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Del Genio AD, Kiang NY, Way MJ, Amundsen DS, Sohl LE, Fujii Y, Chandler M, Aleinov I, Colose CM, Guzewich SD, Kelley M. Albedos, Equilibrium Temperatures, and Surface Temperatures of Habitable Planets. THE ASTROPHYSICAL JOURNAL 2019; 884:75. [PMID: 33100349 PMCID: PMC7580787 DOI: 10.3847/1538-4357/ab3be8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The potential habitability of known exoplanets is often categorized by a nominal equilibrium temperature assuming a Bond albedo of either ∼0.3, similar to Earth, or 0. As an indicator of habitability, this leaves much to be desired, because albedos of other planets can be very different, and because surface temperature exceeds equilibrium temperature due to the atmospheric greenhouse effect. We use an ensemble of general circulation model simulations to show that for a range of habitable planets, much of the variability of Bond albedo, equilibrium temperature and even surface temperature can be predicted with useful accuracy from incident stellar flux and stellar temperature, two known parameters for every confirmed exoplanet. Earth's Bond albedo is near the minimum possible for habitable planets orbiting G stars, because of increasing contributions from clouds and sea ice/snow at higher and lower instellations, respectively. For habitable M star planets, Bond albedo is usually lower than Earth's because of near-IR H2O absorption, except at high instellation where clouds are important. We apply relationships derived from this behavior to several known exoplanets to derive zeroth-order estimates of their potential habitability. More expansive multivariate statistical models that include currently non-observable parameters show that greenhouse gas variations produce significant variance in albedo and surface temperature, while increasing length of day and land fraction decrease surface temperature; insights for other parameters are limited by our sampling. We discuss how emerging information from global climate models might resolve some degeneracies and help focus scarce observing resources on the most promising planets.
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Affiliation(s)
- Anthony D Del Genio
- NASA Goddard Institute for Space Studies, 2880 Broadway, New York, NY 10025, USA
| | - Nancy Y Kiang
- NASA Goddard Institute for Space Studies, 2880 Broadway, New York, NY 10025, USA
| | - Michael J Way
- NASA Goddard Institute for Space Studies, 2880 Broadway, New York, NY 10025, USA
| | - David S Amundsen
- NASA Goddard Institute for Space Studies, 2880 Broadway, New York, NY 10025, USA
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY 10027, USA
| | - Linda E Sohl
- NASA Goddard Institute for Space Studies, 2880 Broadway, New York, NY 10025, USA
- Center for Climate Systems Research, Columbia University, New York, NY 10027, USA
| | - Yuka Fujii
- Earth-Life Science Institute, Tokyo Institute of Technology, Ookayama, Meguro, Tokyo 152-8550, Japan
| | - Mark Chandler
- NASA Goddard Institute for Space Studies, 2880 Broadway, New York, NY 10025, USA
- Center for Climate Systems Research, Columbia University, New York, NY 10027, USA
| | - Igor Aleinov
- NASA Goddard Institute for Space Studies, 2880 Broadway, New York, NY 10025, USA
- Center for Climate Systems Research, Columbia University, New York, NY 10027, USA
| | - Christopher M Colose
- NASA Postdoctoral Program, Goddard Institute for Space Studies, New York, NY 10025, USA
| | | | - Maxwell Kelley
- NASA Goddard Institute for Space Studies, 2880 Broadway, New York, NY 10025, USA
- SciSpace LLC, 2880 Broadway, New York, NY 10025, USA
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Thompson SE, Coughlin JL, Hoffman K, Mullally F, Christiansen JL, Burke CJ, Bryson S, Batalha N, Haas MR, Catanzarite J, Rowe JF, Barentsen G, Caldwell DA, Clarke BD, Jenkins JM, Li J, Latham DW, Lissauer JJ, Mathur S, Morris RL, Seader SE, Smith JC, Klaus TC, Twicken JD, Van Cleve JE, Wohler B, Akeson R, Ciardi DR, Cochran WD, Henze CE, Howell SB, Huber D, Prša A, Ramírez SV, Morton TD, Barclay T, Campbell JR, Chaplin WJ, Charbonneau D, Christensen-Dalsgaard J, Dotson JL, Doyle L, Dunham EW, Dupree AK, Ford EB, Geary JC, Girouard FR, Isaacson H, Kjeldsen H, Quintana EV, Ragozzine D, Shporer A, Aguirre VS, Steffen JH, Still M, Tenenbaum P, Welsh WF, Wolfgang A, Zamudio KA, Koch DG, Borucki WJ. PLANETARY CANDIDATES OBSERVED BY Kepler. VIII. A FULLY AUTOMATED CATALOG WITH MEASURED COMPLETENESS AND RELIABILITY BASED ON DATA RELEASE 25. THE ASTROPHYSICAL JOURNAL. SUPPLEMENT SERIES 2018; 235:38. [PMID: 32908325 PMCID: PMC7477822 DOI: 10.3847/1538-4365/aab4f9] [Citation(s) in RCA: 255] [Impact Index Per Article: 42.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We present the Kepler Object of Interest (KOI) catalog of transiting exoplanets based on searching four years of Kepler time series photometry (Data Release 25, Q1-Q17). The catalog contains 8054 KOIs of which 4034 are planet candidates with periods between 0.25 and 632 days. Of these candidates, 219 are new in this catalog and include two new candidates in multi-planet systems (KOI-82.06 and KOI-2926.05), and ten new high-reliability, terrestrial-size, habitable zone candidates. This catalog was created using a tool called the Robovetter which automatically vets the DR25 Threshold Crossing Events (TCEs) found by the Kepler Pipeline (Twicken et al. 2016). Because of this automation, we were also able to vet simulated data sets and therefore measure how well the Robovetter separates those TCEs caused by noise from those caused by low signal-to-noise transits. Because of these measurements we fully expect that this catalog can be used to accurately calculate the frequency of planets out to Kepler's detection limit, which includes temperate, super-Earth size planets around GK dwarf stars in our Galaxy. This paper discusses the Robovetter and the metrics it uses to decide which TCEs are called planet candidates in the DR25 KOI catalog. We also discuss the simulated transits, simulated systematic noise, and simulated astrophysical false positives created in order to characterize the properties of the final catalog. For orbital periods less than 100 d the Robovetter completeness (the fraction of simulated transits that are determined to be planet candidates) across all observed stars is greater than 85%. For the same period range, the catalog reliability (the fraction of candidates that are not due to instrumental or stellar noise) is greater than 98%. However, for low signal-to-noise candidates found between 200 and 500 days, our measurements indicate that the Robovetter is 73.5% complete and 37.2% reliable across all searched stars (or 76.7% complete and 50.5% reliable when considering just the FGK dwarf stars). We describe how the measured completeness and reliability varies with period, signal-to-noise, number of transits, and stellar type. Also, we discuss a value called the disposition score which provides an easy way to select a more reliable, albeit less complete, sample of candidates. The entire KOI catalog, the transit fits using Markov chain Monte Carlo methods, and all of the simulated data used to characterize this catalog are available at the NASA Exoplanet Archive.
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Affiliation(s)
- Susan E. Thompson
- SETI Institute, 189 Bernardo Ave, Suite 200, Mountain View, CA 94043, USA
- NASA Ames Research Center, Moffett Field, CA 94035, USA
- Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218
| | - Jeffrey L. Coughlin
- SETI Institute, 189 Bernardo Ave, Suite 200, Mountain View, CA 94043, USA
- NASA Ames Research Center, Moffett Field, CA 94035, USA
| | - Kelsey Hoffman
- SETI Institute, 189 Bernardo Ave, Suite 200, Mountain View, CA 94043, USA
| | - Fergal Mullally
- SETI Institute, 189 Bernardo Ave, Suite 200, Mountain View, CA 94043, USA
- NASA Ames Research Center, Moffett Field, CA 94035, USA
- Orbital Insight, 100 W Evelyn Ave #110, Mountain View, CA 94041
| | | | - Christopher J. Burke
- SETI Institute, 189 Bernardo Ave, Suite 200, Mountain View, CA 94043, USA
- NASA Ames Research Center, Moffett Field, CA 94035, USA
- MIT Kavli Institute for Astrophysics and Space Research, 77 Massachusetts Avenue, 37-241, Cambridge, MA 02139
| | - Steve Bryson
- NASA Ames Research Center, Moffett Field, CA 94035, USA
| | | | | | - Joseph Catanzarite
- SETI Institute, 189 Bernardo Ave, Suite 200, Mountain View, CA 94043, USA
- NASA Ames Research Center, Moffett Field, CA 94035, USA
| | - Jason F. Rowe
- Dept. of Physics and Astronomy, Bishop’s University, 2600 College St., Sherbrooke, QC, J1M 1Z7, Canada
| | - Geert Barentsen
- Bay Area Environmental Research Institute, 625 2nd St., Ste 209, Petaluma, CA 94952, USA
| | - Douglas A. Caldwell
- SETI Institute, 189 Bernardo Ave, Suite 200, Mountain View, CA 94043, USA
- NASA Ames Research Center, Moffett Field, CA 94035, USA
| | - Bruce D. Clarke
- SETI Institute, 189 Bernardo Ave, Suite 200, Mountain View, CA 94043, USA
- NASA Ames Research Center, Moffett Field, CA 94035, USA
| | | | - Jie Li
- SETI Institute, 189 Bernardo Ave, Suite 200, Mountain View, CA 94043, USA
| | - David W. Latham
- Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge MA 02138, USA
| | | | - Savita Mathur
- Space Science Institute, 4750 Walnut Street, Suite 205, Boulder, CO 80301, USA
| | - Robert L. Morris
- SETI Institute, 189 Bernardo Ave, Suite 200, Mountain View, CA 94043, USA
- NASA Ames Research Center, Moffett Field, CA 94035, USA
| | - Shawn E. Seader
- Rincon Research Corporation,101 N Wilmot Rd, Tucson, AZ 85711
| | - Jeffrey C. Smith
- SETI Institute, 189 Bernardo Ave, Suite 200, Mountain View, CA 94043, USA
- NASA Ames Research Center, Moffett Field, CA 94035, USA
| | - Todd C. Klaus
- NASA Ames Research Center, Moffett Field, CA 94035, USA
| | - Joseph D. Twicken
- SETI Institute, 189 Bernardo Ave, Suite 200, Mountain View, CA 94043, USA
- NASA Ames Research Center, Moffett Field, CA 94035, USA
| | | | - Bill Wohler
- SETI Institute, 189 Bernardo Ave, Suite 200, Mountain View, CA 94043, USA
- NASA Ames Research Center, Moffett Field, CA 94035, USA
| | - Rachel Akeson
- IPAC-NExScI, Mail Code 100-22, Caltech, 1200 E. California Blvd. Pasadena, CA 91125
| | - David R. Ciardi
- IPAC-NExScI, Mail Code 100-22, Caltech, 1200 E. California Blvd. Pasadena, CA 91125
| | - William D. Cochran
- McDonald Observatory and Department of Astronomy, University of Texas at Austin, Austin, TX 78712
| | | | | | - Daniel Huber
- SETI Institute, 189 Bernardo Ave, Suite 200, Mountain View, CA 94043, USA
- Institute for Astronomy, University of Hawai‘i, 2680 Woodlawn Drive, Honolulu, HI 96822, USA
- Sydney Institute for Astronomy (SIfA), School of Physics, University of Sydney, NSW 2006, Australia
- Stellar Astrophysics Centre, Dept. of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000 Aarhus C, Denmark
| | - Andrej Prša
- Villanova University, Dept. of Astrophysics and Planetary Science, 800 Lancaster Ave, Villanova PA 19085
| | - Solange V. Ramírez
- IPAC-NExScI, Mail Code 100-22, Caltech, 1200 E. California Blvd. Pasadena, CA 91125
| | - Timothy D. Morton
- Department of Astrophysical Sciences, Princeton University, 4 Ivy Lane, Princeton, NJ 08544, USA
| | - Thomas Barclay
- NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771
| | - Jennifer R. Campbell
- NASA Ames Research Center, Moffett Field, CA 94035, USA
- KRBwyle, 2400 Nasa Parkway, Houston, TX 77058 USA
| | - William J. Chaplin
- Stellar Astrophysics Centre, Dept. of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000 Aarhus C, Denmark
- School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - David Charbonneau
- Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge MA 02138, USA
| | - Jørgen Christensen-Dalsgaard
- Stellar Astrophysics Centre, Dept. of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000 Aarhus C, Denmark
| | | | - Laurance Doyle
- SETI Institute, 189 Bernardo Ave, Suite 200, Mountain View, CA 94043, USA
- Institute for the Metaphysics of Physics, Principia College, One Maybeck Place, Elsah, Illinois 62028
| | | | - Andrea K. Dupree
- Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge MA 02138, USA
| | - Eric B. Ford
- Dept. of Astronomy & Astrophysics, 525 Davey Laboratory, The Pennsylvania State University, University Park, PA, 16802, USA
- Center for Exoplanets and Habitable Worlds, 525 Davey Laboratory, The Pennsylvania State University, University Park, PA, 16802, USA
- Center for Astrostatistics, 525 Davey Laboratory, The Pennsylvania State University, University Park, PA, 16802, USA
- Institute for CyberScience, The Pennsylvania State University
| | - John C. Geary
- Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge MA 02138, USA
| | - Forrest R. Girouard
- NASA Ames Research Center, Moffett Field, CA 94035, USA
- Orbital Sciences Corporation, 2401 East El Segundo Boulevard, Suite 200, El Segundo, CA 90245, USA
| | | | - Hans Kjeldsen
- Stellar Astrophysics Centre, Dept. of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000 Aarhus C, Denmark
| | - Elisa V. Quintana
- NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771
| | - Darin Ragozzine
- Brigham Young University, Department of Physics and Astronomy, N283 ESC, Provo, UT 84602, USA
| | - Avi Shporer
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA
| | - Victor Silva Aguirre
- Stellar Astrophysics Centre, Dept. of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000 Aarhus C, Denmark
| | - Jason H. Steffen
- University of Nevada, Las Vegas, 4505 S Maryland Pkwy, Las Vegas, NV 89154
| | - Martin Still
- Bay Area Environmental Research Institute, 625 2nd St., Ste 209, Petaluma, CA 94952, USA
| | - Peter Tenenbaum
- SETI Institute, 189 Bernardo Ave, Suite 200, Mountain View, CA 94043, USA
- NASA Ames Research Center, Moffett Field, CA 94035, USA
| | - William F. Welsh
- Department of Astronomy, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182-1221
| | - Angie Wolfgang
- Dept. of Astronomy & Astrophysics, 525 Davey Laboratory, The Pennsylvania State University, University Park, PA, 16802, USA
- Center for Exoplanets and Habitable Worlds, 525 Davey Laboratory, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Khadeejah A Zamudio
- NASA Ames Research Center, Moffett Field, CA 94035, USA
- KRBwyle, 2400 Nasa Parkway, Houston, TX 77058 USA
| | - David G. Koch
- NASA Ames Research Center, Moffett Field, CA 94035, USA
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