Solar System Formation 4. Outer material accretes to form planetesimals 1. Rotating cloud of gas & dust 2. Cloud spins & flattens, forms a disk 3. Core of disk forms young star solar nebula

Our Solar System Types of planets depend on: - temperature - amount of material rocky planets (Terrestrial) gas planets (Jovian) Rocky planets formed closer to Sun Gas giants formed further out STANDARD MODEL

Constellation Orion Stellar Nurseries Example: Orion Nebula Hubble birthplace of new stars, new solar systems?

high eccentricity (more oval) low eccentricity (more circular) Vocabulary Extra Solar Planet (ESP): a planet around a star other than our Sun ESP brown dwarf: less mass than a star, more mass than Jupiter light year: distance light travels in 1yr eccentricity: how elliptical an orbit is kg kg kg

Planet Quest

The First Searches 1920s - Edwin Hubble: identified neighboring galaxies 1980s - B. Smith & R. Terrile: captured 1st image of debris disk around star Hubble outside galaxy Beta Pictoris dust disk

Discovery At Last 1995: Michel Mayor & Didier Queloz (Swiss) - 1st ESP orbiting star 51 Pegasus 1995: Geoff Marcy & Paul Butler (SF State, UC Berkeley) - confirmed discovery - found many more 2000’s: dozens more by 2006: 193 planets 14 multiple planet systems and many more now… Mayor & Marcy 51 Peg ESP & 51 Peg

Star GQ Lupi & planet planet GQ Lupi

Tau Bootis 16 Cygni B 55 Cancri 47 Ursae Majoris 70 Virginis

Extra Solar Planets Distance from parent star (AU) M JUP = mass of Jupiter 1 2 Stars

Characteristics of ESPs Jupiter-sized and bigger Orbit close to star (closer than Mercury) “Hot Jupiters” Eccentric orbits Orbit close to star Orbits highly eccentric

Detection Obstacles - Too far away - Don’t produce any of own light - Lost in glare of parent star Solution: look for effects on parent star

Methods of Detection Doppler Shift plus others…… Transit Method Direct Detection

Doppler Shift & Orbit Wobble Star and planet orbit center of mass Tug of gravity causes star to wobble Planet has small gravitational affect on star X X X = center of mass gravity

Review: Light Waves BIGGER wavelengths smaller wavelengths

Red ‘Shift’ vs. Blue ‘Shift’ waves appear compressed light moving toward observerlight moving away from observer waves appear stretched observer of star RED SHIFTBLUE SHIFT DOPPLER SHIFT

Detection: Doppler Shift Planet causes star to wobble in circular orbit moving toward observer moving away from observer Light from star is Doppler shifted

Detection: Doppler Shift

Wobbles from Neptune-sized planet orbiting star Gliese 436 Real Star Wobbles Star moving toward Star moving away Gliese 436

Detection: Transit Method planet passes between star and observer planet blocks out tiny portion of star’s light star’s light appears to dim

Detection: Transit Method planet passes between star and observer planet blocks out tiny portion of star’s light star’s light appears to dim

Direct Detection Giant planet and young brown dwarf state-of-art infrared images detect light light years away

Future Missions 2001: Keck Interferometer 2011: Space Interferometry Mission (SIM) Planet Quest 2014: Terrestrial Planet Finder Keck Interferometer SIM Planet Quest Terrestrial Planet Finder - began capturing 1st images of gas giant EPSs - will detect evidence for earth-sized planets - will send back 1st pictures of nearby planetary systems

What is your favorite planetary body? Give one scientific reason why.