Posted on 07/03/2003 10:22:13 AM PDT by RightWhale
Astronomers find 'home from home' - 90 light years away!
Astronomers looking for planetary systems that resemble our own solar system have found the most similar formation so far. British astronomers, working with Australian and American colleagues, have discovered a planet like Jupiter in orbit round a nearby star that is very like our own Sun. Among the hundred found so far, this system is the one most similar to our Solar System. The planet's orbit is like that of Jupiter in our own Solar System, especially as it is nearly circular and there are no bigger planets closer in to its star.
"This planet is going round in a nearly circular orbit three-fifths the size of our own Jupiter. This is the closest we have yet got to a real Solar System-like planet, and advances our search for systems that are even more like our own," said UK team leader Hugh Jones of Liverpool John Moores University.
The planet was discovered using the 3.9-metre Anglo-Australian Telescope [AAT] in New South Wales, Australia. The discovery, which is part of a large search for solar systems that resemble our own, will be announced today (Thursday, July 3rd 2003) by Hugh Jones (Liverpool John Moores University) at a conference on "Extrasolar Planets: Today and Tomorrow" in Paris, France.
"It is the exquisite precision of our measurements that lets us search for these Jupiters - they are harder to find than the more exotic planets found so far. Perhaps most stars will be shown to have planets like our own Solar System", said Dr Alan Penny, from the Rutherford Appleton Laboratory.
The new planet, which has a mass about twice that of Jupiter, circles its star (HD70642) about every six years. HD70642 can be found in the constellation Puppis and is about 90 light years away from Earth. The planet is 3.3 times further from its star as the Earth is from the Sun (about halfway between Mars and Jupiter if it were in our own system).
The long-term goal of this programme is the detection of true analogues to the Solar System: planetary systems with giant planets in long circular orbits and small rocky planets on shorter circular orbits. This discovery of a -Jupiter- like gas giant planet around a nearby star is a step toward this goal. The discovery of other such planets and planetary satellites within the next decade will help astronomers assess the Solar System's place in the galaxy and whether planetary systems like our own are common or rare.
Prior to the discovery of extrasolar planets, planetary systems were generally predicted to be similar to the Solar System - giant planets orbiting beyond 4 Earth-Sun distances in circular orbits, and terrestrial mass planets in inner orbits. The danger of using theoretical ideas to extrapolate from just one example - our own Solar System - has been shown by the extrasolar planetary systems now known to exist which have very different properties. Planetary systems are much more diverse than ever imagined.
However these new planets have only been found around one-tenth of stars where they were looked for. It is possible that the harder-to-find very Solar System-like planets do exist around most stars.
The vast majority of the presently known extrasolar planets lie in elliptical orbits, which would preclude the existence of habitable terrestrial planets. Previously, the only gas giant found to orbit beyond 3 Earth-Sun distances in a near circular orbit was the outer planet of the 47 Ursa Majoris system - a system which also includes an inner gas giant at 2 Earth-Sun distances (unlike the Solar System). This discovery of a 3.3 Earth-Sun distance planet in a near circular orbit around a Sun-like star bears the closest likeness to our Solar System found to date and demonstrates our searches are precise enough to find Jupiter- like planets in Jupiter-like orbit.
To find evidence of planets, the astronomers use a high- precision technique developed by Paul Butler of the Carnegie Institute of Washington and Geoff Marcy of the University of California at Berkeley to measure how much a star "wobbles" in space as it is affected by a planet's gravity. As an unseen planet orbits a distant star, the gravitational pull causes the star to move back and forth in space. That wobble can be detected by the 'Doppler shifting' it causes in the star's light. This discovery demonstrates that the long term precision of the team's technique is 3 metres per second (7mph) making the Anglo-Australian Planet Search at least as precise as any of the many planet search projects underway.
True. I don't have any steadfast opinion either way, I was just trying to post a link that had some of the arguments. (I couldn't get the address to hyperlink. Guess my html skills are lacking. Suggestions for posting links would be appreciated)
Personally, I am trying to get a government grant to study the speed of dark. Check out the link I tried to post.
http://www.ldolphin.org/cdkconseq.html
Otherwise you have to use this formula:
<a href="http://www.ldolphin.org/cdkconseq.html">http://www.ldolphin.org/cdkconseq.html</a>
Yes. We have crossed to a new level, crossed a kind of discontinuity. Before this we knew of no other solar systems like ours, now we know of one other that superficially, anyway, looks like ours. Doctoral theses, Sunday sermons, and youthful plans for college are being revised today. Last year they found huge amounts of water on Mars, but in all honesty the excitement was diffuse. Maybe this discovery will fire the imagination of our collective selves. Or not.
Frog eyes are more advanced than ours, they have a sensor like our cones and rods but that senses dark.
If we weren't just right, we wouldn't be having this conversation.
The least massive planet was 0.1 Jupiter mass, which is to be expected based on the detection methods.
The planets of our solar system have eccentricities ranging from .01 (Venus) to .25 (Pluto). 70% of the extra-solar planets have eccentricities greater than Pluto's.
If we only compare our giant planets, with eccentricities ranging from 0.01 (Neptune) to 0.06 (Saturn ) the difference becomes more dramatic. 80% of the extra-solar planets are more eccentric than the giant planets of our system.
This suggests that our system is the exception, rather than the rule.
We might expect that systems where the main planet's orbit has high eccentricity would be tough systems to have other planets that might be interesting to us. Pluto is thought to be an escaped moon from Neptune, and Pluto's orbit takes it inside Neptune's orbit and then farther out. Right now Pluto is nearer the sun than usual so NASA wants to send a probe out there to see what is happening on Pluto when it is a little warmer.
There might be a mechanism that circularizes orbits in some systems that would be lacking in other or in most systems. Our solar system is dominated by fairly circular orbits: planets, and most moons, and the rings of Saturn and the other gas giants. It could be the interaction of several planets or moons creates the circularisation and those systems with one or two wild major planets lacks smaller rocky planets altogether. This one today might be judged to have more planets just on the basis of circular orbit of the major planet.
It will be the greatest adventure since we got the boot from the Garden. Noah was just warmups.
I think that "The Wildly Elliptical Orbits" would be a great name for a rock band...
You were on all 3 too. What's your point?
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