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.