Kepler Mission:

The Search Earth-like Planets

By Kurt Wiehenstroer

May 9, 2007

Planet Finding History

Mercury 3000 BC

Venus, Mars, Jupiter, Saturn “Wondering stars”

1610 Galileo - telescopic Jupiter

Uranus, William Herschel March 13, 1781

Neptune was first observed by Galle and d'Arrest on Sept 23, 1846

Dwarf Planet Pluto was discovered in 1930 by a fortunate accident. Clyde W. Tombaugh.

Around PSR B1257+12 1991-92 Aleksander Wolszczan

Doppler Shift due to Stellar Wobble

Most successful Method

larger the planet - more the wobble

closer to the star - more the wobble

The larger color shift in the spectrum of starlight.

Its light is red shifted

Light is blue shifted

Longer

wavelength

Shorter waveleng

th

Toward us - blue-shifted

Away - red-shifted

Radial Velocity

Radial Velocity

Best spectroscopes detect motions of about 15 meters/sec

Earth only forces the Sun to move at 0.1 meters/sec

orbit and mass

Radial velocity 51 Pegasi

Astrometric Method

Slight side to side motion of the star caused by the orbiting planet (RA & DEC).

Peter van de Kampf tried to confirm exoplanets orbiting Barnard's star using this method in 1982.

NASA's SIM PlanetQuest mission and the Keck Interferometer I & II (Hawaii) will use this strategy.

Sun due to Jupiterat 33 light years

Transit TechniqueFirst demonstrated in 1999 on an extrasolar planet

An Eclipse: A distant planet moves between us and its star slight decrease in brightness.

Kepler mission

launch 2008

Secondary Eclipse Technique

Star 10,000 or more x brighter than the planet - visible

Planets give off infrared = heat

Star only 100’s x brighter in infrared

Star + Planet = Infrared

Planet goes behind star, IR of star only

Subtract the two = IR of planet

Light rays become bent when passing through space that is warped by the presence of a massive object such as a star.

Gravitational microlensing find objects that emit no light or are otherwise undetectable.

Direct imaging

Detect the planets themselves.

Block out some of the light from the star

Take direct photos

Technique - starlight nulling.

173 light years, 5J mass, orbit 1700 years around brown dwarf, constellation Hydra

Other methods

Polarimetry - polarizied light

Star light 'unpolarised', planet light 'polarised'

Polarimeters detect polarised light

Nulling Interferometry -

Pulsar Timinglighthouse lightpulses timing altered

Johannes Kepler

German mathematician

Astronomer and astrologer

Key figure in the 17th century astronomical revolution.

Most known for three laws of planetary motion

still used today

(December 27, 1571 – November 15, 1630)

1. Elliptical orbits2. Law of Equal Areas - change velocity 3. Time of orbit & distance from Sun

Kepler Mission

A NASA Discovery mission selected in 2001

Spaceborne telescope - survey distant stars

Determine the prevalence of Earthlike planets.

Detect planets indirectly, uses the "transit" method.

Kepler Telescope

Kepler Telescope37” mirror

FAQsWhy can't Earth-size planetary transits be

observed from the ground?

The atmosphere

Don't the stars vary more than the change caused by a transit?

The transit will cause more change than the stars like our sun change.

Why not use the Hubble Space Telescope?

The field of view (FOV) of the HST is too small to observe a large number of bright stars.

Are there other photometry missions?

MOST and COROT.

Visible Stars with Planets0. Pollux Gemini 1.0 1.6 590 day

Visible Starts with Planets

Canada's First space Telescope

MOST ~ Microvariabilite & Oscillations Stellaires

June 30, 2003 low-Earth Polar orbit 820 km high/ 100 mins

Suitcase-sized microsatellite

(65 x 65 x 30 cm; 60kg)

Optical mirror - 15 cm

CCD (1024 by 1024 pixels)

Photometry Method

COROT (French)

COnvection ROtation and planetary Transits.

Polar orbit, 827km high, December 27, 2006

Launch vehicle: Soyuz 2.1b 630kg

Mirror: 27cm afocal, 2½ year mission

Detectors: 4 CCD's 2048 x 2048 wide

COROT finds May 2007 COROT first planet , ‘COROT-Exo-1b’, Very hot gas giant, with a radius = 1.78 x

Jupiter. Orbits a yellow dwarf star similar to Sun, period

of about 1.5 days. 1500 light years from us, in the direction of the

constellation Unicorn (Monoceros). Coordinated spectroscopic observations from

the ground equivalent to about 1.3 of Jupiter.

If approved and built, launch in 2014 or

later.

Infra-red telescope absorption lines water,

carbon dioxide and

ozone

Infra-Red Space

Interferometer

ESA’s Darwin Mission

SIM PlanetQuestSIM PlanetQuest launch in 2015 JPL

Positions and distances of stars several hundred times more accurate than any previous program.

Optical interferometry - light from two

or more telescopes

combined to = single, gigantic

telescope mirror

Terrestrial Planet Finder (TPF) Two complementary observatories ~visible, infrared

Size, temperature, and placement of planets

Earth-sized in the habitable zones of distant solar systems.

Spectroscopy - life gases like carbon dioxide, water vapor, ozone and methane

Visible Infrared

The James Webb Space Telescope

The James Webb Space Telescope (JWST) is a large, infrared-optimized space telescope, scheduled for launch in 2013. JWST's instruments will be designed to work primarily in the infrared range of the electromagnetic spectrum, with some capability in the visible range.

JWST will have a large mirror, 6.5 meters (21.3 feet) in diameter and a sunshield the size of a tennis court. JWST will reside in an orbit about 1.5 million km (1 million miles) from the Earth.

James Webb Space TelescopeNorthrop Grumman Space Technology

Gliese 581 cApril 2007

Mass(m)> 5.03 ME Radius(r)~1.5 RE Density(ρ)> 8191.45 kg/m3 Temperature(T)~290 K 26.6 F Age ~ 4.3 Billion years Orbital period(P) 12.93 d Found using radial velocity technique

4/26/2007Gliese 581 system as rendered in

Celestia

Linkshttp://www.nineplanets.org/

http://library.thinkquest.org/03oct/01858/text-only/aboutmars_history.html

http://planetquest.jpl.nasa.gov/science/finding_planets.cfm

http://filer.case.edu/sjr16/esol_find.html

http://www.star.le.ac.uk/edu/Extrasolar.shtml

http://www.geocities.com/jilljade/astro/extrasolar.html

http://www.spitzer.caltech.edu/Media/factsheets/050312_planethunt.shtml

http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=29484

http://www.hinduonnet.com/fline/fl2303/stories/20060224003010300.htm

http://en.wikipedia.org/wiki/Hubble_Space_Telescope

http://en.wikipedia.org/wiki/James_Webb_Space_Telescope

http://en.wikipedia.org/wiki/Methods_of_detecting_extrasolar_planets

http://www.esa.int/SPECIALS/COROT/SEMCKNU681F_0.html

More linkshttp://www.eso.org/outreach/eduoff/edu-prog/catchastar/CAS2004/casreports-

2004/rep-226/

http://www.nasa.gov/vision/universe/starsgalaxies/betapicMM.html

http://shayol.bartol.udel.edu/~rhdt/diploma/lecture_10/

http://www.st.northropgrumman.com/media/SiteFiles/mediagallery/video/jwst_model.jpg

http://en.wikipedia.org/wiki/Johannes_Kepler

http://kepler.nasa.gov/

http://www.astro.ubc.ca/MOST/overview.html

http://en.wikipedia.org/wiki/COROT

http://smsc.cnes.fr/COROT/

http://www.esa.int/esaSC/SEMYZF9YFDD_index_0.html

http://en.wikipedia.org/wiki/2M1207b

http://en.wikipedia.org/wiki/2M1207

http://en.wikipedia.org/wiki/Extrasolar_planet

http://en.wikipedia.org/wiki/Gliese_581_c