Astronomers find 'home from home' - 90 light years away!

spaceref.com ^ | 3 Jul 03 | staff

[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.

[ALS]

"We might expect to find microbial life everywhere, or we might not. We won't know anything until we get out there and take a look, so we better get moving. Daylight's burning."

precisely

[Physicist]

Save your insults for that morning shave in front of the mirror.

Prof. Brimley's comment, far from an insult, is the most cogent comment on fine-tuning arguments ever uttered by human tongue. The world isn't "just right" for us: we are right for the world, because evolution has naturally shaped us to conform to it. We are so in tune with the properties of our world that they look like prerequisites.

[Prodigal Son]

So what you're telling me is physics, astonomy- all that is now defunct? All I need is biology? Biology is literally the study of life. Stars, dark matter, black holes- none of these things live. They are outside the domain of biology. When did biology trump all the other sciences? This must have happened in the last few minutes- literally. It's the very first I've heard of it.

[Prodigal Son]

It is not evidence there is life elsewhere.

But it is evidence of life in the universe- yes or no? We are part of the universe yes? And since it is evidence of at least some life in the universe it constitutes this "snitch of evidence" you were referring to. No matter how small the evidence is- it exists. This is totally different than saying no evidence at all exists.

[ALS]

Your problem seems to be with free speech/thought.

Odd for someone who hangs around a message board.

[ALS]

"But it is evidence of life in the universe- yes or no?"

absolutely

Any stretch of that is just that, a stretch.

i.e. - an assumption

[Prodigal Son]

Your problem seems to be with free speech/thought.

Now this is an assumption.

[Prodigal Son]

Has there ever been life elsewhere in the solar system other than Earth?

[balrog666]

Prof. Brimley's comment, far from an insult, is the most cogent comment on fine-tuning arguments ever uttered by human tongue. The world isn't "just right" for us: we are right for the world, because evolution has naturally shaped us to conform to it. We are so in tune with the properties of our world that they look like prerequisites.

Wilfred Brimley wisdom echo.

[ALS]

"Your problem seems to be with free speech/thought.

Now this is an assumption."

Agreed

[ALS]

When I get my rocketship finished and traverse it, you'll be the first to know what I find.

[Prodigal Son]

I'm asking you now though. As far as you know- has there ever been life elsewhere in the Solar System other than on Earth?

[e_engineer]

The Extrasolar Planets Encyclopaedia 30 June: 7 new planets: Looks like elliptical orbits of eccentricity .3 are common.

You have made the most interesting observation on the thread so far. Why 0.3 eccentricity?

Is it favored by the detection method?

[RightWhale]

Stars, dark matter, black holes- none of these things live.

Consider that they have the same stuff as life, but not of the same order of complexity. All the prerequisites for consciousness, cell structure, and society already exist in the subatomic particles. The complexity isn't there, so the higher attributes don't manifest, but the forces and energy are there in a less organized form. Simple evolution, the basics are there already, but it's too hot or too cold, or too wet or too dry in all cases except for us on earth. Goldilocks and the three bears: this porridge is just right. That's us--Goldilocks. Cosmic truth in a child's nursery tale.

[ALS]

You already know the answer, so what's your point, unless you are not being forthcoming about your definition of life.

[Lawgvr1955]

That is very close, but take the lap years into consideration then the length of the year is 365.242198 days and not 365.

If you want to be that accurate you shouldn't use 186,000 miles per second. I believe the speed of light is closer to 186,284 miles per second. Plus there is some controversy whether the speed of light has remained constant throughout time.

http://www.ldolphin.org/cdkconseq.html

[Prodigal Son]

I still don't follow this postulate. The planets and stars could exist even if life existed nowhere. Therefore, the entire science of biology could be excised from the universe and the universe would be pretty much like you observe it through your telescope.

However, if you withdrew the laws of physics, everything changes. Nothing is possible as we now see it or understand it.

Evolution could be totally disproved without upsetting the laws of the universe as we know them. This to me indicates that biology is a mere subset of the truth- not the complete picture. I just don't see what biology has to do with this big planet we have found.

I guess I'm just stupid.

[Prodigal Son]

You already know the answer,

Assumption on your part. It's a really simple question. It was a yes/no question. You don't have to answer it.

unless you are not being forthcoming about your definition of life.

Intelligent life. Why not? As far as you know, has intelligent life ever existed in the Solar System other than on planet Earth?

[ALS]

physical life?

not that anyone has seen

have you?

[petuniasevan]

Thanks for the ping, RightWhale.

For you non-astronomers out there, realize that we do NOT see the planet in orbit around its star. That would be like finding a firefly circling a bank of floodlights.

Instead, astronomers carefully plot a star's movement (proper motion). If the star seems to wobble, that is carefully measured and the mass of the unseen object is inferred from the interplay between the two objects. Incidentally, the star's mass is determined the same way.

This process can take years of exacting, precise measurements and careful data interpretation. Don't want to forget to factor in Earth's own movement (yes, that did happen - embarrassing to all involved).

Stats for this star:

HD70642 --- RA 08:21:28 dec. -39:42:21 magnitude 7.17

RA is Right Ascension (longitude) and dec. is declination (latitude) projected onto the sky. Magnitude is apparent brightness. It is a logarithmic scale of brightness, with lower numbers being brighter. The dimmest naked-eye magnitude under excellent conditions varies according to visual acuity, but averages about magnitude 6.

I'll take this opportunity to show where the constellation Puppis (the Stern) is. If Canis Major is visible (Look for brilliant star Sirius) to the left of Orion, then Puppis is to the lower left of Canis Major.

The bright streak is an overexposed Sirius.