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chornedsnorkack
2018-Nov-15, 04:24 PM
Well, what is it?
What is the difference between a super-Earth and a mini-Uranus?
There is an observed low frequency of planets with diametre between 1,5 and 2x Earth.
Equally, that´s not a full absence.
And the statistic is based on planets of known diametre.

Planets for which both diametre and mass are known are a small fraction of planets for which diametre is known.

Furthermore, the already small sample is biased to planets with short period - mostly high insolation.

Uranus has diametre 4,0x Earth, mass 14,5x Earth, and insolation at 19,2 AU.

Barnard b has diametre unknowable, mass >3,2 Earth, and insolation equivalent to 6,9 AU.

Is there any evidence that Barnard b is a super-Earth rather than a mini-Uranus?

Jean Tate
2018-Nov-15, 05:23 PM
In the eye of the university PR department which creates PRs using the term?


Is there any evidence that Barnard b is a super-Earth rather than a mini-Uranus?

Not that I know of.

Noclevername
2018-Nov-15, 05:38 PM
AFAIK neither is an "officially" defined term.

Roger E. Moore
2018-Nov-15, 05:41 PM
I've seen a number of different interpretations of "super-Earth" and "mini-Neptune" and "ice dwarf" and what all, and they all describe about the same thing.

Spacedude
2018-Nov-15, 07:25 PM
I had assumed that a "super earth" was more of a rocky body rather than being a gas giant. But since we cannot actually see the planet it's just guess work.

Roger E. Moore
2018-Nov-15, 08:21 PM
It is guesswork and difficult to pin down. Here are some 2018-discovered super-Earths and their sizes. The third paper says it best.

https://arxiv.org/abs/1809.05967
TESS Discovery of a Transiting Super-Earth in the π Mensae System
2.04 ± 0.05 R⊕ and 4.82 ± 0.85 M⊕

https://arxiv.org/abs/1808.00485
A second planet with an Earth-like composition orbiting the nearby M dwarf LHS 1140
1.727 ± 0.032 R⊕ and 6.98 ± 0.98 M⊕

https://arxiv.org/abs/1802.03090
Formation of Super-Earths
Super-Earths are the most abundant planets known to date and are characterized by having sizes between that of Earth and Neptune, typical orbital periods of less than 100 days and gaseous envelopes that are often massive enough to significantly contribute to the planet's overall radius.

https://arxiv.org/abs/1805.04774
Super-Earth of 8 M-earth in a 2.2-day orbit around the K5V star K2-216
1.75 +0.17/-0.10 R⊕ and 7.4 ± 2.2 M⊕ minimum, up to 8.0 M⊕ or so

DaveC426913
2018-Nov-15, 11:49 PM
I had assumed that a "super earth" was more of a rocky body rather than being a gas giant. But since we cannot actually see the planet it's just guess work.

Yes. That's what I was about to point out.

There's surely a distinction between terrestrial bodies and gaseous bodies. The fact that we don't know which it is is a separate question.

Dave241
2018-Nov-24, 09:51 PM
I think another reason that "super earth" is used rather then "mini uranus" is that only one of those sounds like you are saying "tiny backside". :D

ktevolved365123
2019-Mar-04, 06:05 PM
A planet that is terrestrial and rocky like Earth.