1. Inhabited exomoon by artist Dan Durda

2. Imagine a terrestrial-type exomoon orbiting a Jovian-type planet within the habitable zone of a star. This exomoon has a thick, cloudy atmosphere that completely fills the sky, except for breaks in the clouds that occur about once every 400 years. When a break does occur, it is short-lived and reveals only a small area of the sky. Describe the civilization on this exomoon that has rarely seen beyond the clouds, including its culture and value system. Thought-experiment: Develop a short story using this theme and the accompanying data on the next slide

3. F5 star Mass ~2.8 x 10 30 kg, luminosity ~ 3.0 x 10 27 watts, and radius ~ 1.4 x 10 9 meters. Jovian planet Mass ~1.6 x 10 27 kg, density ~1.2 grams/cm 3, radius ~ 6.9 x 10 7 meters, semi-major axis of planet’s orbit ~ 2.5 x 10 11 meters, and orbital eccentricity ~ 0.00. Terrestrial-type exomoon Mass ~ 8.4 x 10 24 kg, albedo ~ 0.67, semi-major axis of exomoon’s orbit ~ 5.8 x 10 9 meters, orbital eccentricity ~ 0.00, radius = 7.27 x 10 6 meters, and rigidity of exomoon ~ 3 x 10 10 Newtons/meter 2. The exomoon has land and oceans. F5 star Mass ~2.8 x 10 30 kg, luminosity ~ 3.0 x 10 27 watts, and radius ~ 1.4 x 10 9 meters. Jovian planet Mass ~1.6 x 10 27 kg, density ~1.2 grams/cm 3, radius ~ 6.9 x 10 7 meters, semi-major axis of planet’s orbit ~ 2.5 x 10 11 meters, and orbital eccentricity ~ 0.00. Terrestrial-type exomoon Mass ~ 8.4 x 10 24 kg, albedo ~ 0.67, semi-major axis of exomoon’s orbit ~ 5.8 x 10 9 meters, orbital eccentricity ~ 0.00, radius = 7.27 x 10 6 meters, and rigidity of exomoon ~ 3 x 10 10 Newtons/meter 2. The exomoon has land and oceans.

5. Sagan C., et al. (1993) A search for life on Earth from the Galileo spacecraft. Nature, 365, 715-721. “In its December 1990 fly-by of Earth, the Galileo spacecraft found evidence of abundant gaseous oxygen, a widely distributed surface pigment with a sharp absorption edge in the red part of the visible spectrum, and atmospheric methane in extreme thermodynamic disequilibrium; together, these are strongly suggestive of life on Earth.”

6. Sagan C., et al. (1993) A search for life on Earth from the Galileo spacecraft. Nature, 365, 715-721.

7. Inhabited exomoon by artist Dan Durda

8. Kaltenegger L., et al. (2010) Deciphering spectral fingerprints of habitable exoplanets. Astrobiology, 10(1), 89-102.

9. Earth’s spectral signatures Visible Near infrared

10. Kaltenegger L., et al. (2010) Deciphering spectral fingerprints of habitable exoplanets. Astrobiology, 10(1), 89-102. Earth’s infrared spectrum (black line) at 6-20 µm Infrared

11. Kaltenegger L., et al. (2010) Deciphering spectral fingerprints of habitable exoplanets. Astrobiology, 10(1), 89-102. Comparisons of thermal infrared emissions as an indicator of oceans and/or thick atmosphere (right) during 1 orbital phase (left)

12. Kaltenegger L., et al. (2010) Deciphering spectral fingerprints of habitable exoplanets. Astrobiology, 10(1), 89-102.

13. Oxygen cycle on Earth

14. Changes in the Earth’s atmospheric (O 2 /N 2 ) ratio during 2000-2004

15. Kaltenegger L., et al. (2010) Deciphering spectral fingerprints of habitable exoplanets. Astrobiology, 10(1), 89-102. Hypothesized changes in Earth’s visible and infrared spectra through its geological history

16. Kaltenegger L. (2010) Characterizing habitable exomoons. Astrophysical Journal Letters, 712, L125-L130. Contrast ratio of absorption features by an Earth-like atmosphere during transit of an exomoon for M9, M5, and solar-type stars

17. Kaltenegger L. (2010) Characterizing habitable exomoons. Astrophysical Journal Letters, 712, L125-L130. Parameters associated with transits of Jupiter-sized exoplanets orbiting in the Earth-equivalent habitable zone of M0-M9 stars

18. Kaltenegger L. (2010) Characterizing habitable exomoons. Astrophysical Journal Letters, 712, L125-L130. Maximum orbital separation of an Earth-like exomoon (in prograde and retrograde orbits) from its Jovian host-planet (in stellar radii) for 1M J and 13M J

19. Kaltenegger L. (2010) Characterizing habitable exomoons. Astrophysical Journal Letters, 712, L125-L130. “… habitable exomoons around M stars would be tidally locked to their planet, not to their host star, removing the problem of a potential freeze out of the atmosphere on the dark side of an Earth-like exomoon,…”

20. Kaltenegger L. (2010) Characterizing habitable exomoons. Astrophysical Journal Letters, 712, L125-L130. R H = Hill radius = maximum stable distance of a satellite from its host-planet M p = mass of host-planet M star = mass of star e p = eccentricity of planet’s orbit e Sat = eccentricity of exomoon’s orbit a eR = critical semi-major axis of satellite with retrograde orbit a eP = critical semi-major axis of satellite with prograde orbit R H = Hill radius = maximum stable distance of a satellite from its host-planet M p = mass of host-planet M star = mass of star e p = eccentricity of planet’s orbit e Sat = eccentricity of exomoon’s orbit a eR = critical semi-major axis of satellite with retrograde orbit a eP = critical semi-major axis of satellite with prograde orbit