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4-inch Telescope Finds New Planet
serutan writes "After a backyard astronomy size telescope first tracked the periodic dimming of a star 500 light-years away, the Keck I telescope in Hawaii later confirmed that a Jupiter-size planet orbits the star. A press release from Harvard gives details. This is the first result of the Trans-Atlantic Exoplanet Survey, a project using small telescopes and cheap equipment to search for extrasolar planets. "
My only question is, how does a backyard telescope track the periodic dimming of a star? To my eyes, the things dim and brighten -- twinkle, if you will -- pretty much constantly.
Err, wait, never mind. Just read the Harvard press release and the "It took several Ph.D. scientists working full-time to develop the data analysis methods for this search program," bit.
Cool.
--------------------- -me, Crusher of those who are Foolish (don't be foolish)
The Telescope did NOT find this planet. The Software did.
Nothing in the world is more dangerous than sincere ignorance and conscientious stupidity.
Yes -- thats why there's plans for a space telescope in the next 10 or 20 years to look specifically for terrestrial planets.
also, jovian planets are good info too. One strong hypothesis is that life couldnt exist on earth without a big planet (jupiter) out there sweeping up most of the space junk (asteroids, comets, etc) that comes falling into the solar system. Big planets help out the inner planets by keeping collisions down.
Moo.
Although it is Uranus-sized, it is close to the star, and so it may not be similar.
ESO press release: http://www.eso.org/outreach/press-rel/pr-2004/pr-2 2-04.html
Will this method help find smaller planets?
Almost certainly not. The amplitude of the brightness variations, caused by the transit of a terrestrial planet, varies as the square of the ratio between the radius of the star and the planet. For the Sun/Earth values, this figure comes out as a 0.008% variation in brightness, or -- in astronomical terms -- a change of 0.2 millimagnitudes.
Measuring such small changes is extremely difficult, even using very large (5-10m) ground-based telescopes that have fancy optics and a high throughput. That's why terrestrial planet finding using the transit method will have to wait for NASA's Kepler mission. Scheduled for launch in 2007, this mission will look for minute brightness variations in c. 100,000 nearby Solar-type stars.
Tubal-Cain smokes the white owl.
This really is a huge boost to amateur astronomy. All "size doesn't matter" jokes aside (gawd, that got old fast), an average amateur astronomer with a reasonably priced scope has a chance to find something new in space. That has to be exciting to anyone who looks up at the sky and wondered.
Who's gonna go get a scope now? I suggested Orion Scopes for price vs bells and whistles (if you are into the extra gadgetry and have the paycheck to not care about price, go Meade).
Good quote, too many chars. Seriously, the slashdot 120 char limit sucks!
As others have said, the telescope didn't find the planet, nor did it's owner. The software found the planet.
All stars "dim" or twinkle to a regular viewer, due to our atomsphere. If it were just atmospheric stuff, the dimming cycle should be pretty much random. But software can find a pattern in the "dimming" that a human couldnt. (The "cycle" would last months, if not years, would it not)
2 decades ago this software didn't exist.
I don't need no instructions to know how to rock!!!!
All well and good? You gotta be kidding me! Someone with a hobby telescope spots something like this and it's like a hole-in-one in golf. Maybe you're looking for your next home, but at this stage even the people with the big radio scopes are excited by a planet find.
Maybe when we are able to warp space or whatever we'll get close enough to most of these stars to find something puny like an Earth size planet. For the meantime keep in mind the only way we know these things are there is from observation of the stars they orbit -- at this distance an Earth or Mars would be very hard to detect.
A feeling of having made the same mistake before: Deja Foobar
Resolution isn't wasn't necessary to make this technique work. Even the best telescopes have trouble detecting stars as more than point sources.
What matters is the quantity of light recieved per unit time. With the proper equipment on the end, even a small telescope can accurately measure very precisely the amount of light it recieves. I imagine the tricky part is eliminating other factors such as local environmental conditions.
I rarely criticize things I don't care about.
There should be lots of resources on the web on how to make your own telescope.
unfortunately, to date, all the Jupiter size planets have had insanely close or insanely eccentric orbits which would preclude any terrestrial planets from forming in a habitable zone.
I am the Alpha and the Omega-3
Also, remember that most of the planets that are being found are being found because they are easier to find (more eccentric orbits, larger planets, etc.), planetary formation for these systems might also be different than average (close encounters with other stars early in star formation, stars more unstable than others, etc.)
"I recently looked at some straonomy pictures and saw images of galaxies far far away where you could see individual stars. Surely these galaxies are so very far away that they would cover no more of the sky than a star that is only a few lightyears away would? So why can we get such good images of them but not of individual nearby stars or planets?"
Unfortunately this is not so.
The angular size of a star is much smaller than the angular size of (say) the Andromeda Galaxy, which probably makes up a majority of the non-Milky Way pictures of galaxies that most people see.
A star is usually tens to hundreds of thousands of km across. There are a few exceptions, but for the most part this is true. A galaxy is tens to hundreds of thousands of light years across. That's about 10000000000000 times larger. However, a galaxy like Andromeda is less than a 100000 times more distant than they stars we're talking about. Therefore, we can see significant internal detail.
I rarely criticize things I don't care about.
I think it's mostly down to the fact that these large planets close to their parent stars are easier to see.
If you're looking at a Jupiter-sized object that orbits closer than Mercury, then you're going to have an orbital period on the order of days or weeks. On the other hand, if you want to detect a Jupiter-sized object orbiting at that same distance Jupiter does from our Sun, then your orbital period ends up as years or tens of years (Jupiter completes one orbit in a bit less than twelve years.)
Depending on the technique you use to detect a planet, you often need to show a pattern that persists through at least two or three consecutive orbits.
In the case discussed here, very small changes in brightness (less than 1%) were observed every time there was a transit (the planet passed between us and the other star); these events took place every three days. In principle, one could get sufficient data in a week or so. If we were looking at an object with an orbit like Jupiter's, we'd need to have at least a quarter century of careful monitoring of the star. Other techniques also require significantly more data collection time or more sensitive equipment as the planets get smaller and their orbits grow longer. The reason why we're detecting massive gas giants in close orbits is because they're the easiest planets to see. We're definitely not getting a random sample of all planets.
Yes, the planets we are seeing seem unusual, but they're still quite few in absolute number. Perhaps in twenty years when we can reliably start detecting rocky, Earth-type planets in Earth-type orbits we'll be able to make more definitive statements. Right now we're like biologists trying to understand human life--but only being allowed to study specimens weighing more than 600 lbs.
~Idarubicin
This method of looking for planetary transits will be tried on 100,000 stars simultaneously by the Kepler space probe in 2007. Kepler points a 95 megapixel camera at the same patch of the sky for several years. They expect to discover about 900 planets, of which 50 may be Earth-size. Their assumptions about planetary size distribution and detectability are given on their website.
You have some points but you're thinking a little too anecdotally. If something came at the earth from way outside the plane of the ecliptic, youre absolutely right that Jupiter couldnt do anything about it. It's a good thing that there's almost NOTHING way outside the plane of the ecliptic -- to come in at such an angle, it would most likely have been gravitationally deflected from something else. Most stuff to worry about comes in from the oort cloud, which is more amorphous than the kuiper belt or asteroid belt (hence the term cloud, not belt). Anything out of the belts will most likely be affected, or has been affected, by Jupiter at some point.
Now, as for something having to pass through Jupiter's orbit at just the right time, you're right -- its a big solar system. But the junk flying around doesnt fly very fast....and its not likely to hit anything. It's most likely to hit either the sun, or Jupiter, and thats the key. without the gas giants, all that junk is mostly likely to hit...earth.
Of course, stuff still does (ask the dinosaurs or the trilobytes) but at a low enough rate, and its small enough, that life can handle it.
Moo.
But... remember Reagan's "Star Wars" space defense progam? One of the very few useful things we got for all that money was a technology called "adaptive optics." Basically, technology that takes the "twinkle" and the "wobble" out of stars.
Just about everything optical (and maybe even infrared) on Mauna Kea has some AO ability nowadays, using tertiary mirrors that can be adjusted ("tip-tilt") or deformed many times per second by computer-controlled actuators, and/or Orthogonal Transfer CCD's co-developed by University of Hawaii and MIT.
I work a few nights a month on Mauna Kea, and have seen an OTCCD instrument (OPTIC) in use on UH's 88-inch telescope (which also has a simple tip-tilt system available, I think), and it's pretty neat technology. I'm hoping the technology will lead to better image-stabilization technology for photography and videography... and I'd also like to see it "trickle down" to amateur telescopes. :)