Extra solar planets

[anigma46]

Since a lot of the newly discovered gas giants are near their stars,could our planet Mercury once been similar. The atmosphere could have been evaporated,or blown off by the solar winds over millions of years. If gas was blown off along the ecliptic it could have been captured by Venus earth or mars eventually. Nah probably not!!!

 

[nexium]

Your hypothesis seams as reasonable to me as most of the other ideas of how our solar system got the way it is. I don't know the math. If Jupiter was in a circular orbit, ten million kilometers from our present sun, would it loose 1% of it's hydrogen per million years? If so, the loss of volitiles would be greater after 100 million years as nearly all the hydrogen would be gone. Venus and Earth with more mass of non-volitiles would sweep up volitiles with high molecular weight faster than they would lose them. Neil

 

[newtonian]

nexium - Yes, many theories.<br /><br />However, the molecular weight of the various gases is an important factor.<br /><br />Hydrogen is much more likely to escape than carbon dioxide, for example.<br />You all:<br /><br />Which is your favorite theory for solar system origin, including planets and other solar systems?<br /><br />For me, I consider our solar system to be fine tuned for life on earth.<br />

 

[alokmohan]

NASA Telescope Finds Planets Thrive Around Stellar Twins <br /><br />PRESS RELEASE<br />Date Released: Wednesday, March 28, 2007<br />Source: Jet Propulsion Laboratory<br /><br /><br /> <br /><br /> <br /><br />The double sunset that Luke Skywalker gazed upon in the film "Star Wars" might not be a fantasy. <br /><br />Astronomers using NASA's Spitzer Space Telescope have observed that planetary systems – dusty disks of asteroids, comets and possibly planets – are at least as abundant in twin-star systems as they are in those, like our own, with only one star. Since more than half of all stars are twins, or binaries, the finding suggests the universe is packed with planets that have two suns. Sunsets on some of those worlds would resemble the ones on Luke Skywalker's planet, Tatooine, where two fiery balls dip below the horizon one by one. <br /><br />"There appears to be no bias against having planetary system formation in binary systems," said David Trilling of the University of Arizona, Tucson, lead author of a new paper about the research appearing in the April 1 issue of the Astrophysical Journal. "There could be countless planets out there with two or more suns." <br /><br />Previously, astronomers knew that planets could form in exceptionally wide binary systems, in which stars are 1,000 times farther apart than the distance between Earth and the sun, or 1,000 astronomical units. Of the approximately 200 planets discovered so far outside our solar system, about 50 orbit one member of a wide stellar duo. <br /><br />The new Spitzer study focuses on binary stars that are a bit more snug, with separation distances between zero and 500 astronomical units. Until now, not much was known about whether the close proximity of stars like these might affect the growth of planets. Standard planet-hunting techniques generally don't work well with these stars, but, in 2005, a NASA-funded astronomer found evidence for a planet candidate in one such multiple-star system (http://www.jpl.nasa.go

 

[qso1]

Thats good news for me since I've been writing a book this past year, a book I originally wrote in 1982...about the first intestellar mission. In the original, I made up a double star system with an Earthlike planet. The newer version I simply used Alpha Centauri. I like the idea of using a real star system.<br /><br />Alpha Centauri is a triple system of course, but Proxima is so far away from the main components that it would look like another star, and a dim one at that, from a planet orbiting at 1 AU from Alpha "A" or "B". <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[3488]

Hi alokmohan & qso1.<br /><br />This is fascinating news. Thanks for sharing it alokmohan.<br /><br />I remember not so long ago that the idea of planets forming around binary or multiple stars being ruled out, due to unstable tidal influences on the protoplanetary disk. <br /><br />Planetary formation appears to be a hardy process. Perhaps the search ought to be carried out around stars like Sirius, Procyon, Alpha Centauri, etc. I wonder, the sunlike star with the red dwarf companion Eta Cassiopiea??? <br /><br />Please see these links:<br /><br />Binary Sunset.<br /><br />Binary Protoplanetary disks.<br /><br />Binary solar system movie.<br /><br />Hope you find the above interesting.<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[qso1]

Hi 3488.<br /><br />At the time I was writing my book, I had a book written by respected and world reknowned astronomer Patrick Moore who virtually ruled out the possibility of planets around other stars in part for the reasons you stated. Instability but I think he was making a case for instability because the planets would presumably be affected by both stars.<br /><br />Of course, I'm not the first to propose the idea that planets can orbit close binaries. I'm not even an expert. But I bring it up because I wanted as much astronomical reality in the story as possible and I simply scaled the Alpha Centauri "A" and "B" systems on paper and seeing that "B" is roughly comparable to Saturns distance at close approach...I had my answer. I did factor in the more massive size of the "B" star and worked up an elliptical orbit for the planet in question.<br /><br />I do agree that a planet in a binary system consisting of close stars would have a tough time and this is illustrated in my book, earthlike worlds especially. Whereas an earthlike planet orbiting Zeta Reticuli "A" would hardly be affected by ZR "B" because that system is spaced so much further apart.<br /><br />I agree with you, widen the search to Sirius, Procyon, etc. After all, the first extrasolar worlds were found in orbit around a kind of star no serious astronomer thought could have planets...Pulsars.<br /><br />Great links BTW, thanks. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[3488]

Hi qso1, you can call me Andrew.<br /><br />Yes I was aware of that & confirms how robust the planetary formation process is.<br /><br />PSR B1257+12 in the constellation of Virgo the Virgin.<br /><br />Now it is thought that planets can even form around super powerful blue supergiants like, Deneb, Rigel, Alnilam, Alnitak, Saiph & even hypergiants like Rho Cassiopiea!!!<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[MeteorWayne]

I wonder if there's an Altair 4 <img src="/images/icons/wink.gif" /> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[summoner]

How bout a VV Cephei? That'd be interesting orbiting a star nearly 2000 times larger than our sun.<br /><br />Linl <div class="Discussion_UserSignature"> <p> </p><p> </p><p> </p><p> <br /><table cellpadding="0" cellspacing="0" style="width:271px;background-color:#FFF;border:1pxsolid#999"><tr><td colspan="2"><div style="height:35px"><img src="http://banners.wunderground.com/weathersticker/htmlSticker1/language/www/US/MT/Three_Forks.gif" alt="" height="35" width="271" style="border:0px" /></div>

 

[doubletruncation]

<font color="yellow">I agree with you, widen the search to Sirius</font><br /><br />Looking for planets around Sirius is a very difficult thing to do for practical reasons. Stars hotter than F are essentially an unexplored territory for extra-solar planets, not because people don't think they exist but because it's a very difficult thing to do either with transits or with radial velocity surveys. For transit surveys the problem is that the hotter stars have larger radii which makes transits by planet sized objects shallower and hence more difficult to detect. The problem for radial velocity searches is that hot stars have nearly featureless optical spectra. Super-high precision radial velocity measurements for planet detection (down to m/s) make use of many absorption lines in the spectra to effectively beat down the error with which you can detect the shift in the spectrum. For F,G and K stars there are a plethora of absorption lines in the optical due largely to iron. For hotter stars you only have a few absorption lines so that your radial velocity measurement is limited by the precision with which you can centroid a single line - so for those stars you can't make measurements that are more precise than ~100 m/s or so. <div class="Discussion_UserSignature"> </div>

 

[vandivx]

<font color="yellow"><br />Planetary formation appears to be a hardy process. </font><br /><br />that's as may be but life is not hardy as witness the solar system where only one planet ever got a significant life developped on it (and even using the word 'significant' seems to be way overgenerous)<br /><br />vanDivX <div class="Discussion_UserSignature"> </div>

 

[summoner]

<font color="yellow">as witness the solar system where only one planet ever got a significant life developped </font><br /><br />That being said, we have no idea what the other solar systems look like. It could be that we are the exception and not the rule. <div class="Discussion_UserSignature"> <p> </p><p> </p><p> </p><p> <br /><table cellpadding="0" cellspacing="0" style="width:271px;background-color:#FFF;border:1pxsolid#999"><tr><td colspan="2"><div style="height:35px"><img src="http://banners.wunderground.com/weathersticker/htmlSticker1/language/www/US/MT/Three_Forks.gif" alt="" height="35" width="271" style="border:0px" /></div>

 

[vandivx]

lets hope its exception in the positive sense (meaning life on couple or more planets out there)<br /><br />I would rather tend to think that it will go the other way, that many solar systems will have planets in awkward orbits making them unsuitable for life<br /><br />I think it quite possible we will find microbial life on Mars, fosil or live, and maybe even higher forms, like fosil Trilobites or better, it is still open although not for anything better, like Martians but then again even that is possibility although extremely remote<br /><br />vanDivX <div class="Discussion_UserSignature"> </div>

 

[alokmohan]

We want earthlike planets .whether they exist or not.

 

[qso1]

3488:<br />Now it is thought that planets can even form around super powerful blue supergiants like, Deneb, Rigel, Alnilam, Alnitak, Saiph & even hypergiants like Rho Cassiopiea!!!<br /><br />Me:<br />Hi Andrew, guess we won't really ever know till we can start examining these stars. As doubletruncation pointed out in his response, the technical issues astronomers face with current methods (Transit photometry and radial velocity). Its also theorized in the cases of giants stars that resulted from going supernova, that most of their planetary systems were vaporized during the stellar expansion. However, outer planets could remain I would think. Gas giants at Saturn distance could, over the duration of the stellar expansion phase, loose much of its gaseous atmosphere and any rocky core would be exposed, becoming a rocky planet in the process. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[qso1]

doubletruncation:<br />Looking for planets around Sirius is a very difficult thing to do for practical reasons.<br /><br />Me:<br />Excellent points. I should have emphasized "Widen the search as technology becomes available" to support the kind of searches we cannot currently undertake due to technological limitations. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[qso1]

alokmohan:<br />We want earthlike planets .whether they exist or not.<br /><br />Me:<br />This is true. In fact, we might find after hundreds of years that earthlike planets are rare. This would cause an even bigger dissapointment among the general public about space exploration during the years between hoping to find numerous earthlike worlds and actually discovering only one after say, five hundred years of searching. And one too far to be practical for interstellar travel for hundreds of more years.<br /><br />Its almost like the scenario I proposed for ETs. We may be alone in the Universe and if so, we can never prove it. Same with earth like worlds. There may be none but we will never know that for sure. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[3488]

We might even come face to face with Silicon based life. We do not know how Carbon based & Silicon based would react.<br /><br />The point about alien bacterial infections MUST be followed through. Almost certainly humans will have no immunity toward them, likewise the other way around!!!<br /><br />I know that this is only speculation as nothing yet has been detected.<br /><br />Earth like planets in terms of size & mass IMO are common, but in a suitable goldilocks orbit around its parent Sun, now that is another matter.<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[vandivx]

what is 'Earthlike'? <br /><br />and I think you meant to say 'whether life on them exists or not'<br /><br />because Earthlike is any planets with firm surface, with atmosphere of not undue pressure and temperature, there doesn't have be any sign of life on it to qualify the planet as Earthlike IMO<br /><br />I would say Mars is Earthlike but Venus is not as well as those gas giant planets like Saturn and Jupiter or cold Pluto or hot Mercury (probably I am quite wrong here and I let myself be convinced of another Earthlike definition)<br /><br />vanDivX <div class="Discussion_UserSignature"> </div>

 

[mithridates]

This definition is limited to surface conditions though - up in the atmosphere Venus has the most Earthlike environment we know of so far. <div class="Discussion_UserSignature"> <p>----- </p><p>http://mithridates.blogspot.com</p> </div>