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.
Remember when a planet is orbiting a star; it also has a gravitational influence on that star as well. So it’s not just a planet orbiting a star, it's both orbiting a common center of mass.
So as the planet becomes more massive, the further the center of mass moves from the center of the star (causing the star to wobble).
Also the period of an orbit is directly proportional to its distance from the star, closer is shorter.
So the massive close-in higher elliptical planets are far easier to detect.
If a planet has a perfectly circular orbit, the center of mass of the system will rotate around the center of the star in a uniform fashion and usually does not cause the star to wobble enough to be detectable by our present method of stellar displacement.
So in conclusion, a massive planet with a close in higher elliptical orbit will cause an appreciable fast enough wobble that is easier to detect.
Physicist, longshadow, MikeD; All; Anything you want to add?
ROFL! (or too many bananas cause ME to speed to the local restroom) hehehehehe
yes.....
you didn't use the term "wildly elliptical" anywhere in your explanation.
;-)
Unfortunately I have this irresistable urget to post that comment; "Wildly Elliptical"in blue. Didn't want to distract from the explanation. hehehehe
Katherine Hepburn was older than that. Puts a reference into the timescale--one lifetime. One lifetime to get there at the speed of light, another lifetime to get back.
NASA scientists, starry-eyed dreamers that they are, are building a spaceborne telescope to spot earthlike planets. Launch in about 4 years. Another eartlike planet spotting telescope to follow a couple years later. And another. It won't be long, unless, of course, they don't find something.
Agreed.
So as the planet becomes more massive, the further the center of mass moves from the center of the star (causing the star to wobble).
Agreed.
Also the period of an orbit is directly proportional to its distance from the star, closer is shorter.
Agreed.
So the massive close-in higher elliptical planets are far easier to detect.
If you change this to read: "So the massive close-in higher elliptical planets are far easier to detect.", Agreed.
Imagine a Jupiter mass planet in a circular orbit with perihelion = 1 AU. If you could change it's ellipticity (sp?) but keep the perihelion (closest approach) at 1 AU, does it become easier or harder to detect based on the stars radial velocity?
Since the maximum excursion of the center of mass would be the same in both cases, the elliptical orbit would be (at best) equally detectable to the circular orbit.
If we assume that both orbits are in the same plane with the observer on earth, the elliptical orbit becomes more difficult to detect if it's semi-major axis is perpendicular to the line of sight to earth.
Hmmm.... Think of it this way. If the planet is highly elliptical, the star will also exibit a elliptical motion around the center of mass (greater wobble). If the orbit plane is exactly in line with our line of sight of the star, I agree detection would be much more difficult. However, if we are looking at it face on, the motions of the star becomes much more apparent.
You never do. Which makes you clueless and irrelevant.
I have done nothing here but ask you to justify a-historical statements you made. I suggest that it is better to be clueless and irrelevant than unapologetically dissembling and distracting, offering cites intended to mislead, rather than enlighten.
shoo fly
I rest my case, and return the complement.
If you don't wish to be reminded of your failures to support your contentions in any reasonably relevant manner, I suggest you cease engaging in conversation with me. I have asked you many times, politely, not to start contentless verbal ping pong with me and you have ignored my requests.
If you don't what to hear what I have to say, don't post to me.
It really doesn't seem like an outstanding bet, at this point. However, let me just point out that it isn't all that insurmountable a barrier to occupation of other solar systems. Generation ships will be able to do it, and a fully utilized solar system should be able to slingshot stuff at close enough to light speeds to make the Twin Paradox effect a useful relative life-span lengthener for those who travel, if not for those who stay on their mudballs. A few prudent investments might make a round trip to alpha proxima a darn good fiscal gamble--but, of course, all your friends and family will be long gone by the time you collect.
Get your friends and family whipping around the univese with you, and the story might change for the better. (at least from your point of view) Of course, mudball dwellers may be increasingly viewed as cattle in such circumstances.
Wallace was a very far ways down to same path Darwin trod, and for much the same reasons; he had consulted with Darwin, and he was very impressed with Darwin's excruciatingly detailed efforts, and was a generous and gentle soul. He happily shared the pre-publication early exposures of the theory as the junior of the two, recognizing that Darwin's efforts far outstripped his in detail and scope, if not speed to market.
Looking at relative publication dates, it would be fair to say the Wallace could have stolen a great deal of Darwin's thunder, if he had simply published what he had, when he had intended to. That he chose not to commends him to me very much in an age already heating up with scientific competitiveness.
However, be that as it may, that in no way makes Darwin's work plagarism, or anything even remotely resembling plagarism, nest paws?
Ah, still lurking about, trying to find someone to provoke, I see. OK.
Here is the only cite reference you have made here that I am aware of.
http://www.designeduniverse.com/als/notconservatism.html
Could you show me where in this is the demonstration that Darwin is a plagarist? Or where in this is a demonstration that because some fascists adopt Darwinism, therefore Darwinism is scientifically discredited? I'm sure it was merely an oversight that you have failed to do so up to now.
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