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

Posted by timothy on from the one-in-a-million-no-wait dept.

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.

8 of 90 comments (clear)

  1. We can only detect planets they pass their star by BenJeremy · · Score: 4, Interesting

    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.

    1. Re:We can only detect planets they pass their star by wonkey_monkey · · Score: 3, Interesting

      We can only detect planets they pass their star

      Wrong.

      --
      systemd is Roko's Basilisk.
    2. Re:We can only detect planets they pass their star by Eloking · · Score: 3, Informative

      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?

      --
      Elok
    3. Re:We can only detect planets they pass their star by wonkey_monkey · · Score: 3, Interesting

      Furthermore:

      https://en.wikipedia.org/wiki/...

      So they are expecting to be able to detect planets via "perpendicular" observation (and may have already done so, but it's not been fully confirmed).

      --
      systemd is Roko's Basilisk.
  2. Too soon by Kjella · · Score: 4, Interesting

    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.

    --
    Live today, because you never know what tomorrow brings
    1. Re:Too soon by CanadianMacFan · · Score: 3, Informative

      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.

  3. For sufficiently small values of 'rare' by Anonymous Coward · · Score: 4, Interesting

    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.

  4. Re:Young Man Given Undue Credit; news at 11 by gordo3000 · · Score: 3, Insightful

    or maybe he actually did the grunt work of digging through the data and running the numbers?

    who knows, but lots of undergrads and even grad students get their first publication by basically doing really pedestrian grunt work for fully independent scientists. Even famous scientists usually start out that way. Why should it be any different for this kid?