 March 6, 2013 - 11:05pm | Via G+ Asteroids caught in the lagrangian points of jupiter and the sun from the veritable trove sajri.astronomy.cz/asteroidgroups/groups.htm  "Jupiter is no accident", to explain what I'm saying check out The Privileged Planet if you can find it. I found this: http://www.youtube.com/watch?v=BFaSBEXum5g Also, check out Expelled: No Intelligence Allowed by Ben Stein. |
 March 8, 2013 - 8:04pm | Interesting. It is a galactic debris magnet. In every age, in every place, the deeds of men remain the same. |
 March 9, 2013 - 4:21pm | so one wonders if a gas giant in the inner system would do? suck debris in or something else? No doubt the other possible variables have a major impact. I might not be a dralasite, vrusk or yazirian but I do play one in Star Frontiers! |
 March 9, 2013 - 5:11pm | As I understand it, gas giants can't exist much further in than Jupiter due to the speed required to keep them from falling into the sun, and the closer to the sun they get, their atmosphere burns off and with it their massive weight and size. View my profile for a list of articles I have written, am writing, will write. "It's yo' mama!" —Wicket W. Warrick, Star Wars Ep. VI: Return of the Jedi "That guy's wise." —Logray, Star Wars Ep.VI: Return of the Jedi Do You Wanna Date My Avatar? - Felicia Day (The Guild) |
March 10, 2013 - 2:35am | I half remembered reading this: http://www.nasa.gov/home/hqnews/2010/jul/HQ_10-167_Hubble_Finds_Planet.html about a gas giant closer in than expected, its a cometary planet in that the atmosphere is being "burned off" (not sure if that the proper discriptor) and the solar wind forms it into a comet like tail behind the planet. At anyrate you are right, Ascent, the star does eventually destroy the planet but it seems they are possible a bit closer in. However, its probably more likely that this is a rogue planet picked up by that star. I might not be a dralasite, vrusk or yazirian but I do play one in Star Frontiers! |
 March 10, 2013 - 9:45am | Actually, most of the first extrasolar planets discovered were bigger than Jupiter and much (factors of 4-6) closer to their star than Mercury is to the sun. It was a selection effect due to the method of discover (big close planets were easier to find) but the numer is non-negligible. Even today, with nearly 600 known extrasolar planets most are Neptune size or bigger and closer to their star than Earth is to the Sun. So it is entirely possible and probable to have giant planets close to stars. Our current understanding of planetary formation says they can't form there and have to migrate in from further out and a lot of research is going on trying to understand exactly how these systems form. Given current statistics, our solar system is the odd ball. Ad Astra Per Ardua! My blog - Expanding Frontier Webmaster - The Star Frontiers Network & this site Founding Editor - The Frontier Explorer Magazine Managing Editor - The Star Frontiersman Magazine |
March 10, 2013 - 2:15pm | Either that, or there is an optical effect happening that makes large planets look closer to their sun than they really are and we haven't deciphered it yet. If the stars are actually further away than we think, (The distance of stars is always under dispute,) then perhaps that could have an effect on how a planet's distance from its sun is calculated. View my profile for a list of articles I have written, am writing, will write. "It's yo' mama!" —Wicket W. Warrick, Star Wars Ep. VI: Return of the Jedi "That guy's wise." —Logray, Star Wars Ep.VI: Return of the Jedi Do You Wanna Date My Avatar? - Felicia Day (The Guild) |
March 10, 2013 - 2:28pm | No, they really are that close. The detections are mostly based on doppler shift or transits. Very, very few are direct optical detections. The period of the effect measures the period of the orbit and it is sole determined by the mass of the star and the oribal distance. The amplitude of the effect is a function of the mass of the planet. It's pretty robust. Ad Astra Per Ardua! My blog - Expanding Frontier Webmaster - The Star Frontiers Network & this site Founding Editor - The Frontier Explorer Magazine Managing Editor - The Star Frontiersman Magazine |
March 10, 2013 - 6:30pm | Well, my second point was that if the star is further away from us than the popular belief, then the apparent distance of the planet to the star would be affected, as well as the size of the star, would it not? It seems to me that all it would take is a small change in the defined distance to produce a pronounced effect on the calculations. If further away, the star would be larger (and colder? Though the color, I think determines the size and temperature, correct?), the planet larger, and the distance between them more significant, resulting in the planet being in a less hostile atmosphere than determined with the current calculated distance of that star from our own. So let's say a star were 100 million miles further away from us than originally calculated. How would this affect the determination of the size of a star and its planet and the distance between them and the star's temperature? View my profile for a list of articles I have written, am writing, will write. "It's yo' mama!" —Wicket W. Warrick, Star Wars Ep. VI: Return of the Jedi "That guy's wise." —Logray, Star Wars Ep.VI: Return of the Jedi Do You Wanna Date My Avatar? - Felicia Day (The Guild) |
March 10, 2013 - 7:52pm | Very little if at all. Colors/tempuratures/masses are determined via spectroscopy and that is very insensitive to distance (other than if it is further away it is fainter and takes longer to get the spectra which is why they mainly do this for bright stars). There is some sensitivity to dust reddening the light but not much. That's why these methods are use, as they are pretty much free of those potenital errors. Now as with all measurements there are errors but they are well below the 10% level IIRC. And 100 million miles is only about the distance from the Earth to the Sun (93 million miles). Distance errors can be off by dozens of light years and not have any real impact on the calculations. You have to remember that we can resolve the disk (i.e. see it as more than just a point of light) of only a handful of stars: The sun, Betelguese, Antares, and a couple other farily close red supergiants (put Betelguese where the sun is and Jupiter would be inside the star, Antares is even bigger). So there is no "size" of the star to begin with. It's true that if our understanding of a given star was completely off base that would have an impact but with hundreds of stars now with known extrasolar planets, a single star wouldn't have much impact on the statistics. Ad Astra Per Ardua! My blog - Expanding Frontier Webmaster - The Star Frontiers Network & this site Founding Editor - The Frontier Explorer Magazine Managing Editor - The Star Frontiersman Magazine |
March 11, 2013 - 12:48am | Not to be a pain, but your the guy with the knowledge. Our understanding of most stars is based entirely on spectroscopy, is it not? Isn't that limited information? Could not a single undetermined (currently) factor be repeated so that we misjudge the distance, type and/or brightness among many stars? Would 100 AU's be too great a variable in such a circumstance? And would 100 AU's still be too little a variance to cause problems? If so, what distance variable of the star from us would be needed to change calculated distances of the rogue Jovians from their suns in order to fall in line with our understanding of when they lose their atmospheres? Are there any other scenarios you can think of where the distances for the rogue Jovians from their suns could be miscalculated based on limited or even faulty information? (I ask because so many theories, particularly regarding astronomy, tend to change, sometimes drastically.) View my profile for a list of articles I have written, am writing, will write. "It's yo' mama!" —Wicket W. Warrick, Star Wars Ep. VI: Return of the Jedi "That guy's wise." —Logray, Star Wars Ep.VI: Return of the Jedi Do You Wanna Date My Avatar? - Felicia Day (The Guild) |
March 11, 2013 - 3:53am | I'm trying to follow the back and forth here and figure out where Ascent is coming from? ...and I wonder if there is a little bit of "I dont buy these measurements and they must be off for some reason that we dont know yet" because possibly there is a little bit of young universe theory going on here? Large jovian planets to close to a star to have existed there for millions of years is actually a case for a young universe. I find the logic of "because its so close it must be a rogue" suspect anyways when it should be wow a jovian that close violates all our models we should study this more rather than write it off as it must be a rogue since it violates my preconceptions. I'm just trying to follow the conversation here and I suspect that I'm missing something? I might not be a dralasite, vrusk or yazirian but I do play one in Star Frontiers! |
March 11, 2013 - 12:49pm | No problems. 1) Our understanding of stars is based on data collected from spectroscopy and broadband observations all across the electromagnetic specturm plus fundamental physics (i.e. gravity, electromagnitism, mechanics, etc), nuclear physics, and chemistry. And we've been working on that for over a century. It's entirely possible there is an undetermined factor somewhere in there but it's unlikely. 2) Our best distances right now are probably only good to a few tens of AU to thousands of AU for the closest stars and get worse further out. There are 63239.7 AU per light year and accuracies are at 1 part per 10,000 on the closer objects and a part per 1000 or 100 or worse on the most distant ones. An error in distance is only an issue for the relatively few planets detected by direct imaging. And even there other errors greatly outweigh the errors from a slightly off distance measurement. Most detection are either purely geometrical in the case of transit detections (i.e. the planet passes in front of the star and block of a miniscule fraction of its light) or due to gravitational forces in the case of doppler shift detections (we see a wobble of the position of the spectral lines in the star as it moves toward and away from us due the mutual gravitational interaction. They are competely independent of the distance to the star from Earth. 3) These close in jovians are actually fairly stable. Their atmospheres are more extended ("puffed up") relative to objects further out (like Jupiter) because they are receiving much more solar energy but they are also massive and have a much higher gravitational pull on their atmospheres and so can hold on to atmopheres that are hotter as the escape velocity required for the atmosphere to escape is much higher. I haven't completely paid attention to the details of the research in this area but IIRC they can last for billions of years. And considering most of these are around stars similar to our sun that are only a few billion years old, they will still be around for a while. 4) I can't think of anything that would cause the distances to change. It's all based on very basic, fundamental, almost high school level physics. There is nothing really fancy going on. Errors are going to be small, on the 5-10% level at best and are typically due to timing resolution limits or detector sensitivies. Or in the case of the Kepler planets, we discovered that our Sun is actually really, really stable and quiet. The G type stars observed by Kepler have typically 3-5 times more "natural" variation in their energy output than the sun. This of course made the Kepler measurements much harder as there is more natural background noise to try to filter out to look for the really small signals. The bottom line is that we understand stars farily well and the basic physics being used for these planetary detections even better. There isn't much that can change the numbers and even then not by much. The reason it has only been in the last little while that detections have been made is insturment sensitivity. We are looking at variaions on the level of one part per 1000 to one part per million and the instruments and detectors have only been capable of that for the last couple of decades. And in the case of detecting a planet like Jupiter around our Sun, you have to observe the system for 1.5 orbital periods, i.e. 18 years, before you can confidently claim a detection. We just haven't been doing it long enough. Thsi is why most of the planetary detections are short periods (i.e. less than 1 year, usually less than a few months). You can detect them much faster and the signals you are looking for are much larger when the planet is closer to the star. Ad Astra Per Ardua! My blog - Expanding Frontier Webmaster - The Star Frontiers Network & this site Founding Editor - The Frontier Explorer Magazine Managing Editor - The Star Frontiersman Magazine |
March 11, 2013 - 4:46pm | Thanks. View my profile for a list of articles I have written, am writing, will write. "It's yo' mama!" —Wicket W. Warrick, Star Wars Ep. VI: Return of the Jedi "That guy's wise." —Logray, Star Wars Ep.VI: Return of the Jedi Do You Wanna Date My Avatar? - Felicia Day (The Guild) |
 March 11, 2013 - 4:50pm | Anyone seen comet Pan-STARRS yet? -iggy |
March 11, 2013 - 6:03pm | No. It was crystal clear here last night and I totally forgot. It's not looking so good tonight so I'll probably still have to wait. Ad Astra Per Ardua! My blog - Expanding Frontier Webmaster - The Star Frontiers Network & this site Founding Editor - The Frontier Explorer Magazine Managing Editor - The Star Frontiersman Magazine |
