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Looking For Jupiter-Class Planets Indicates Solar Systems Like Ours Are Rare (theconversation.com) 90

An anonymous reader writes: A high school senior from New York analyzed data for more than 1,100 stars and pinpointed the frequency of Jupiter analogs (planets with similar mass and orbital period to Jupiter) to 3%. He published his results in a paper for the Astrophysical Journal. The relative rarity of Jupiter-like planets indicates that true solar system analogs should themselves be rare. By extension, given the important role that Jupiter played at all stages of the formation of the solar system, Earth-like habitable planets with similar formation history to our solar system will be rare.
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Looking For Jupiter-Class Planets Indicates Solar Systems Like Ours Are Rare

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  • by Anonymous Coward

    From the article:

    In a recent paper, Dominick Rowan, a high school senior from New York, and his coauthors (including astronomers from the University of Texas, the University of California at Santa Cruz and [me, a postdoctoral fellow at the University of Texas)...

    Look, it's great that this kid is involved, but quit lying about his contribution; when surrounded by such co-authors, even a monkey could have participated successfully.

  • Very rare indeed (Score:1, Informative)

    by Kethinov ( 636034 )

    "Solar systems" like ours are rare indeed, because there is only one Solar System.

    It's a proper noun.

    The term the article was looking for was planetary system.

    • I'm also wondering if there are solar systems (or whatever the proper name is) that aren't rare.
      Is there some standard kind of solar system that is very common?

      • LOL .. scary, dangerous, and hostile to life. :-P

        But, really, think about it ... even at 3% that's a crap pile of solar systems in our galaxy alone.

        I mean, even 3% of "beyond really grasping", is still "beyond really grasping".

        To quote Armageddon ...Begging your pardon, sir, but it's a big ass sky.

      • It seems so. The common kind have large planets (or companion brown dwarves possibly) very close in to the star, often in quite elliptical orbits.

    • There is a moon that orbits the Earth that English speakers normally just call "the Moon" (note the capital letter for a proper noun). That doesn't mean there aren't other moons (obviously). If we need to give it a name, I'd suggest the Latin name (Luna), but most people don't use that terminology. Similarly, we are in "the Solar System", but I don't see a problem calling other systems "solar systems"; they just aren't THE solar system.
      • That's a popular colloquial usage, but the astronomy community doesn't (yet?) accept "solar system" as a generic term like it does with "moon."

        For the time being, the correct term is planetary system. Usage of "solar system" as a generic term is wrong.

        • I don't think that the astronomy community cares enough to have come to a settled decision on the question.
      • The moon is called Luna when we want to be really clear which moon we're talking about. It's just that in most contexts nobody would mean any moon other than the nearby visible one.

        • by Teancum ( 67324 )

          The Moon is called Luna by a bunch of science fiction authors and a bunch of folks who for some reason choose not to communicate in English when they are otherwise communicating in English. The proper term when using the English language is simply "The Moon".

          Selene and that big hunk of cheese in the sky are somewhat acceptable alternatives, but you can take that for a grain of salt. A great many cultures each have their own term which is used for that fairly large (from an apparent viewpoint of somebody o

  • by BenJeremy ( 181303 ) on Saturday December 12, 2015 @06:00PM (#51107025)

    It's rather premature to declare all those systems devoid of planets when our primary means for detecting possible planets is when they pass between our planet and their star at the same time we observe them. Jupiter takes 12 years to make an orbit. As a simple logic problem, that means that we have to one opportunity to observe Jupiter passing between Sol and some sort of earth-analog in another system.... and that makes the HUGE assumption that that earth-analog is aligned with the solar system's orbital plane. If the earth analog happens to be staring down north-south on Sol, it isn't going to detect any planets.

    There are a few other ways to detect planets, but those are special cases, again, very rare, and detecting very unique planets.

    Detecting Sol-like systems is still extremely difficult.

    • We are living in a 3D world, not in a 2D world.
      An observed planet does not need to be in the plane of our solar system. It does not matter if the observed planet cuts over its sun from left to right ... our plane ... or from top to bottom. However you are right, the ways how a extra solar system my be 'turned' toward us so we can see it with current techniques is quite restricted.

      • We are living in a 3D world, not in a 2D world.
        An observed planet does not need to be in the plane of our solar system. It does not matter if the observed planet cuts over its sun from left to right ... our plane ... or from top to bottom. .

        I think he meant if we are looking at the "north pole" of the other star, then any planets moving around it will not pass between it and us.

    • by wonkey_monkey ( 2592601 ) on Saturday December 12, 2015 @06:52PM (#51107229) Homepage

      We can only detect planets they pass their star

      Wrong [wikipedia.org].

      • Well, you've exchanged edge-on for perpendicular as a limitation.

        Congrats.... you've exactly doubled the potential cases for detection, which is still a small percentage of the systems we can observe.

        • Your parent was wrong and you missunderstood the animation on the wiki.
          Perpendicular dors not make a doppler effect.
          Only a sun that drifts away from us and then comes back toward us produces a doppler effect.
          Hence the planet still needs more or less cross the sun from our point of view. (the planet my near miss though, in this case)

      • Actually: not wrong.
        To use the doppler method to find a distant planet, the planet still needs to cross its sun or needs to be in a very close range of degrees above or below (besides on side or the other) of that sun. So the limitation to find it is more or less the same as crossing the sun.
        Hint: the animation on the wiki page is missleading. There is no doppler effect if you look on a planets orbit from 'atop'.

    • by Eloking ( 877834 ) on Saturday December 12, 2015 @06:53PM (#51107233)

      It's rather premature to declare all those systems devoid of planets when our primary means for detecting possible planets is when they pass between our planet and their star at the same time we observe them. Jupiter takes 12 years to make an orbit. As a simple logic problem, that means that we have to one opportunity to observe Jupiter passing between Sol and some sort of earth-analog in another system.... and that makes the HUGE assumption that that earth-analog is aligned with the solar system's orbital plane. If the earth analog happens to be staring down north-south on Sol, it isn't going to detect any planets.

      There are a few other ways to detect planets, but those are special cases, again, very rare, and detecting very unique planets.

      Detecting Sol-like systems is still extremely difficult.

      Well unless the scientist working on this are total moron, you can quite easily do some statistic analysis to guess the number of Jupiter-like planet in other planetary system even with those complication . Here's a quick example. Let's suppose the world is in 2D and make every orbit are perfectly round to simplify things. A planet have a 360 orbit and let's say we can only see the planet for 0.01 (so 1/36000) of their orbit with 100% accuracy. So if you scan 72000 star and find 4 planets, you can then make the assumption that there's 2 gas planet per planetary system on average.

      Am I missing something?

      • by trenien ( 974611 )
        I would say there is a problem with the size of the sample (it does need to be above a threshold to draw valid conclusions).

        Right now, the number of systems we've detected is somewhat above a thousand. There are around 100 billions stars in our galaxy alone. So, in other words, the people who wrote that article have decided that a 0.000001% sample is enough to draw conclusions.

        On top of that, what a surprise, said conclusion is that the Solar System is a (very?) rare occurrence. I haven't taken the time

    • About the orbital plane of the other planetary systems: yes, it's a very low probability that any given star would have its planets' orbital planes appropriately aligned. However, the math is simple, allowing one to extrapolate from the small number of Solar-system like planetary systems that happen to be aligned, to the overall population of Solar system-like planetary systems. And one can also calculate the % of stars whose planetary orbits ought to be aligned vs. the number of systems we observe, to gi
      • by trenien ( 974611 )
        The maths might simple, but that doesn't mean they're valid if the data sample is too small.
        • I'm not sure which data sample you're referring to, but the math doesn't rely on the kind of data sample you'd get from observations of planets orbiting stars; it just requires knowing the size of a star's disk from the perspective of a hypothetical planet orbiting that star at a hypothetical distance. We know from other observations what the diameter of various kinds of stars is, so we can calculate the rest.
          • by trenien ( 974611 )
            That's exactly what I'm saying: you're relying a lot on mathematical projections with the kind of reasoning you describe. However, you need hard data to make valid assumption, and enough of it. I haven't read the actual scientific article, but the one reporting on it makes it quite clear that the conclusions they've arrived at were based on the observation of actual planetary systems: i.e. an extremely small sample to draw conclusions from.

            Maths are a tool to be used in astronomy. When you get to the poin

      • What's the distribution of the stars' ecliptics relative to the galactic equivalent? I know ours is tilted, or the milky way would be round the equator, which it isn't. And I looked it up.

        Presumably we can deduce it for those where we can detect expolanets by, say, doppler shifts. But isn't there a selection bias there?

        • by osu-neko ( 2604 )
          We can confirm the ecliptics for billions of star systems; no exoplanets are required, given that the majority of stars are part of multiple star systems. And there's no reason to think that some bizarre unknown force causes systems with only one luminous member to align their ecliptics in a way that systems with multiple luminous members don't.
          • At first I doubted whether the alignment of binary stars' orbits had anything to do with the alignment of planetary systems. Planetary systems condense out of disks that form as individual stars collapse out of gas and begin to spin up. So the disks--and the eventual planetary systems--are presumably aligned with the equator of the spinning stars. But binary stars, I would have thought, arise from gravitational capture in multi-star systems. But in fact my guess was wrong: https://en.wikipedia.org/wiki/ [wikipedia.org]
          • And there's no reason to think that some bizarre unknown force causes systems with only one luminous member to align their ecliptics in a way that systems with multiple luminous members don't.

            Where did I suggest there was, you pompous cunt?

            If you can't give a civil reply to a question then FUCK OFF.

        • I know ours is tilted, or the milky way would be round the equator, which it isn't. And I looked it up.

          I read that as "and I looked up" which would also work.

  • Too soon (Score:5, Interesting)

    by Kjella ( 173770 ) on Saturday December 12, 2015 @06:03PM (#51107045) Homepage

    Jupiter has an orbital period of 12 years. From what I've understood it takes 3 passes to confirm an exoplanet, meaning 0-12 years to initial discovery + 2*12 = 24 years for a Jupiter-class planet. It's only been 23 years since the first exoplanet was discovered in 1992 and detection capability has improved much since then, so it's way too early to tell. Maybe you can start making semi-educated guesses from lack of candidates, but that too seems premature. In another 15-20 years, we'll have much better answers.

    • Re:Too soon (Score:4, Informative)

      by CanadianMacFan ( 1900244 ) on Saturday December 12, 2015 @06:43PM (#51107185)

      That's if you are using the difference in light to detect the planets but there are other ways. If you use the wobble of the star caused by the pull of the gravity by the planet you don't have to wait for three rotations of the planet. It also allows you to examine star systems that have an orbital plane shared with Earth. If we look "down" on the system we would never see a planet move in front of the star but we would see the star move.

      • The farther out the planet is, the longer the orbital period is and the slower the wobble. I don't know how much of a factor that is, but I do know that most of the exo-planets I've read about are close in with short orbital periods.
  • by Anonymous Coward

    In what way can an analysis of 1,122 stars be considered significant?
    How were these 1,122 selected? The paper is almost deliberately vague on this point, simply choosing to refer to them as "our sample".
    The phrase, "A high school senior from New York analyzed data" is highly misleading. There were 13 authors.
    The paper only takes data from one telescope. Presumably this paper was not the telescope's primary focus (if it was someone needs to pull the funding now) so the data has been collected as a side pr

    • by Teancum ( 67324 )

      How were these 1,122 selected? The paper is almost deliberately vague on this point, simply choosing to refer to them as "our sample".

      It isn't that big of a deal if you are considering the database of stars that have been found with the Kepler Space Telescope [nasa.gov], which is by far the largest source of information about exoplanets available at the moment. You say it was data taken from just one telescope, but the science is about as sound as it gets.

      Most of your questions can be answered by simply removing your ignorance about this particular instrument, which is 100% dedicated to just analysis of exoplanets and gathering data about them. Wh

  • by Anonymous Coward on Saturday December 12, 2015 @06:42PM (#51107181)

    At roughly 3%, that means about 100x as many Jupiter analogs in our galaxy as there is carbon dioxide in our atmosphere (by percentage).

    At roughly 3%, that means there are only about 10 billion Jupiter analogs in our own galaxy of roughly 300 billion stars.

    Yes, 'rare' is a relative word especially when you are dealing with numbers that seem to be beyond human comprehension.

    • by Bob_Who ( 926234 )

      At roughly 3%, that means there are only about 10 billion Jupiter analogs in our own galaxy of roughly 300 billion stars.

      Yes, 'rare' is a relative word especially when you are dealing with numbers that seem to be beyond human comprehension.

      Exactly...er....um...... relatively speaking.

      This is why we need to develop Star Fleet and mine di-lithium crystals and platinum group metals from asteroids.

      Its seems like a better idea then burning jet fuel and bombs for political reasons that won't matter in the absense of matter.

  • then you'll likely get a 1% result. Divide the pie up and you get lot of pieces, funnily. There's probably a name for it too.

  • The lack of jupiter orbit type gas giants in the sample does not mean a dirth of possibly habitable candidate objects.

    Like always, they completely ignore the prospect of large numbers of moons around extra solar gas giants, and thus ignore the prospects of possibly habitable moons.

    Granted, there isnt sufficient data to make even rough estimates of that yet, since we cant really "direct image" extra solar planets to look for moons, but that is likely to change when James Webb launches and starts performing s

    • by osu-neko ( 2604 )

      Almost as disturbing as their failure to acknowledge that there may be dozens of species of jumping spider that are currently unknown! Indeed, these are just two of the many things that might be true that they fail to acknowledge in their paper on a particular study that wasn't studying those things....

  • Based on the plot, it looks like the type of planet/orbit detected is closely tied to the detection method. That implies we are not getting a full sample of actual planets.

  • This is why you don't leave important scientific "facts" to high schoolers to "discover"

    Cool, the kid analyzed some existing data, but what about the truth to said data? How do we know the transit period of a planet around a star? We measure the dimming light of the star on a periodic basis. After three transits, we can determine with an amount of certainty that it is indeed a planet, and not just other objects obscuring the star.

    Jupiter transits Sun aprox every 12 years. This would mean at a bare minimum o

  • The reason we find so many gas giants close to stars is because those are easy to find. Jupiter-like planets are much harder to find, and hence underrepresented in the data. You can use the data as a lower bound, but not as an upper bound.

  • There aren't any others.
  • I was under the impression that one planet 8x the size of earth orbits close to a dim star was in a zone where water would be a liquid and hope for life, yet Wikipedia claims otherwise.
    https://en.wikipedia.org/wiki/... [wikipedia.org] (it being likely to have a runaway greenhouse effect).

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