Ratio of Earth-Sized exoplanets to other sizes of exoplanet?

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Discussion Overview

The discussion centers on the ratios of different types of exoplanets, specifically focusing on Earth-sized, Super-Earths, Ice-Giants, and Jovian planets. Participants explore the reliability of existing statistics regarding these ratios and seek additional resources or papers to further investigate the topic.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant references an article that claims the number of planets similar in size to Uranus and Neptune is nine times greater than that of larger planets like Jupiter and Saturn, expressing interest in exploring this further.
  • Another participant argues that such statistics are unreliable due to observational bias, noting that larger planets are easier to detect and suggesting that the actual ratio of Neptune-sized planets may be higher than reported.
  • A participant expresses intent to contact the author of the article for clarification on the source of the ratio mentioned.
  • Discussion includes the idea that planets do not fit neatly into categories, as exemplified by a specific planet that has gas planet densities but an Earth-like mass.
  • Several participants share links to resources and data that could help in understanding the distribution of exoplanets by mass.

Areas of Agreement / Disagreement

Participants express differing views on the reliability of the statistics regarding exoplanet ratios, with some suggesting that observational bias affects the data. No consensus is reached on the validity of the reported ratios or the implications of the findings.

Contextual Notes

Limitations include potential biases in observational data and the complexity of categorizing planets based on mass and density. The discussion does not resolve these issues.

Who May Find This Useful

Readers interested in exoplanet research, observational astronomy, and the statistical analysis of planetary distributions may find this discussion relevant.

Cerenkov
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Hello.

In this issue of the American Scientist magazine,
https://www.americanscientist.org/magazine/issues/2018/september-october, there's an article by Dominik Kraus of the Helmholtz-Zentrum Dresden-Rossendorf Institute of Radiation Physics about the internal composition of the planets Uranus and Neptune. In the opening paragraphs he writes...

The number of planets similar in size to Uranus and Neptune that have been found in the galaxy is roughly nine times greater than the number of much larger planets similar in size to Jupiter and Saturn.


This statistic interests me and I was wondering if other members of PF could help me explore further.
Are there any papers or articles that give other ratios? That is, the ratios of Jovians, Ice-Giants, Super-Earths and Earth-sized exoplanets to each other? Any help given would be appreciated, though I should point out that I'm coming at this from a basic level.

Thank you,

Cerenkov.
 
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Such statistic is in general very unreliable - because of observational bias. Larger planets are simply much easier to find. The Kepler survey has delivered less biased dataset for Neptune-sized planet and larger though, and i think reference you cited is referring specifically to Kepler data.

You can also see
https://en.wikipedia.org/wiki/Initial_mass_function
which shows opinions wildly different even to the jupiter-brown dwarf range.
 
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Thanks trurle.

Well, I suppose if I'm to pursue my interest further I'll just have to contact Dominik Kraus directly and ask him where he derived his ratio from.

Cerenkov.
 
trurle said:
...Larger planets are simply much easier to find. ...

That would suggest that the number neptunes is higher than the 10:1 ratio reported.

Cerenkov said:
...

This statistic interests me and I was wondering if other members of PF could help me explore further.
Are there any papers or articles that give other ratios? That is, the ratios of Jovians, Ice-Giants, Super-Earths and Earth-sized exoplanets to each other? Any help given would be appreciated, though I should point out that I'm coming at this from a basic level.
...

This website as the full list. You can sort by characteristic like mass or radius. I think wikipedia is more fun to read. You can surf directly to articles.

Planets do not cooperate and fall into neat categories. For example kepler 138b has gas planet densities but Earth like mass.
 
Many thanks, Stefan!

I can now work with these data and discover the ratios for myself.

Cerenkov.
 
Hey TEFling!

Not 5 minutes ago I ordered Yaqoob's book on Amazon.

It'll arrive, not just in time for Xmas, but more importantly, in time for me to better understand the TESS data release scheduled for January.

https://www.nasa.gov/ames/tess-pipeline

And that result is all down to you.

upload_2018-12-1_20-8-44.png
 

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