HD 10180 – Densely-Packed Planets

Some more exoplanet news. There’s a paper out describing a system with a rather-startling minimum of five (and maybe seven) planets. These are all Neptune-analogues, in mass terms, and they’re packed in between 0.06 to 1.4 AU. So that’s a lot of planets in a pretty small space – transpose them into our solar system, and they’d all orbit inside of Mars.

20 years ago, no-one would have believed that an arrangement of planets like that could even *exist*, let alone be stable.

Also, something else caught my eye. Looking at the numbers for the star – luminosity, metallicity, age – it really does look very solar. No surprise, I suppose, as the spectral type is G1 against G2 for our Sun. Also, planet g, with a suggested orbit of 1.4 AU. That’s presumably still inside the star’s biozone. So if it had any decent-sized moons, the possibility of an interesting climate can’t be entirely ruled out.

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2 Responses to “HD 10180 – Densely-Packed Planets”

  1. Wow O_O I’m increasingly of the opinion that the solar system is rather dull and conservative compared to what’s out there. I’m just trying to imagine what the night skys would be like in this system, pretty busy I think.

    If there was a moon in the habitable zone, with all these large bodies comparatively close I bet it would experience some interesting tides.

    • Actually, the odd thing is, compared to the others, ours is the weirdo, rather than the boring one! Most exoplanet systems discovered so far feature either single hot Juipters in handful-of-days orbits, or are practically double-parked with planets, like the above one. Systems like our own, by contrast, seem to be rather rare. And it does raise the question of why.

      Of course, some of this may be premature. For various technical reasons, it’s a lot easier to find big planets in close orbits rather than smaller ones much further out, so current searches certainly are biased against ‘cold’ Jupiters or Saturns.

      However, that said, there is still a statistically-significant population of hot Jupiters out there.

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