View Full Version : Extrasolar Planets

2003-Jul-22, 09:34 AM
I believe that the discovery of a planet orbiting 51 Pegasi in 1995 kick-started one of the most exciting aspects of modern astronomy. Please use this topic to discuss your thoughts, theories etc. on the extrasolar planet discoveries and their implications.

Also, here are some excellent links (I posted them elsewhere in this forum but it wasn't a very popular topic).

The most up-to-date list of extrasolar planets on the internet. Updated most days.

A wonderful extrasolar planets site with hard data, great artwork, and some inspiring speculative material.

Another great extrasolar planets site.

Kashi B)

2003-Jul-22, 07:33 PM
This new era of planetary discovery is easily the coolest thing going in astronomy right now. I don't know what else to say. The only thing that's going to top this is when some of the terrestrial planet finding observatories start launching at the end of this decade. I can't wait until the first data starts coming back where they're measuring the atmosphere of Earth-sized planets orbiting other stars. If we find an oxygen-filled atmosphere relatively nearby, it's going to be a monumental discovery - easily one of the most important discoveries in all of science.

And we're only a few years away. It's extremely exciting.

2003-Jul-22, 08:35 PM
these discoveries are great and are one of those which invited me personally to hook up (let's not say get obsessed) with SPACE.i think it's getting kinda boring to keep on detecting gaseous or jupiter like planets tens of times the mass earth every second.the coming years are incontrovertibly substantial to enter the new era of earth-like planets detection.

however, after research, jupiter like planets, in general, play an important role in the formation or existence of earth like planets. one of the things they do is forming a huge gravity well that protects possible earth like planets from ASTEROIDS impacts,this is proved by the asteroid field b/w jupiter and mars, imagine what would have happened to earth if jupiter haven't existed. the gravity well also contributes in preventing the smaller planet from getting engulfed by the outgrowing star's gravity.
Jupiter like planets, if not too close to their parent stars, do help a lot in pointing to earth-like planets in that same system.So i guess we shouldn't get annoyed by the increasing nb of jupiter-like exoplanets as long as they don't orbit their stars at a distance less than 3.5AU.

2003-Jul-22, 09:23 PM
The first extrasolar planet around a Sunlike star was indeed the one found around 51 Pegasi in 1995. But let's not forget that the FIRST extrasolar planets were found by Alex Wolszczan and Dale Frail in 1991, orbiting the pulsar PSR B1257+12. Two of this pulsar's planets are just a few times more massive than the EARTH. A third planet, discovered in 1993, is comparable in mass to the MOON. An update on this pulsar's planets appears on pages 18-19 of the September 2003 issue of Sky & Telescope (it unfortunately gets the discovery date of the planets wrong).

2003-Jul-23, 12:30 AM
A universe teeming with worlds! Until only a few years ago it was hottly debated whether other planets existed at all. At least we have a better idea now of which way to point our hails! Perhaps we'll also find a universe teeming with life! ahh teh possibilities!!

2003-Jul-23, 09:31 AM
True true "Magenta". It's also interesting that the detection of planets didn't get any mainstream media attention until Marcy and Butler at San Francisco University found the 2nd and 3rd planet (around a main sequence star), after which they appeared on the cover of Time. I'd love to get a copy of that issue...I wonder how I would go about tracking it down.


2003-Jul-23, 10:43 AM
[QUOTE]Jane Platt 818/354-0880
Jet Propulsion Laboratory, Pasadena, Calif. July 22, 2003

Spotlight: Tiny Measurement Gives Big Boost to Planet Hunt

Even though astronomers have discovered more than 100 planets around stars other than the Sun in recent years, the "holy grail" of the search -- an Earth-sized planet capable of supporting life -- remains elusive. The main problem is that an Earth-like planet would be much smaller than any of the gas giants detected so far (see illustration at right).

Planets orbiting other stars are too dim to be observed directly, but scientists infer their presence by the tiny gravitational "wobble" they induce in their parent stars. Observed from tens of light years away (one light-year is 5.88 trillion miles), this movement becomes very tiny indeed. The smaller the planet, the less the star parent wobbles.

To detect the stellar wobble caused by a planet as small as Earth, scientists need an instrument of almost unbelievable sensitivity -- one that could measure an angle just one-tenth the width of a hydrogen atom. That's about 1 millionth of the width of the thickest human hair.

Or look at it this way: Let's say there's an astronaut standing on the moon, wiggling her pinky. You'd need an instrument sensitive enough to measure that movement from Earth, a quarter million miles away.

Is such precision possible? After a six-year struggle, engineers at the Jet Propulsion Laboratory recently proved that the answer is yes.

Such sub-atomic measurements were conducted for the first time ever within a vacuum-sealed chamber called the Microarcsecond Metrology Testbed.

By doing this, the engineers proved they can measure the movements of stars with an astonishing degree of accuracy never before achieved in human history.

The testbed, which resembles a shiny silver submarine, is jammed with mirrors, lasers, lenses and other optical components. Because even small air movements can interfere with the measurements, all air is pumped out of the chamber before each experiment is run. Laser beams, moving mirrors and a camera are used to help detect movements of an artificial star, which simulates the light that would be emitted by a real star.

The instrument that engineers have demonstrated in the laboratory will become the heart of a revolutionary new space telescope known as the Space Interferometry Mission.

"Six-and-a-half years ago, this technology was unproven and unsubstantiated," said Brett Watterson, the mission's deputy project manager. "It was just a remote possibility that we could do it. It was through ingenuity, insight, leadership and sheer perseverance that the team was able to overcome these difficult technological challenges."

NASA recently gave the go-ahead for the second stage of development for the mission, which will not only be able to search for Earth-like planets around other stars, but will also measure cosmic distances several hundred times more accurately than currently possible. Scheduled to launch in 2009, it will scan the heavens for five years and provide astronomers with the first truly accurate road map of our Milky Way galaxy.

"This is a historical time that we're intimately involved with," Watterson said. "Unlike any other culture in history, we have the technological means, the budget, and the will to determine the occurrence of Earth-like planets orbiting other stars. Everyone on the team is aware of their role in this pivotal stage in the search for life elsewhere in the universe."

The Space Interferometry Mission is managed by JPL as part of NASA's Origins program.

Written by Randal Jackson/Planet Quest
Jet Propulsion Laboratory, Pasadena, Calif.



2003-Jul-23, 08:14 PM
Originally posted by kashi@Jul 23 2003, 09:31 AM
True true "Magenta". It's also interesting that the detection of planets didn't get any mainstream media attention until Marcy and Butler at San Francisco University found the 2nd and 3rd planet (around a main sequence star), after which they appeared on the cover of Time. I'd love to get a copy of that issue...I wonder how I would go about tracking it down.

Actually, the discovery of 51 Pegasi's planet got lots of publicity. For example, Nightline did a whole show on it (on October 19, 1995), well before any new planets were discovered. Unfortunately, the discoverers--Mayor and Queloz--were not allowed to talk about their discovery, thanks to Nature.

2003-Jul-24, 06:52 PM
Extra-solar planets is indeed the coolest thing going on.

I was awakened to it about 4 years ago when the 20 some-odd known at the time were featured in Discover Magazine which I saw in a Dr.s office.
I photo-copied the three pages depicting the planets which I still have, somewhere.

I keep hoping we find planets around the very closest stars, such as Alpha Centauri, or Barnard's Star.

2003-Jul-28, 07:19 AM
Not likely we'll discover one around alpha centauri as it is - to my knowledge - a binary system.

Magenta you can't deny that Marcey and Butler discoveries got far more publicity than Mayor and Queloz's. They were on the cover of Time!!!


2003-Aug-11, 12:17 AM
A bianary system doesn't prevent planets from being there, unless the planets orbit crossed the path too near one or the other.

In fact I think I recall Universe Today carrying the story of the first planet orbiting two stars. I believe it was 2000 or early in 2001.

However, I do concede it's not likely that planets will be found near Alpha Centauri A, or B because of how close those stars are to each other, and that they orbit each other.

But star C usually called Proxima Centauri because it is the closer to us of the three may have a small planet or even asteroids around it, because it is quite a ways from the other two stars. But life is out of the question, and especially since it's not considered to be a mainstream star.

There has been speculation in the past of planets associated with Barnard's Star and Lalande which are the 2nd and 4th closest star systems to us. But there's no proof. Especially considering both are red dwarf stars and can be purturbed by nearly anything down to the size of our Moon.
Sirius is known to have a white dwarf conpanion, and planets isn't out of the question, although life possiblilities are.

More recently a new star was discovered out past Alpha Centauri which may become the new 4th closest star system to us. Any planets possiblilties are too early to consider, but not impossible.

But my point was it would be nice to find planets with stars that close.
Because if we can develop space ships that can go as little as 1/10 of light speed
we can make it to such places within a single human life span.
Otherwise ever visiting an exo-planet will remain impossible until we can achieve at least 25% of the speed of light as the closet star known to have planets is Epsolion Eri. nearly 11 light years away.

We can still hope.

2003-Aug-12, 02:12 AM
Thought I would add this link as well:


Thats 107 for those counting, ranging in size from the earth mass planets around the neutron star to the upper reaches of planets.

Considering the very short time that people have had to measure the radial velocities of various stars, I figure this number will double very quickly.

2003-Aug-12, 12:33 PM
i say they are 116, and that's indisputable: B)
Planet Quest (http://planetquest.jpl.nasa.gov/)

2003-Aug-12, 06:38 PM
Last I knew there were 115. Most Wanted may well be right with 116.

It's getting harder to keep up as new discoveries come all the time now.

Any rate I checked out both links and added them to my list of exo-planet sites.

Thanks guys.

2003-Aug-13, 05:53 PM
As of July 2003, the 110 planets are known outside our solar system.

Here's the site (http://exoplanets.org/) that I got this from.

2003-Aug-13, 06:04 PM
Fraiser and Most Wanted, you both supplied links to the same site.
The link doe's say 110.

Manchurian Taikonaut
2006-Jun-12, 04:11 PM
Astronomers have found disks of dust and gas, the raw material for planet making, around objects that are only a few times heftier than Jupiter. These findings suggest that miniature versions of the solar system may circle.


Three years of scouring the skies with a "homemade" telescope fashioned from commercially available parts has finally paid off for astronomer Peter McCullough.
First came the observation of the brief but telltale dimming of a sun-like star 600 light-years away, then the detection of the star's wobble indicative of an orbiting planet's presence.
Finally, McCullough's international team of professional and amateur astronomers received the official word that they had discovered a Jupiter-sized planet.


Extrasolar Planets Encyclopaedia - Star : XO-1

2006-Sep-17, 02:36 PM
A new online magazine, dedicated mostly to the field of extrasolar planets:


Jovan [XSM]

2006-Oct-16, 05:44 PM
XSM #3 is now online



2006-Oct-17, 08:48 PM
Added the index.