renard]

The importance of this discovery rests on its being a "neutron star", which is a particular kind of dense stellar remnant and not really much of a star at all. Neutron stars are made of pure nuclear matter, about a trillion times denser than the usual stuff, and so they serve as interesting probes of strong gravity and nuclear physics. This particular object is only the 8th member of its class of neutron stars, and possibly the closest to Earth of any neutron star. This relatively close (possible) distanc

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[rerutledge]

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 dete

I Learned Something New From TFA

[LifesABeach]

A Neutron is a Proton mixed with an Electron.

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[Breakfast Pants]

I thought a proton was a neutron mixed with a positron. In an electron/proton combination, the 'positron' part of the proton annihilates the electron, giving off massive energy, so it isn't truly 'both' of them anymore.

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[LifesABeach]

Given that "mixing" of particles can occur, could a Monopole be extracted from a Dipole?