Nemesis

[andy lloyd]

The potential for a tiny dwarf star in orbit around our Sun has been knocked about by some serious scientists for many years. It was once thought that a dwarf star (given the name Nemesis) might be lurking at the edge of the Sun's gravitational influence. Every 26 million years, scientists speculated, Nemesis would crash through comet clouds, sending swarms of objects into the planetary zone. This led to an extinction cycle, (as considered by Raup and Sepkowski).

I've been researching this, and similar ideas, for some years. I have completed a book on the subject, recently published, which proposes many new ideas, and backs them up with hard science. Indeed, the latest findings about the many objects being discovered in the outer solar system have only served to create further mystery around this subject.

I would invite interested readers to consider reading my book. I would be more than happy to answer questions and debate the issues on this forum:

http://www.darkstar1.co.uk/dst.html

[andy lloyd]

Hi again. I've been having some difficulties with various astronomy forums trying to get a debate going on this subject. I'm pleased that this threads hasn't been removed at this time and hope this indicates the potential for a future debate should anyone want to discuss this subject. I shall return now and again to see if anyone posts here.

[andy lloyd]

Hi again. I've been having some difficulties with various astronomy forums trying to get a debate going on this subject. I'm pleased that this thread hasn't been removed at this time, and hope this indicates the potential for a future debate on this forum should anyone want to discuss this subject. I shall return now and again to see if anyone posts here. I can promise some lively and interesting discussions.

[CANGAS]

Tell me the truth. If you were innocent and wide eyed and somebody told you some new and really strange stuff, what basis would there be for a debate?

There would only be the basis for "Huh?"

[Billy T]

The potential for a tiny dwarf star in orbit around our Sun has been knocked about by some serious scientists for many years. ...How many orbits have taken place since the Sun/Nemise star pair formed? Assume a plausible but very exocentric initial orbit and let it become more circular as Nemise passes thru sun's local orbit objects. What is the current eccentricity? Why is anything that can be properly called a "star" not detectable with large telescopes and sensitive CCDs? Do some numbers if you have not, and report them to us. More facts please.

[c'est moi]

I hope you are not related to Zeta Talk.

http://www.zetatalk.com

[eburacum45]

Surely such a star (which would have to be a small brown dwarf, or we would have seen it by now) would be outside the Sun's Hill Sphere, so would be too loosely bound to the Sun to be truly in orbit.
Nemesis would have been lost long ago to perturbations by the rest of the galaxy

[UnderWhelmed]

I believe the gravity of such a star would mess the orbits of the planets up... :m:

[blobrana]

By means of high-precision timing thanks to pulsars astronomers now know what the solar barycentre is doing with respect to the rest of the cosmos.
And it is not being pulled around by Planet X.

So there is nothing out there within worrying distance.

The astronomers, Nadia Zakamska, Scott Tremaine, made use of the Australia Telescope National Facility pulsar database (http://www.atnf.csiro.au/research/pulsar/psrcat/)


<b>Constraints on the acceleration of the solar system from high-precision timing</b>
<b>Authors:</b> Nadia L. Zakamska, Scott Tremaine (Princeton University)

Many astronomers have speculated that the solar system contains undiscovered massive planets or a distant stellar companion.
The acceleration of the solar system barycentre can constrain the mass and position of the putative companion. In this paper we use the most recent timing data on accurate astronomical clocks (millisecond pulsars, pulsars in binary systems and pulsating white dwarfs) to constrain this acceleration.
No evidence for non-zero acceleration has been found; the typical sensitivity achieved by our method is a/c=a few times 10^-19 s^-1, comparable to the acceleration due to a Jupiter-mass planet at 200 AU.
The acceleration method is limited by the uncertainties in the distances and by the timing precision for pulsars in binary systems, and by the intrinsic distribution of the period derivatives for millisecond pulsars.
Timing data provide stronger constraints than residuals in the motions of comets or planets if the distance to the companion exceeds a few hundred AU.
The acceleration method is also more sensitive to the presence of a distant companion (closer than 300-400 AU) than existing optical and infrared surveys. We outline the differences between the effects of the peculiar acceleration of the solar system and the background of gravitational waves on high-precision timing.

http://au.arxiv.org/PS_cache/astro-ph/pdf/0506/0506548.pdf

[andy lloyd]

Thanks for your comments. I think I should lay out what I think is out there.

I think there is a significant perturber beyond the Edgeworth-Kuiper Belt, and that it has swept out the area between the Kuiper Gap (cliff) and the inner Oort Cloud. As such its (presumably) elliptical orbit works within parameters that would affect objects between about 50AU and up to about 2000 AU. It is also, presumably, rather nearer its further point than its nearest at this time. (So that's beyond the constraints of the study you have cited above, although that's really quite interesting work!!!).

This Perturber would be the influence that might help to explain the extremely odd behaviours exhibited by certain extended scattered disk objects like Sedna, 2000CR 105 and, now, 'Buffy'. The bizarre orbits of these objects are crying out for the inclusion of an external influence.

I accept that this is a contentious proposal, and one that has many critics. Yet, the outer solar system appears to have a growing number of objects that defy the current model.

Now, it's quite possible that this object was once a factor, but is no more. It may have been perturbed itself, or it may work through an 'oscultation' from a more distant orbit (Matese et al). But some astronomers studying the developing 'shape' of the area beyond Neptune's influence are seeing a pattern emerge, and that seems to be similar to patterns in observed proto-planetary disks around distant young stars. The work of Allen and Quillen is particularly of interest to me, although neither would advocate my views I hasten to add. Nevertheless, a Jovian sized planet may well fit the bill, where a passing star of previous loosely-bound binary would be more problematical.

I guess I would be interseted to hear alternative ideas to explain objects like 'Buffy'...This one seems to have the dynamicists rather stumped.

[blobrana]

Hum,

yeah, it is quite plausible that the Sun formed as a binary system, or that there could have been a `Perturbed` that existed early on in the Suns formation.
But it seems to me that they have long since been perturbed or dissipated.

As for buffy,
Yeah, its orbit is unusual
But it does not rule out the standard outer solar system formation possibility (that Neptune moved inwards etc). Chance encounters by 2004 XR190 with other similar objects could produce a similar orbit.

The real puzzle is Sedna orbit.

It seems that it was created very early on, yet in the entire 4 billion years sedna has managed to survived hundreds of close encounters with other star systems (and nemesis or other bodies) unchanged.
(i assume that a star passes a few light years away every 8 million years and a less than a light year every 80 million years)

BTW, A light year is about 63200 AU

[Nasor]

It seems awfully unlikely to me that such an object could have gone unnoticed all this time. Brown dwarfs are bright in the infrared region. How did we manage to miss such a close brown dwarf when we've been cataloging brown dwarfs many light-years away?

[andy lloyd]

Blobrana: Yes, I would agree with you that a lot can happen over the lifetime of the solar system. Hills did ome computer modelling on passing stars back in 1981 and figured that about 4 such events should have happened during the lifetime of the solar system (and memory tells me that the passage would be within 100AU?). Such close passages may have carved out the Kuiper Cliff, and perturbed the orbits of some of the objects in the EKB, but it may also have created much more difficult problems in terms of de-stabilising the outer solar system.

Studies by Quillen have indicated that a smaller object, in the brown dwarf region down to Jupiter-size, would provide a more gentle effect which keps both sides of the debate happy. Enough perturbation to carve through the outer EKB, without damaging the more stable parts of the solar system observed.

Now, I'd argue that such an influence would have been part of a binary system, or perhaps something more complex still within the Sun's original stellar nursery. I'm given to understand that orbits gretaer than about 3000 years are subject to deterioration over time. Nevertheless, there appear to be loosely bound companion binaries being discovered that remain stable despite these theoretical odds. Indeed, the extra-solar systems teach us a lot about what we DON'T know...which is, of course, a lot of fun. So I figure if we found it out there, someone would re-configure the maths to figure out how it managed it all that time. It doesn't seem too much of a stretch when you look at the sort of stuff Marcy comes up with every so often.

And I agree with you about Sedna. That object just causes so many headaches on so many levels.

Nasor: Well, this particular object is as old as the Sun and so is really pretty dead. The brown dwarfs being discovered light years away tend to be the young variety which still have plenty of life left in them. That is, they are luminous, which this object isn't. Also, I figure it's one of the very tiniest of 'stars', perhaps only a few Jupiters. So maybe its atmospheric temperature is about freezing point of water. It's not that warm anymore.

many folk argue that IRAS would have spotted this object. However, IRAS was not quite as efficient as most people think. A lot of anomalies were never really properly followed up, due to funding and time constraints. One particular anomaly (which I describe in my book) became a point of contention between the British and American astronomers working on the data. The Brits were intrigued; the Yanks shelved it, indefinitely. It created a minor spat at the time. Perhaps that was our object. No one ever found out.

Anotehr possibility is that it's already been 'discovered' and mis-catalogued as a background star. Anyhow, the new range of scope will find it if it's there to be found; WISE is looking for brown dwarfs nearby, and SIRTF is a much better version of IRAS. So I've placed my bets, and I guess it's just a matter of waiting. In the meantime, more of these anomalous objects will continue to be discovered, I'm quite sure...

[Billy T]

...As for buffy, Yeah, its orbit is unusual But it does not rule out the standard outer solar system formation possibility (that Neptune moved inwards etc). Chance encounters by 2004 XR190 with other similar objects could produce a similar orbit....I know nothing about 2004 XR190, perhaps you will post more?

I think there are two possible explanations for Buffy's nearly circular orbit at 47 degrees to the ecliptic.

(1) Solar system stole it from some passing object (more than three bodies so not prohibited.) but the near circular nature of orbit forces a different conclusion:

(2) ETs made it! Back when it was too dangerous to colonize Earth as large meteor impacts were more common. Fact that it gets little solar energy at 57 AUs from sun, they considered to be an asset - their fusion reactors waste heat radiators worked better, but normally they point away from the sun so we have not yet detected the strong IR signature from that radiator (or they all died long ago and were nice enough to shut reactor down first - unlike those jerks who lived on the planet we now call the asteroid belt.).
;)

[andy lloyd]

Star Systems Hint at Possibility of Sun's Nemesis By SPACE.com Staff posted: 19 January 2006

"Kalas and Graham speculate that stars also having sharp outer edges to their debris disks have a companion—a star or brown dwarf—that keeps the disk from spreading outward, similar to how Saturn's moons shape the edges of some of the planet's rings."The story of how you make a ring around a planet could be the same as the story of making rings around a star," Kalas said. Perhaps a passing star ripped off the edges of the original planetary disk, but a star-sized companion, remaining in place, would be necessary to keep the remaining disk material from spreading outward, he figures. The scenario has Kalas and his colleagues thinking that the Sun might also have a companion that keeps the Kuiper Belt confined within a sharp boundary. U.C. Berkeley physics professor Richard Muller has proposed such a star, which he calls Nemesis, but no evidence has been found for one".

http://www.space.com/scienceastronomy/060119_kuiper_stars.html

[Billy T]

Star Systems Hint at Possibility of Sun's Nemesis By SPACE.com Staff posted: 19 January 2006

"Kalas and Graham speculate that stars also having sharp outer edges to their debris disks have a companion—a star or brown dwarf—that keeps the disk from spreading outward, similar to how Saturn's moons shape the edges of some of the planet's rings."The story of how you make a ring around a planet could be the same as the story of making rings around a star," ...Seems a bit of a reach to me. If companion star has enough gravity to cleanly empty the solar debri disk, why is it not at least perturbing the orbit Pluto, or liberating the two newly discovered, relatively weakly bound moons of Pluto?

[John L]

I have to confess that I have been interested in this concept for almost 20 years. While most star systems are indeed binary systems, it is very likely that our system harbours a dark companion, such as a brown dwarf.

I realize that the competing theory of occilations along the galactic plain also has a great deal going for it.

My question to you is this: what is different about your theory from that which as been around for at least 20 years now?

And what are the latest pieces of information that support this theory? Personally, I like this one better than the "galactic plain" one, but I am inclined to believe it as being perhaps more plausable.

[John L]

Here is some of the latest information on the Nemesis theory that only came out yesterday. This article at Space.com (http://www.space.com/scienceastronomy/060119_kuiper_stars.html) adds more to the subject.

Sun's Nemesis?

Kalas and Graham speculate that stars also having sharp outer edges to their debris disks have a companion—a star or brown dwarf—that keeps the disk from spreading outward, similar to how Saturn's moons shape the edges of some of the planet's rings.

"The story of how you make a ring around a planet could be the same as the story of making rings around a star," Kalas said. Perhaps a passing star ripped off the edges of the original planetary disk, but a star-sized companion, remaining in place, would be necessary to keep the remaining disk material from spreading outward, he figures.

The scenario has Kalas and his colleagues thinking that the Sun might also have a companion that keeps the Kuiper Belt confined within a sharp boundary. U.C. Berkeley physics professor Richard Muller has proposed such a star, which he calls Nemesis, but no evidence has been found for one.

Here is an article about Dr Muller (http://www.space.com/news/nemesis_010410.html), who is probably the origionator of this theory. However, he proposes a red dwarf as the candidate. I would suspect it to be perhaps smaller, as in a brown dwarf. A red dwarf would be easier to find, as it's fusion process would be working, but only slowly. A Brown dwarf is a star that can't seem to get it's pants on.

And here is the article (http://hubblesite.org/newscenter/newsdesk/archive/releases/2006/05/image/a) from the Hubble site.

[TruthSeeker]

I know nothing about 2004 XR190, perhaps you will post more?

I think there are two possible explanations for Buffy's nearly circular orbit at 47 degrees to the ecliptic.

(1) Solar system stole it from some passing object (more than three bodies so not prohibited.) but the near circular nature of orbit forces a different conclusion:

(2) ETs made it! Back when it was too dangerous to colonize Earth as large meteor impacts were more common. Fact that it gets little solar energy at 57 AUs from sun, they considered to be an asset - their fusion reactors waste heat radiators worked better, but normally they point away from the sun so we have not yet detected the strong IR signature from that radiator (or they all died long ago and were nice enough to shut reactor down first - unlike those jerks who lived on the planet we now call the asteroid belt.).
;)
I believe the second option is more plausible......