Amateur astronomers discover a planet with four suns

http://io9.com/5951865/unprecedented-amateur-astronomers-discover-a-planet-with-four-suns?utm_source=lifehacker.com&utm_medium=recirculation&utm_campaign=recirculation

by boh • 14 years ago

116 37 14 years ago

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tocomment2• 14 years ago

Any chance someone could make a diagram of the orbit for us? I really can't picture this? Does it make a figure 8 around the first two stars?

InclinedPlane6• 14 years ago

It's a pair of binary stars with a planet orbiting one pair.

To give you a conceptional model, imagine that Mercury is a star and then imagine that, say, Saturn and one of its moons are also stars. Now, obviously, orbital mechanics are going to change when you have all of these much more massive bodies in the system, but hopefully you get the picture.

Edit: obviously not to scale, but maybe this helps: http://i.imgur.com/RJrOw.png

jmilloy2• 14 years ago

Your parent is asking how the planet orbits two stars, and probably how the 2-star-1-planet system orbits the two other stars. That is, "how does any body orbit two stars?"

tocomment2• 14 years ago

Thanks. That is helpful. So there's no scenario where a planet could be in a figure 8 orbit? That would be amazing.

jmilloy2• 14 years ago

It's probably similar to other two-sun planets. The planet orbits around both stars at the same time, which are close together. http://galileospendulum.org/2011/09/15/a-planet-with-two-sun...

SoftwareMaven2• 14 years ago

The point the earth actually orbits around isn't actually in the middle of the sun. It is at the center of mass between us and the sun. A planet orbiting a dual star system will do the same thing, but the center of mass winds up being somewhere between the two stars.

DanBC2• 14 years ago

They were using Planet Hunters - which appears to be a crowd sourced "find interesting bits in all this data" website. (http://planethunters.org/)

bdisraeli• 14 years ago

I work for the group that made Planet Hunters. We have a variety of similar projects at http://zooniverse.org, including four others we launched in the last month that have people classifying sea floor life, galaxies, cyclones, and bat calls.

DanBC2• 14 years ago

They're very cool projects! I've been noodling around for a bit.

I'll register if I think I'll be any good, and I'll certainly be passing the URLs around to people if I think they'll be interested.

ajasmin• 14 years ago

Could someone explain how that site works?

Are the amateur astronomers mentioned in the article user of planethunters.org who just happen to have been served the right pictures to work on? Is this Mechanical Turk type work or does it require serious scientific effort?

prima-facie• 14 years ago

Man, everything has to be quad core these days.

zandorg• 14 years ago

Overheating too, I guess.

twmb• 14 years ago

I wonder if it's a planet such that the surrounding stars' lights prevent any other starlight from being seen, except for once every few thousand years.

One could only imagine a civilization that lives here and what would happen to society whenever the full night sky is occasionally seen...

thanosbaskous• 14 years ago

I know that you're being fatuous but in case anyone doesn't get the reference, check out Nightfall by Asimov - it's a classic sci-fi short story.

http://www.uni.edu/morgans/astro/course/nightfall.pdf

DougWebb• 14 years ago

The planet is a Neptune-like gas giant, so no civilization there. It probably has big moons though, and with all the suns around they might be warm enough to develop life. I haven't done the math, but I'm guessing that when the moon is on the night side of the planet relative to the nearby stars, the location of the distant stars would cycle in basically the same way Jupiter does in our sky. It moves slowly relative to the background stars, but still rises and sets every day.

I don't know the details and couldn't do the math if I did, but I'm guessing those stars at 1000AU can't be much brighter than our full moon is, maybe combined with the light pollution of a big city. I've lived outside of New York all my life, and my night sky still has stars in it. Not many, but enough to know they're there, and sometimes on a clear night I can see quite a few.

pdonis2• 14 years ago

> I'm guessing those stars at 1000AU can't be much brighter than our full moon is

They may well be fainter. According to Wikipedia, the Sun is about 400,000 times as bright as the full moon, on average:

http://en.wikipedia.org/wiki/Apparent_magnitude

So if the Sun were 1,000 AU away from us instead of 1 AU, it would be a million times fainter (1,000 squared), or less bright than the full moon.

sliverstorm• 14 years ago

The planet is a Neptune-like gas giant, so no civilization there.

The gas creatures beg to differ.

b_emery• 14 years ago

Their link to human vs machine is interesting:

http://www.planethunters.org/science#human

I wonder how good their machine learning is? I'd love to throw some support vector machines or neural networks at this stuff!

sadga• 14 years ago

A team at McGill made a "game" to find patterns in I think protein-folding or genome data, to leverage humans to identify patterns that their algorithms could not.

http://en.wikipedia.org/wiki/Phylo_(video_game)

InclinedPlane6• 14 years ago

I tracked down the original paper (http://arxiv.org/abs/1210.3612) and dug up some useful details.

The planet in question is a gas/ice giant similar to Uranus with a radius 6 times that of Earth (nearly 80,000 km in diameter) with an as yet unknown mass (although it must weigh less than half of Jupiter's mass at the most). It orbits a pair of binary stars with a period of 138 days. The binary it orbits is an F dwarf star with 1.5 the Sun's mass and an M dwarf with 40% of the Sun's mass, they orbit each other with a period of 20 days. For reference, this translates to the two stars orbiting much closer than Mercury's orbit (around 0.17 AU) and the planet with an orbit close to that of Venus (around 0.65 AU, according to my calculations).

This system is bound to another binary system of similar total mass (a G2 star similar in mass to our Sun and an M2 dwarf star with around half or less the mass of our Sun) at a distance of around 1,000 AU. At that distance the second binary system would merely be the brightest stars in the night sky of the planet. The two binary systems would orbit each other with a period of tens of thousands of years.

ChuckMcM2• 14 years ago

I've tried about 8 different ways to modelling that and so far all of them have the planet being ripped apart as soon as its orbit is elongated by the traversing between the two pairs of binaries. Bizarre doesn't begin to describe it.

JoeAltmaier2• 14 years ago

Maybe the orbit is perpendicular to the stars' plane of orbit?

InclinedPlane6• 14 years ago

This doesn't make sense to me. The two pairs of binaries are around 6 light-days apart. The gravitational forces they have on each other are miniscule, but they are persistent enough to cause the two systems to orbit each other with a period longer than the duration of human civilization.

pm• 14 years ago

Brian Aldiss referenced a similar kind of system in his Helliconia science fiction trilogy, where a planet orbited a small sun, which in turn orbited a much larger sun in a much longer orbit.

Ironically, truth turns out to be stranger than fiction, seeing as this two binary systems are involved.

Amateur astronomers discover a planet with four suns

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