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A Turtorial Lecture on Exoplanets Wing-Huen Ip Institutes of Astronomy and Space Science National Central University August 31, 2012 Introduction Planets before 1995… small rocky planets close to the Sun gas-giant planets more distant from the star You are here! Discovery of the first exoplanet: Peg 51b in 1995 http://spiff.rit.edu/classes/phys230/lectures/planets/planets.html Periodic Variation of the Spectral Lines http://www.cfa.harvard.edu/afoe/51Peg.html http://lcogt.net/spacebook/radial-velocity-method Doppler Effect http://mail.colonial.net/~hkaiter/Doppler_Effect_Shift.html Red Shift Effect and Hubble Constant http://www.answersingenesis.org/articles/tba/universe-confirms-bible http://astronomy21st.blogspot.tw/2010/03/universe-expansion-is-speeding-up.html Mass vs semi-major axis http://jila.colorado.edu/~pja/planets/extrasolar.html A new class of planets: Super-Earths! GJ1214 Neptune/GJ436 Earth Kepler 10b CoRoT-7b 11 55 Cnc e Mp sin I Effect Sin i : large Mayor & Queloz, 1995 Sin i : small Exoplanet Transit http://www.astro.caltech.edu/people/faculty/wasp10_transit_600.jpg -What are these planets actually like? (atmospheric composition? thermal properties?) - Why are they as they are? Habitable Zone https://www.e-education.psu.edu/astro801/content/l12_p4.html There is more to mass and radius… The Hot Jupiters Orbital distribution Thermal evaporation of the atmosphere of hot Jupiters http://star.herts.ac.uk/RoPACS/JoGo.html WASP-12b Space Weather The Hot Jupiters • Tidal interaction and/or electromagnetic effects (Cuntz and Shkolnik, 2002)? • Superflares from star-planet interaction )Rubenstein and Schaefer (2000)? Star-planet Magnetic Interaction Three Types of Magnetic Coupling Power = VB2L2 ergs/s ~ 1027 ergs/s Ip, Kopp and Hu (2004) Magnetospheric Substorms Observational Test • Detection of excessive Ca II H and K line emissionsynchronized to orbital period of the Hot Jupiter ( Skholnik et al. 2005) • On/off nature of such hot spots (Skholnik et al., 2008) Kepler Observations • Maehara et al. (2012): Superflares on solar-type stars • 9751 sola-type stars in Kepler field • 365 superflares (>1035 ergs) in 148 stars Kepler Observations • Maehara et al. (2012): Superflares on solar-type stars • 9751 sola-type stars in Kepler field • 365 superflares (>1035 ergs) in 148 stars • None of them has Hot Jupiter! Sun spots and star spots http://go.owu.edu/~physics/StudentResearch/2003/BethCademartori/index.html Kepler Observations • Maehara et al. (2012): Superflares on solar-type stars • 9751 sola-type stars in Kepler field • 365 superflares (>1035 ergs) in 148 stars • One million times stronger than the biggest solar flares ever obeserved. • Frequency is about once every 5000 years • None of them has Hot Jupiter! Could Superflares happen on the Sun? Space weather http://www.eee.metu.edu.tr/~etulunay/ytulunay/ Electricity black out on March 13, 1989 Electricity blackout of August 14, 2003, in New York Electricity blackout in July, 2012 Search for Earth-like Habitable Exoplanets by the Kepler Mission: New Results from IAU GA, Beijing (20-31, 8, 2012) The Kepler Mission • The scientific objective of Kepler is to explore the structure and diversity of planetary systems.[45] This spacecraft observes a large sample of stars to achieve several key goals: • To determine how many Earth-size and larger planets there are in or near the habitable zone (often called "Goldilocks planets")[46] of a wide variety of spectral types of stars. • To determine the range of size and shape of the orbits of these planets. • To estimate how many planets there are in multiple-star systems. • To determine the range of orbit size, brightness, size, mass and density of short-period giant planets. • To identify additional members of each discovered planetary system using other techniques. • Determine the properties of those stars that harbor planetary systems. Kepler FOV 115 sq. deg. Planetary candidates observed by Kepler III. Analysis of the first 16 months of data • Batalha, N. et al. • arXiv:1202.5852, 2012 Kepler-20: A sun-like star with threesub-Naptune exoplanets and two Earth-size candidates • Gautier, T.N., et al. • ApJ, 749, 15, 1, 2012 Two Earth-sized planets orbiting Kepler-20 • Fressin, F. et al. • Nature, 482, 195, 2012 Kepler-20e and 20f Kepler-20 (also designated as KOI 070, KIC 6850504 and 2MASS J19104752+4220194) is a G8V star of Kepler magnitude 12.497 and celestial coordinates right ascension α = 19 h 10 min 47.5 s and declination δ = +42° 20′ 19.38′′. The stellar properties are listed in Table 1. The photometric data used for this work were gathered between 13 May 2009 and 14 March 2011 (quarter 1 to quarter 8), and comprise 29,595 measurements at a cadence of 29.426 min (black dots). The Kepler photometry phase-binned in 30-min intervals (blue dots with 1σ standard error of the mean (s.e.m.) error bars) for Kepler-20 e (a) and Kepler-20 f (b) is displayed as a function of time, with the data detrended4 and phase-folded at the period of the two transits. Transit models (red curves) smoothed to the 29.426-min cadence are overplotted. These two signals are unambiguously detected in each of the eight quarters of Kepler data, and have respective signal-tonoise ratios of 23.6 and 18.5, which cannot be due to stellar variability, data treatment or aliases from the other transit signals4. Keplere-20e and 20f Kepler-20 e and Kepler-20 f theoretical mass and observed radius ranges (1σ) are plotted as orange- and green-shaded areas, while the other transiting planets with dynamically determined masses are plotted in black, with 1σ error bars. The curves are theoretical constant-temperature mass– radius relations27. The solid lines are homogeneous compositions: water ice (solid blue), MgSiO3 perovskite (solid red), and iron (magenta). The non-solid lines are mass–radius relations for differentiated planets: 75% water ice, 22% silicate shell and 3% iron core (dashed blue); Ganymede-like with 45% water ice, 48.5% silicate shell and 6.5% iron core (dot-dashed blue); 25% water ice, 52.5% silicate shell and 22.5% iron core (dotted blue); approximately Earth-like with 67.5% silicate mantle and 32.5% iron core (dashed red); and Mercury-like with 30% silicate mantle and 70% iron core (dotted red). The dashed magenta curve corresponds to the density limit from a formation model24. The minimum density for Kepler-20 e corresponds to a 100% silicate composition, because this highly irradiated small planet could not keep a water reservoir. The minimum density for Kepler-20 f follows the 75% water-ice composition, representative of the maximum water content of comet-like mix of primordial material in our Solar System28. Architecture and dynamics of Kepler’s candidate multiple transiting planet system • Lissauer, J., et al. • ApJ Suppl. Series, 197, 1, 2011 Systems of 4-6 Planets Kepler-47b and c: A planetary system orbiting around a binary star (8/29/2012) NASA's Kepler Discovers Multiple Planets Orbiting a Pair of Stars Published by Klaus Schmidt on Wed Aug 29, 2012 12:37 pm via: NASA Share More share options Tools Suggest NewsReport Article Add CommentPrint Article Tags NASA, Kepler, Exoplanets, Kepler-47c, Kepler-47b MOFFETT FIELD, Calif. — NASA’s Kepler mission has discovered multiple transiting planets orbiting two suns for the first time. The system, known as a circumbinary planetary system, is 4,900 light-years from Earth in the constellation Cygnus. Coming less than a year after the announcement of the first circumbinary planet, Kepler-16b, this discovery proves that more than one planet can form and persist in the stressful realm of a binary star. The discovery demonstrates the diversity of planetary systems in our galaxy. NASA Press Conference at IAU at Beijing on August 29, 2012 by Dr. Natalie Batalha and Prof. William Welsh Star War! http://articles.businessinsider.com/2011-09-27/home/30207350_1_kepler-spacecraft-telescopes-european-southernobservatory Prof. Chung-Ming Ko on ET Thank You!