The Age of Exoplanets: From First Discoveries to the Search for Living Worlds
Dr. Avi Mandell (NASA) “Somewhere, something incredible is waiting to be known.” - Carl Sagan
How will the discovery of a distant planet teeming with life change our perspective on our own planet – and on ourselves? Planets 101: Our Solar SysteM Planets 101: Our Solar SysteM First Planet Around a Sun-Like Star Discovered in 1995 Notable Facts About 1995:
• Bill Clinton is in his 3rd year of the Presidency
• Ebay opens for business
•DVDs are first introduced
•Big event for the coffee-drinking world… Invention of the Frappucino! The First Planets were Discovered by Measuring The Motions of Stars
51 Peg b • Uses the change in star’s light due to the Doppler effect
Mayor & Queloz, Movie: eso1035g.mov November 1995
Dr. Michel Mayor & Dr. Didier Queloz Geneva Observatory
Spectrum of Starlight from Dr. Geoff Marcy & Parent Star Dr. R. Paul Butler San Francisco State Univ. Timeline of Exoplanet Discoveries
Known Exoplanets, 1995: 0
Planet Mass
Jup.
Neptune
Earth Mercury Earth Jupiter Distance to the Star Timeline of Exoplanet Discoveries
Known Exoplanets, 1996: 6
Planet Mass
Jup.
First Confirmed RV Planet: 51 Peg b
Neptune
Earth Mercury Earth Jupiter Distance to the Star Timeline of Exoplanet Discoveries
Known Exoplanets, 1996: 6 2000: 38
Planet Mass
First Transiting Planet: Jup. HD 209458 b
First Confirmed RV Planet: 51 Peg b
Neptune
Earth Mercury Earth Jupiter Distance to the Star The Most Planets have been Discovered by Measuring The Shadows on Stars
Movie: OccultationGraphH264FullSize.mov Timeline of Exoplanet Discoveries
Known Exoplanets, 2000: 38 2005: 155 2008: 260 2012: 579
Planet Mass
Jup.
Neptune
Earth Mercury Earth Jupiter Distance to the Star Revolutionizing Exoplanet Discovery: The Kepler Space Telescope
• Launched in March 2009 • Stared at one patch of the sky (~150,000 stars) for a total of 5 years and watched for planetary transits Revolutionizing Exoplanet Discovery: The Kepler Space Telescope
Kepler Has Discovered 4,696 Planet Candidates as of July 2015 Statistics of Planetary Systems: The Kepler Space Telescope
Candidate Planets Feb 2012 Statistics of Planetary Systems: The Kepler Space Telescope
Candidate Planets Feb 2012
Io M E Kepler’s Super-Earth Planets: Neptune-Like or Earth-Like?
Kepler-11 e
Kepler-11 d Kepler-11 c
Kep-11 f
Kepler-11 b
*confirmed planets Lissauer et al. 2011 Kepler’s Super-Earth Planets: Neptune-Like or Earth-Like?
The Temperate Sweet Spot: The Habitable Zone
Water Water Boils Freezes Finding Nearby Transiting Earth-Like Planets We need planets that are rocky and nearby… “Good planets are hard to find, and hard planets are good to find”
Before 2009
50% Fe 100% H2O
Berta-Thompson et al. 2015 Finding Nearby Transiting Earth-Like Planets We need planets that are rocky and nearby… “Good planets are hard to find, and hard planets are good to find”
AfterBefore 2009 2009
50% Fe 100% H2O
Berta-Thompson et al. 2015 What Does a Living Planet’s Atmosphere Look (or Smell) Like? How Do We Learn About The Atmospheres of Transiting Planets? • Transits provide the – As starlight passes – The more absorption, opportunity to probe through the the larger a planet’s the absorption in a atmosphere of a planet, radius appears, and the planet’s atmosphere atoms and molecules higher the altitude that absorb at different the transmitted light wavelengths passes through
Apparent Planet Size Revolutionizing Exoplanet Atmospheres: The James Webb Space Telescope
• Expected launch in 2018, first light in early 2019 • More than 100x more sensitive than any previous IR telescope
Simulated Habitable Super-Earth (Teq ~ 300K) around an M-star at 20 pc with JWST
H2O H2O CO2 Abs. Abs. Abs.
Deming et al. 2009 How to See Earth-Sized planets around Sun-like Stars Coronographic Imaging Remaining light Light is focused… at edge and center… Problem: The final image: Initial Stellar almost all starlight is removed, Illumination – revealing the planet Too bright!
planet? planet!
… and mostly … is blocked again! star blocked
(Simulated image)
Occulting Spot Adapted from Lyot Stop Lyot.org How to See Earth-Sized planets around Sun-like Stars Coronographic Imaging Remaining light Light is focused… at edge and center… Problem: The final image: Beta Pictoris b almost all starlight is removed, Initial Stellar Illumination – revealing the planet ~ 8MJ, ~ 10 AU Too bright!
planet? planet!
… and mostly … is blocked again! star blocked
(Simulated image)
Occulting Spot Adapted from Lyot Stop Lyot.org Bonnefoy et al. 2011 – Optimal technique for finding colder planets at larger distances from their parent star
– Earth-like planets will require HR 8799 b,c,d,e All planets ~ 8 M technology 10,000x more precise J than the current best performance Marois et al. 2010 Marching Towards The Ultimate Goal: Measuring the Atmosphere on a Living Planet
Timeline of Exoplanet Discovery
1990 Hubble Launched
First Exoplanet Found
2000 First Transiting ExPl. Spitzer Launched First Light from an ExPl.
Kepler Launched 2010 First Spectrum of a Super-Earth First Earth-sized ExPl Found First Habitable Earth-sized ExPl ? JWST Planned Launch 2020 First Spectrum of a Habitable M-Earth?
2030 N. Gen. Telescope Launched? First Spectrum of a Habitable Earth? Marching Towards The Ultimate Goal: Measuring the Atmosphere on a Living Planet
• Timeline of Exoplanet Discovery The goal is to acquire both an image and a spectrum of a nearby Earth-sized planet, in order 1990 Hubble Launched to search for definitive signs of life
First Exoplanet Found Thermal Emission at 300K 2000 First Transiting ExPl. Spitzer Launched First Light from an ExPl.
Water Kepler Launched Ozone 2010 Absorb. First Spectrum of a Super-Earth Absorb.
First Earth-sized ExPl Found PlanetBrightness Methane First Habitable Earth-sized ExPl ? Absorb. Carbon Diox. Absorb. JWST Planned Launch 2020 First Spectrum of a Habitable M-Earth? 6 8 10 12 14 Wavelength (μm) Robinson et al. 2011 Bacteria Plants & Algae
2030 N. Gen. Telescope Launched? First Spectrum of a Habitable Earth? Liquid Water