A Turtorial Lecture on Exoplanets

Wing-Huen IpInstitutes of Astronomy and Space

ScienceNational Central University

August 31, 2012

Introduction

You are here!

Planets before 1995…small rocky planets close to the Sun

gas-giant planets more distant from the star

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

11

Neptune/GJ436

Kepler 10bCoRoT-7b

GJ1214

Earth

A new class of planets:Super-Earths!

55 Cnc e

Mayor & Queloz, 1995

Sin i : large

Sin i : small

Mp sin I Effect

Exoplanet Transit

http://www.astro.caltech.edu/people/faculty/wasp10_transit_600.jpg

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

Ip, Kopp and Hu (2004)

Power = VB2L2 ergs/s~ 1027 ergs/s

Magnetospheric Substorms

Observational Test• Detection of excessive Ca II H and K line emission-

synchronized 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 three-sub-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-to-noise 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 20fKepler-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 StarsPublished by Klaus Schmidt on Wed Aug 29, 2012 12:37 pm via: NASAShareMore share options

ToolsSuggest NewsReport ArticleAdd CommentPrint ArticleTagsNASA, 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-southern-observatory

Prof. Chung-Ming Ko on ET

Thank You!