Earth analogs
The Occurrence Rate of Earth Analog Planets Orbiting Sunlike Stars
Authors: Joseph Catanzarite, Michael Shao (Jet Propulsion Laboratory, California Institute of Technology)
Abstract: Kepler is a space telescope that searches Sun-like stars for planets. Its major goal is to determine the fraction of Sunlike stars that have planets like Earth... Here, we show that 1.4% to 2.7% of stars like the Sun are expected to have Earth analog planets, based on the Kepler data release of Feb 2011.
The full paper is at http://arxiv.org/ftp/arxiv/papers/1103/1103.1443.pdf. Note that by "sunlike" the study means FGK stars.
Let's say the actual percentage is 2.05%, which is the halfway point between the upper and lower limits. Solstation.com tells us there are 303 known F stars within 100 light years of Sol, 512 G stars and 947 K stars. That comes to 1762 stars. If 2.05% of them have Earth analog planets, that's 36 of them within 100 light years. Note that there are likely to be many sunlike stars that haven't been discovered, particularly K stars more than 50 light years out.
Keeping it closer to home, there are at least 254 FGK stars within 50 light years. 2.05% of that would give us 5 Earth analogs.
Authors: Joseph Catanzarite, Michael Shao (Jet Propulsion Laboratory, California Institute of Technology)
Abstract: Kepler is a space telescope that searches Sun-like stars for planets. Its major goal is to determine the fraction of Sunlike stars that have planets like Earth... Here, we show that 1.4% to 2.7% of stars like the Sun are expected to have Earth analog planets, based on the Kepler data release of Feb 2011.
The full paper is at http://arxiv.org/ftp/arxiv/papers/1103/1103.1443.pdf. Note that by "sunlike" the study means FGK stars.
Let's say the actual percentage is 2.05%, which is the halfway point between the upper and lower limits. Solstation.com tells us there are 303 known F stars within 100 light years of Sol, 512 G stars and 947 K stars. That comes to 1762 stars. If 2.05% of them have Earth analog planets, that's 36 of them within 100 light years. Note that there are likely to be many sunlike stars that haven't been discovered, particularly K stars more than 50 light years out.
Keeping it closer to home, there are at least 254 FGK stars within 50 light years. 2.05% of that would give us 5 Earth analogs.