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back to article Sun’s lost cousin may be to blame for wonky ecliptic

Sol may have had a near stellar neighbour at the time earth was formed, and its gravity could be the reason that planets in our solar system don’t orbit neatly around the Sun’s equator. That’s the thrust of a new letter in Nature, titled A primordial origin for misalignments between stellar spin axes and planetary orbits. …

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Sounds like Nemesis all over again

A lot of people have been very dismissive of the Nemesis hypothesis over the years but personally I've always found it unlikely, but been unwilling to entirely rule it out. You do the sums and a red dwarf could in fact be very close by, but next to impossible to distinguish from all the other background stars.

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Re: Sounds like Nemesis all over again

"a red dwarf could in fact be very close by, but next to impossible to distinguish from all the other background stars."

I thought the issue was that "Nemesis" was a *Brown* Dwarf which is so dark it couldn't be seen (a red dwarf that close to us could be seen fairly readily).

Mind you, that theory was put forward by Nemesis scientists *after* a wide scan of our immediate cosmos was performed and scientists found absolute diddly-squat.

Call me skeptical :-)

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Re: Sounds like Nemesis all over again

Both red and brown dwarves have been proposed at different points. The brown dwarf alternative is increasingly difficult to defend since infra-red sky surveys should have picked it up by now. The red dwarf alternative is much more difficult to dismiss since a nearby red dwarf to all intents and purposes looks identical to a much more distant red giant. To distinguish between them needs full spectroscopy of each candidate star individually, which is both costly and time consuming.

The magnitude range for a red dwarf has been estimated at between 9 and 12. That covers millions of stars. You can dismiss a lot of those immediately because they are the wrong overall colour (i.e. not red) but it still leaves you with tens to hundreds of thousands of possible candidates.

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Re: Sounds like Nemesis all over again

The red dwarf alternative is much more difficult to dismiss since a nearby red dwarf to all intents and purposes looks identical to a much more distant red giant. To distinguish between them needs full spectroscopy of each candidate star individually, which is both costly and time consuming.

Wouldn't distinguishing between a nearby dwarf and a distant giant just need two observations to be made, approximately 6 months apart?

"These stars are small. The ones out there are far away."

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Re: Sounds like Nemesis all over again

I am no expert but if boffins can locate a rogue planet without a sun in interstellar space. Which apparently they can. So I was informed yesterday on El Reg, with this planet being CFBDSIR2149 which four and seven times the mass of Jupiter and 100 light years away. Then I think a nemisis, nibiru or planet x would probably have been spotted by now. It's still a cool story though and I wonder if any data still shows any signs that mass extinctions are in any way periodic.

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Re: Sounds like Nemesis all over again

No, as I said, do the sums. That is all that is needed for a parallax measurement of a single star. According to the Tycho-2 catalogue here there are 5,227,058 stars between 9th and 12th magnitude. That makes 10,454,116 observations which is obviously a very small needle in a very large haystack.

Look at the list of nearby stars - they were generally detected not by parallax but by proper motion, and parallax only then used to measure the distance to the star in question, i.e. once it had already been identified. The problem with Nemesis is that it would have the same proper motion as our own solar system, and therefore not moving with respect to us, save for a very small orbital movement which to all intents and purposes looks the same as a much more distant star.

As for the detection of that brown dwarf recently that is precisely what I alluded to in my earlier post: you can detect those "easily" by looking for a bright IR source with no corresponding visible source. You can't do that for stars on the main sequence.

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Bronze badge

Techuestion

Does anyone know at which points/on which dates in the calendar year Earth's orbit crosses the plane of the ecliptic? And in which direction (e.g. 'upward, toward Polaris') it's moving on those dates?

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Anonymous Coward

Re: Techuestion

From the article: "Earth orbits about seven degrees away from the Sun’s equatorial plane, in what has come to be known as the ecliptic plane"

Earth's orbit /defines/ the ecliptic plane, it is always in it.

However, s/ecliptic/equatorial/ and you raise an interesting question. Anyone?

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Re: Techuestion

Not certain that "in what has come to be known as the ecliptic plane" should refer to the plane implicit in "Earth orbits...". Proximity, in the sentence, of "ecliptic plane" to "equatorial plane" suggests that the latter refers (as synonym) to the former.

What's what? This:

http://www.universetoday.com/35012/plane-of-the-ecliptic/

just confuses the issue--especially when viewed in close temporal proximity to this:

http://hyperphysics.phy-astr.gsu.edu/hbase/eclip.html

Ack! I'm going around in circles. Getting dizzy. It's getting dark...

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FAIL

And the rest!!!

"Humanity has, to date, observed just one other multi-planet solar system, Kepler 30"

There are 126 known multi-planet systems.

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Stop

Re: And the rest!!!

How many of those have been observed, to the extent where their ecliptic plane is known, rather then just detected?

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Anonymous Coward

Re: There are 126 known multi-planet systems.

There are 126 known *to humans* multi-planet systems.

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This does not make sense

"Author Konstantin Batygin contends that as stars often appear in clusters "

"Batygin believes the planet responsible for tugging Earth into its odd orbit is still out there somewhere. So are lots of exoplanets that may prove his theory."

So is it a star or a planet?

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Re: This does not make sense

That was a close finish :)

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" ...the planet responsible for tugging Earth into its odd orbit ..."

I thought the theory states that a (used to be) nearby star did it?

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Alien

OMG! Planet X!

This could well be the mysterious Planet X Niribu from the wierd neighbourhood at youtube.

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