planet demographics
(planet occurrence rate, exoplanet demographics, exoplanet occurrence rate)
(statistics regarding the number of planets)
Planet demographics, the occurrence rate of planets
(especially including extra-solar planets) and occurrence rate of
specific planet characteristics,
grows in interest with the ongoing improvements in detecting and observing them,
with thousands now known and a growing number with reasonable
mass and radius estimates, and/or transmission spectrography data.
Such demographic study is a work in progress:
new data constantly becomes available, and the current data is
incomplete due to specific gaps, two obvious
ones being the smallest planets and the planets furthest from the
host star. The field is new and researchers are producing
varying numbers, but there is some consensus regarding some general
characteristics. Individual studies often have caveats regarding
the type of stars and planets: specifying particular planet radius
and/or mass, planet orbital period, and/or spectral class
of host star.
Over time, I've heard some generalities regarding the most
common main-sequence spectral classes
(F-type through M-type stars which account for 99% of main
sequence stars):
- planets are common: the mean number of planets per such stars is likely at least one, perhaps two or more.
- smaller planets (rocky planets) are far more common than larger ones, very likely hosted by at least half of such stars.
- giant planets are rarer, likely hosted by on the order of a tenth of such stars.
- super-Earths (somewhat larger than Earth) are the most common, possibility hosted by as many as two thirds of such stars.
- both small and large planets occur more often hosted by higher metallicity stars.
(statistics,planets,exoplanets)
Further reading:
http://exoplanetarchive.ipac.caltech.edu/docs/counts_detail.html
http://exoplanetarchive.ipac.caltech.edu/docs/occurrence_rate_papers.html
https://nexsci.caltech.edu/workshop/2021/enielsen_sagan_workshop_2021.pdf
https://exoplanets.nasa.gov/system/presentations/files/143_20200103-1120_Bhattacharya_Exopag21.pdf
https://ui.adsabs.harvard.edu/abs/2021exbi.book....2G/abstract
https://ui.adsabs.harvard.edu/abs/2019BAAS...51c.505B/abstract
https://arxiv.org/abs/2304.12442
Referenced by pages:
extra-solar planet
giant planet formation
Index