Skip to comments.Mass limit on Nemesis
Posted on 08/03/2006 9:24:16 PM PDT by SunkenCiv
We assume that if the sun has a companion, it has a period of 27 Myr corresponding to the periodicity seen in cometary impacts on earth. Based on this assumption, it is seen that the inner Lagrangian point of the interaction between the Sun and its companion is in the Oort cloud. From this we calculate the mass distance relation for the companion. We then compute the expected apparent magnitude (visible and J band) for the companion using the models of Burrows... We then compare this with the catalogue completeness of optical and infrared catalogues to show that the sun cannot have a companion of mass greater than 44 M jup (0.042 M)... We estimate the error in this limit as follows. Since the periodicity in the geological records is 27 million years, the sum of the perihelion and aphelion distance must be 180,000 AU from Kepler's laws approximated for a low mass companion. Hence, if the object is in a highly elliptical orbit, the farthest the object can be, is 180,000 AU from the Sun. If the object is presently at its aphelion distance, then the apparent brightness will be a factor of 4 less than the value calculated here, effectively increasing the apparent magnitude by 1.5... Lopatnikov et al... estimate the Oort cloud mass to be about 300 earth masses (about 0.95 M jup), while in more recent work of Weissman... estimates the Oort cloud mass to be about 38 earth masses (0.12 M jup). We note that this mass will be distributed through the entire Oort cloud. So, its influence on the orbit of a companion of > 40 M jup... can be neglected safely.
(Excerpt) Read more at ncra.tifr.res.in ...
The other day I was looking for something newer (read in a magazine) and found this.
It possible that the Sun has a "dark" companion out there. Majority of the stars in the Galaxy are members of a binary group.
That's just what they're trying to figure out here. Nemesis was suggested not long after the emergence of the Alvarez model, and while there have been some limited attempts to look for such a body, it hasn't been systematic or thorough. The recent article I mentioned above has a nice discussion of this.
It a great article.
[Raup originally proposed the idea in a 1984 with University of Chicago colleague Dr. J. John Sepkoski]Nemesis, the Sun's companion star, 1983-presentThis hypothetical "death companion" of the Sun was suggested in 1985 by Daniel P. Whitmire and John J. Matese, Univ of Southern Louisiana. It has even received a name: Nemesis. One awkward fact of the Nemesis hypothesis is that there is no evidence whatever of a companion star of the Sun. It need not be very bright or very massive, a star much smaller and dimmer than the Sun would suffice, even a brown or a black dwarf (a planet-like body insufficiently massive to start "burning hydrogen" like a star). It is possible that this star already exists in one of the catalogues of dim stars without anyone having noted something peculiar, namely the enormous apparent motion of that star against the background of more distant stars (i.e. its parallax). If it should be found, few will doubt that it is the primary cause of periodic mass extinctions on Earth...However, since the examination of the entire sky in the far IR by IRAS with no "Nemesis" found, the existence of "Nemesis" is not very likely.
The Nine Planets
I agree with you. There has not been any evidence of it. There still teaching it though in astronomy classes.
this is neat:
Glosary [sic] from Astronomy knowledge base
Yes, alas, the bits of solar system debris which smack into the Earth once in a while seem to be drawn from the NEOs. There is no real pattern to it, at all, no cycle. Eugene Shoemaker thought that the apparent cycle was due to the solar system's circuit around the galactic axis, that somewhere there was a bunch of crud we'd pass through. The question I'd have is, why doesn't that bunch of crud also make the circuit? I don't think E.S. thought that through very well.
Eugene Shoemaker though was a great astromomer. It is ashame that he did not have the chance to walk on the Moon.
I think his wife wound up an astronomer; he was a professional geologist, but Barbara and Eugene, with David Levy, owe their fame to the SL-9 impacts on Jupiter.
AFAIC, periodicity in impact-caused extinctions are just a way to make catastrophe behave itself by being less random and more predictable. It's possible that the Sun has a companion, but if so, such a massive quasi-planet would have swept the outer solar system clear of debris a very long time ago.Nemesis: Does the Sun Have a 'Companion'?Richard A. Muller... a physicist at University of California at Berkeley... [has] ideas... generally rooted in solid science and genius extrapolation... But Muller's biggest idea is a real Nemesis. Or so he claims. Like a thorn in the side of mainstream researchers, Muller's Nemesis theory -- that our Sun has a companion star responsible for recurring episodes of wholesale death and destruction here on Earth -- seems to reemerge periodically like microbes after a mass extinction. It's a theory that has many detractors. And it's a theory that has been beaten down and left for dead in the minds of most scientists... Muller's idea for Nemesis came to him 1983. Luis Alvarez, then an emeritus professor of physics at the University of California at Berkeley, and his son Walter had recently put forth the theory that a giant impact had wiped out the dinosaurs... Around the same time, two other researchers had suggested yet another controversial idea, that mass extinctions occurred at regular intervals -- every 26 million years or so. Scientists immediately folded the ideas into a new and breathtaking possibility: Impacts by space rocks were causing massive global species destruction every 26 million years.
by Robert Roy Britt
03 April 2001
Unlike the paleontological record, the [geomagnetic] reversal record is fairly clean, at least for the past 165 million years of geologic time. About 300 complete reversals have been found in this interval, most well dated. There are smoe very long-term trends in the number of reversals per million years, and these have been known and accepted for many years -- even though there are no good explanations for them... I was encouraged to find a recent paper claiming periodicity in the number of reversals through time... J.G. Negi and R.K. Tiwari... concluded that there is a 32-million-year periodicity... a French group, headed by A. Mazaud, claimed a 15-million-year periodicity positioned in time such that every other pulse was a bit stronger and fell approximately at one of our extinctions... On the other hand, the problem had been looked at by a number of other geophysicists over the years... They had been unable to reject a hypothesis of randomness... I found an impressive 30-million-year periodicity that matched the extinction periodicity fairly well... Nature... neither accepted nor rejected the paper but returned it to me (with the reviews) to revise and resubmit. At the same time, I was invited to suggest the names of six additional reviewers. [pp 183-185]Dr. David RaupFor a while, I thought mass extinctions were merely instances of chance coincidence of independent species extinctions. That clearly was wrong... I have come to the view that large-body impact is responsible for far more extinctions that we appreciate -- perhaps including those pulses of extinction that usually define stratigraphic stages. Maybe even zones? ...For periodic extinction, I know of 13 complete re-analyses of the Sepkoski data that have been published by independent investigators. Of these, five found our periodicity to be significant whereas eight found no significant periodicity. Had these studies used the new genus-level data, I suspect periodicity would have fared better. In any event, the periodicity of extinction must, I think, remain an open question until we have either more data or data of a completely different kind... I believe they really are periodic but I cannot prove it. One problem is that in time-series analysis, one can establish a departure from randomness rather easily but proving a particular periodicity within that is nearly impossible... The extinction record has been analyzed about as thoroughly as possible and searches for Nemesis have failed to find the companion star... I think periodicity is on the back burner but not forgotten -- any more than continental drift was forgotten.
interviewed by Steve Brusatte
Dino Land Paleontology
I wasn’t looking for this oldie at this time, and had forgotten it (I don’t have the heart to look at the number of posts I’ve made on FR, or the number of topics I’ve started on FR), but it pertains to Raup and the periodic mass extinction thing. :’)
The grad student that did his periodicity research died very young, a shame. It confirmed my theory that gradualist's suck.
The idea of periodicity is really just a way to try to get catastrophes — which happen at random intervals — to behave themselves under uniformitarian gradualist paradigm. That’s probably why it didn’t catch on with *anyone*. :’)
Heh... I looked, it’s there on the shelf, wild! And it was filed next to the Officer and Page book (picked that up off remainder) which purports to prove that the dinos COULD NOT AND DID NOT go extinct as a result of an impact. :’) I moved it over one with a Gribbin book as a buffer.
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