More than half of all sunlike stars in the Milky Way may have a habitable planet

[Admin]

On average, each sunlike star in the Milky Way likely harbors between 0.4 and 0.9 rocky planets in its "habitable zone," researchers have found.

More than half of all sunlike stars in the Milky Way may have a habitable planet : Read more

 

[rod]

The study here indicates there could be as many as 300 million exoplanets that there could be life on or at least *habitable*.

https://phys.org/news/2020-10-habitable-planets.html, "Thanks to new research using data from the Kepler space telescope, it's estimated that there could be as many as 300 million potentially habitable planets in our galaxy. Some could even be pretty close, with several likely within 30 light-years of our Sun. The findings will be published in The Astronomical Journal, and research was a collaboration of scientists from NASA, the SETI Institute, and other organizations worldwide. "This is the first time that all of the pieces have been put together to provide a reliable measurement of the number of potentially habitable planets in the galaxy," said co-author Jeff Coughlin, an exoplanet researcher at the SETI Institute and Director of Kepler's Science Office. "This is a key term of the Drake Equation, used to estimate the number of communicable civilizations—we're one step closer on the long road to finding out if we're alone in the cosmos."

The Occurrence of Rocky Habitable Zone Planets Around Solar-Like Stars from Kepler Data, https://arxiv.org/abs/2010.14812, “We present occurrence rates for rocky planets in the habitable zones (HZ) of main-sequence dwarf stars based on the Kepler DR25 planet candidate catalog and Gaia-based stellar properties. We provide the first analysis in terms of star-dependent instellation flux, which allows us to track HZ planets. We define η⊕ as the HZ occurrence of planets with radius between 0.5 and 1.5 R⊕ orbiting stars with effective temperatures between 4800 K and 6300 K. We find that η⊕ for the conservative HZ is between 0.37+0.48/−0.21 (errors reflect 68\% credible intervals) and 0.60+0.90/−0.36 planets per star, while the optimistic HZ occurrence is between 0.58+0.73/−0.33 and 0.88+1.28/−0.51 planets per star. These bounds reflect two extreme assumptions about the extrapolation of completeness beyond orbital periods where DR25 completeness data are available. The large uncertainties are due to the small number of detected small HZ planets. We find similar occurrence rates using both a Poisson likelihood Bayesian analysis and Approximate Bayesian Computation. Our results are corrected for catalog completeness and reliability. Both completeness and the planet occurrence rate are dependent on stellar effective temperature. We also present occurrence rates for various stellar populations and planet size ranges. We estimate with 95% confidence that, on average, the nearest HZ planet around G and K dwarfs is about 6 pc away, and there are about 4 HZ rocky planets around G and K dwarfs within 10 pc of the Sun.”

My observation. Confirming the possible 300 million habitable exoplanets in the Milky Way remains challenging. Exoplanet databases like these show how difficult it is to confirm a habitable exoplanet. Presently it is a small number listed compared to the 300 million possible figure.

Catalogue of Exoplanets

Sortable and filterable catalogue of the exoplanet discovered so far.

exoplanet.eu

NASA Exoplanet Archive

exoplanetarchive.ipac.caltech.edu

 

[Trevize62]

We should make a distinction between planets that could host life, and those that could be habitable for human beings (certainly much less common).
Many worlds could be plenty of lifeforms but inhabitable for humans because, for example, their atmosphere contains too much oxygen, or too few, or could have a too strong or too weak gravity, an atmosfere too dense or not enough dense, dangerous lifeforms and so on.