_version_ 1866911255448518656
author Fernandes, Rachel B.
Johnson, Samson
Bergsten, Galen J.
Bhure, Sakhee
Boley, Kiersten M.
Boss, Alan P.
Bryson, Steve
DeRocco, William
Dietrich, Jamie
Duck, Alison
Giacalone, Steven
Gupta, Arvind F.
He, Matthias Y.
Kunimoto, Michelle
Ment, Kristo
Sagear, Sheila
Silverstein, Michele L.
Sullivan, Kendall
Vrijmoet, Eliot Halley
Wagner, Kevin
Wilson, Robert F.
Brefka, Lucas
Belikov, Ruslan
Chakrabarty, Aritra
Christiansen, Jessie L.
Ciardi, David R.
Dattilo, Anne
Fitzmaurice, Evan
Ford, Eric B.
Hotnisky, Andrew
Jones, Sinclaire
Kar, Aman
Kopparapu, Ravi
Lowson, Nataliea
Mamajek, Eric E.
Mennesson, Bertrand
Meyer, Michael R.
Millholland, Sarah
Mulders, Gijs D.
Mullally, Susan E.
Murlidhar, Arjun
Pascucci, Ilaria
Ragozzine, Darin
Robertson, Paul
Stapelfeldt, Karl
Wright, Jason
author_facet Fernandes, Rachel B.
Johnson, Samson
Bergsten, Galen J.
Bhure, Sakhee
Boley, Kiersten M.
Boss, Alan P.
Bryson, Steve
DeRocco, William
Dietrich, Jamie
Duck, Alison
Giacalone, Steven
Gupta, Arvind F.
He, Matthias Y.
Kunimoto, Michelle
Ment, Kristo
Sagear, Sheila
Silverstein, Michele L.
Sullivan, Kendall
Vrijmoet, Eliot Halley
Wagner, Kevin
Wilson, Robert F.
Brefka, Lucas
Belikov, Ruslan
Chakrabarty, Aritra
Christiansen, Jessie L.
Ciardi, David R.
Dattilo, Anne
Fitzmaurice, Evan
Ford, Eric B.
Hotnisky, Andrew
Jones, Sinclaire
Kar, Aman
Kopparapu, Ravi
Lowson, Nataliea
Mamajek, Eric E.
Mennesson, Bertrand
Meyer, Michael R.
Millholland, Sarah
Mulders, Gijs D.
Mullally, Susan E.
Murlidhar, Arjun
Pascucci, Ilaria
Ragozzine, Darin
Robertson, Paul
Stapelfeldt, Karl
Wright, Jason
contents Searching for life elsewhere in the universe is one of the most highly prioritized pursuits in astronomy today. However, the ability to observe evidence of Earth-like life through biosignatures is limited by the number of planets in the solar neighborhood with conditions similar to Earth. The occurrence rate of Earth-like planets in the habitable zones of Sun-like stars, $η_{\oplus}$, is therefore crucial for addressing the apparent lack of consensus on its value in the literature. Here we present a review of the current understanding of $η_{\oplus}$. We first provide definitions for parameters that contribute to $η_{\oplus}$. Then, we discuss the previous and current estimated parameter values and the context of the limitations on the analyses that produced these estimates. We compile an extensive list of the factors that go into any calculation of $η_{\oplus}$, and how detection techniques and surveys differ in their sensitivity and ability to accurately constrain $η_{\oplus}$. Understanding and refining the value of $η_{\oplus}$ is crucial for upcoming missions and telescopes, such as the planned Habitable Worlds Observatory and the Large Interferometer for Exoplanets, which aim to search for biosignatures on exoplanets in the solar neighborhood.
format Preprint
id arxiv_https___arxiv_org_abs_2511_05660
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Are We There Yet? Challenges in Quantifying the Frequency of Earth Analogs in the Habitable Zone
Fernandes, Rachel B.
Johnson, Samson
Bergsten, Galen J.
Bhure, Sakhee
Boley, Kiersten M.
Boss, Alan P.
Bryson, Steve
DeRocco, William
Dietrich, Jamie
Duck, Alison
Giacalone, Steven
Gupta, Arvind F.
He, Matthias Y.
Kunimoto, Michelle
Ment, Kristo
Sagear, Sheila
Silverstein, Michele L.
Sullivan, Kendall
Vrijmoet, Eliot Halley
Wagner, Kevin
Wilson, Robert F.
Brefka, Lucas
Belikov, Ruslan
Chakrabarty, Aritra
Christiansen, Jessie L.
Ciardi, David R.
Dattilo, Anne
Fitzmaurice, Evan
Ford, Eric B.
Hotnisky, Andrew
Jones, Sinclaire
Kar, Aman
Kopparapu, Ravi
Lowson, Nataliea
Mamajek, Eric E.
Mennesson, Bertrand
Meyer, Michael R.
Millholland, Sarah
Mulders, Gijs D.
Mullally, Susan E.
Murlidhar, Arjun
Pascucci, Ilaria
Ragozzine, Darin
Robertson, Paul
Stapelfeldt, Karl
Wright, Jason
Earth and Planetary Astrophysics
Instrumentation and Methods for Astrophysics
Solar and Stellar Astrophysics
Searching for life elsewhere in the universe is one of the most highly prioritized pursuits in astronomy today. However, the ability to observe evidence of Earth-like life through biosignatures is limited by the number of planets in the solar neighborhood with conditions similar to Earth. The occurrence rate of Earth-like planets in the habitable zones of Sun-like stars, $η_{\oplus}$, is therefore crucial for addressing the apparent lack of consensus on its value in the literature. Here we present a review of the current understanding of $η_{\oplus}$. We first provide definitions for parameters that contribute to $η_{\oplus}$. Then, we discuss the previous and current estimated parameter values and the context of the limitations on the analyses that produced these estimates. We compile an extensive list of the factors that go into any calculation of $η_{\oplus}$, and how detection techniques and surveys differ in their sensitivity and ability to accurately constrain $η_{\oplus}$. Understanding and refining the value of $η_{\oplus}$ is crucial for upcoming missions and telescopes, such as the planned Habitable Worlds Observatory and the Large Interferometer for Exoplanets, which aim to search for biosignatures on exoplanets in the solar neighborhood.
title Are We There Yet? Challenges in Quantifying the Frequency of Earth Analogs in the Habitable Zone
topic Earth and Planetary Astrophysics
Instrumentation and Methods for Astrophysics
Solar and Stellar Astrophysics
url https://arxiv.org/abs/2511.05660