A New Way to Find Earths

Jul 09, 2010
90-cm telescopes at the University Observatory Jena in Germany. Credit: AIU Jena

Astronomers have used a completely new technique to find an exotic extrasolar planet. The same approach might even be sensitive enough to find planets as small as the Earth in orbit around distant stars.

A team of astronomers from Germany, Bulgaria and Poland have used a completely new technique to find an exotic extrasolar planet. The same approach is sensitive enough to find planets as small as the Earth in orbit around other stars.

The group, led by Dr. Gracjan Maciejewski of Jena University in Germany, used Transit Timing Variation to detect a planet with 15 times the mass of the Earth in the system WASP-3, 700 light-years from the Sun in the constellation of Lyra. They publish their work in the journal .

Transit Timing Variation (TTV) was suggested as a new technique for discovering planets a few years ago. Transits take place where a planet moves in front of the star it orbits, temporarily blocking some of the light from the star. So far this method has been used to detect a number of planets and is being deployed by the Kepler and space missions in its search for planets similar to the Earth.

If a (typically large) planet is found, then the gravity of additional smaller planets will tug on the larger object, causing deviations in the regular cycle of transits. The TTV technique compares the deviations with predictions made by extensive computer-based calculations, allowing astronomers to deduce the makeup of the .

For this search, the team used the 90-cm telescopes of the University Observatory Jena and the 60-cm telescope of the Rohzen National Astronomical Observatory in Bulgaria to study transits of WASP-3b, a large planet with 630 times the mass of the Earth.

“We detected periodic variations in the transit timing of WASP-3b. These variations can be explained by an additional planet in the system, with a mass of 15 Earth-mass (i.e., one Uranus mass) and a period of 3.75 days”, said Dr. Maciejewski.

“In line with international rules, we called this new planet WASP-3c”. This newly discovered planet is among the least massive planets known to date and also the least massive planet known orbiting a star which is more massive than our Sun.

This is the first time that a new extrasolar planet has been discovered using this method. The new TTV approach is an indirect detection technique, like the previously successful transit method.

The discovery of the second, 15 Earth-mass planet makes the WASP-3 system very intriguing. The new planet appears to be trapped in an external orbit, twice as long as the orbit of the more massive planet. Such a configuration is probably a result of the early evolution of the system.

The TTV method is very attractive, because it is particularly sensitive to small perturbing , even down to the mass of the Earth. For example, an Earth-mass planet will pull on a typical gas giant planet orbiting close to its star and cause deviations in the timing of the larger objects’ transits of up to 1 minute.

This is a big enough effect to be detected with relatively small 1-m diameter telescopes and discoveries can be followed up with larger instruments. The team are now using the 10-m Hobby-Eberly Telescope in Texas to study WASP-3c in more detail.

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User comments : 5

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GSwift7
1.5 / 5 (2) Jul 09, 2010
That's prety cool, but I'm waiting for a good way to find any planets round the Centari system. My intuition says that Centari A-B contains at least one terrestrial planet. It would be really tantalizing to actually confirm it though.
PhysicsLver21
1 / 5 (2) Jul 10, 2010
That's prety cool, but I'm waiting for a good way to find any planets round the Centari system. My intuition says that Centari A-B contains at least one terrestrial planet. It would be really tantalizing to actually confirm it though.


I completely agree... why dont astronomers point their telescopes at stars which have strong connections to ancient cultures such as that of sirius or any star formations pointed out by the Sumerians where we believe aliens might have originated from? seems to me that if ancient civilizations looked at these constellations and say that extraterrestrials originated form certain stars those would be the first ones I would be studying... egyptians said that "sky people" originated from sirius.. look there and see what you find people come on!
Bob_Kob
not rated yet Jul 10, 2010
Plural of Earth? Earths or Earves?
FredJose
not rated yet Jul 10, 2010
The discovery of the second, 15 Earth-mass planet makes the WASP-3 system very intriguing. The new planet appears to be trapped in an external orbit, twice as long as the orbit of the more massive planet. Such a configuration is probably a result of the early evolution of the system.

AS a neophyte, I'd like someone knowledgeable to explain the implications of having these planets orbit like this.
It's not clear from the article and hence the accompanying explanation adds absolutely nothing to clarify the issue.
In fact it seems like there's a problem with having the planets orbits in this fashion which runs counter to what one would expect from theory - and so an ad-hoc explanation is thrown in to field any questions that might arise.
Please, someone, do provide some insight into the reason for the explanation.
Thanks.

Adriab
not rated yet Jul 12, 2010
@fredjose

The problem is the more we learn about planetary systems the more we see our theories for planetary system formation and evolution falling apart.

Its not just that we are wrong, that's easy, we incorporate new data and rebuild our theories. The annoying issue is that many of these new-found systems break our theories in new and interesting ways.

The theories are getting better, but we've got a ways to go yet.