HD 10180—a sunlike star in the southern constellation Hydrus—may have as many as nine orbiting planets.And concludes with the following quote from the study leader:
"So [our] solar system is only one example among a spectrum of different planetary systems we will find in the near future and [is] definitely not unique."Let us ponder this.
-- study leader Mikko Tuomi, astronomer at the University of Hertfordshire
What is HD 10180 system like? The star lies about 127 ly distant and cannot be seen north of the tropics. It is a G1-V star, not unlike the Sun. Its mass is about 1.06S, its diameter 1.20S, and its luminosity 1.49S. Its elemental abundance (exc. H and He) is 1.20 times the Sun. Its estimated age is 7.3 bya, making it 60% older than the Sun. It is a stable star but with no significant magnetic activity. So: older, fatter, brighter, but not putting out.
There were five planets identified previously, two additionals confirmed by the reanalysis, and two new possibles also identified in the reanalysis. This makes a total of nine planets.
- HD 10180 b. Hot Super-Earth. Mass: 1.4 Earths. Distance: 0.02 AU (one-seventh the distance of Mercury, and from a hotter, bigger star). Orbit: 1.1 days.
- HD 10180 c. Hot Neptune. Mass: 13 Earths (comparable to Uranus), likely a gas giant. Distance: 0.06 AU (still closer than Mercury). Orbit: 5.7 days
- HD 10180 i. Possible Hot Super-Earth. Mass: 1.9 Earths. Distance: 0.09 AU (still closer than Mercury). Orbit: 9.6 days
- HD 10180 d. Hot Neptune. Mass: 11.9 Earths (somewhat smaller than Uranus), likely a gas giant. Distance: 0.13 AU (still closer than Mercury!). Orbit: 16 days.
- HD 10180 e. Hot Neptune. Mass: 25 Earths (ca. 1.5 Neptunes; 0.25 Saturn). Distance: 0.27 AU (just a little closer than Mercury). Orbit: 49.8 days.
- HD 10180 j. Possible Hot Super-Earth or gas dwarf. Mass: 5.1 Earths. Distance: 0.33 AU (about the distance of Mercury). Orbit: 68 days.
- HD 10180 f. Hot Neptune. Mass: 24 Earths (ca. 1.5 Neptunes; 0.25 Saturn). Distance: 0.49AU (beyond Mercury, but not near Venus). Orbit: 122 days.
"tight and wild orbit is analogous to that of Mercury, with a similar black body temperature range, though with its immense mass, any greenhouse effect caused by an atmosphere would give it searing Venus like or greater temperatures."
- HD 10180 g. Gas giant. Mass: 21.4 Earths (ca. 1.25 Neptunes). Distance: 1.4 AU (Just short of Mars). Orbit: 596 days.
"fully within the system's predicted habitable zone, though it does not fit the current models for planet habitability. Due to its large mass, it is likely to be a Sudarsky Class II gas giant. there is a possibility that a natural satellite with sufficient atmospheric pressure could have liquid water on its surface."
- HD 10180 h. Saturn-size Gas Giant. The largest and outermost known planet in the sytem. Mass: 65 Earths (2/3rd Saturn). Distance: 3.4 AU (comparable to outer part of asteroid belt).
So what are we to make of Prof. Tuomi's assertion that this shows that "[our] solar system ... [is] definitely not unique." A fine example of the Copernican Syndrome. He can only mean that it is not unique in being a solar system; but it certainly seems so far that it is unique in terms of its make up. That is, it does not differ in matter, but surely does in form. And as we all know, it is form that imparts powers to matter.
There have been 763 extrasolar planets discovered in 611 solar systems, 101 of which contain multiple planets. Can anyone think of any manner in which our solar system remains unique among them?