Are There Other SOLAR SYSTEMS? Searching for EXO-PLANETS Techniques & Technologies

Program assembled by Rick Kang from Eugene Education/Public Outreach Coordinator – Oregon Astrophysics Outreach Education/Public Outreach Coordinator – Oregon Astrophysics Outreach Tourguide – U of O’s Tourguide – U of O’s Pine Mountain Observatory Pine Mountain Observatory

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What is an EXO-PLANET?

A Planet that ORBITS another Star/Sun A Planet that ORBITS another Star/Sun Very far away Very far away May or may not be like Earth May or may not be like Earth

Everyone understand difference between Solar System and Galaxy? Solar System is tiny part of Galaxy.

Hundreds of BILLIONS of STARS in a GALAXY HOW MANY STARS HAVE PLANETS??? HOW MANY STARS HAVE PLANETS??? WE’RE JUST BEGINNING TO FIND OUT! WE’RE JUST BEGINNING TO FIND OUT!

Why are Exo-Planets of interest?

 Potential location of other life forms/creatures!  Potential location for us to migrate to eventually  Clues about formation of our Solar System/Planet  General interest/travel and exploration destination  Possible source of natural resources

Actual Exo-Planets directly IMAGED so far Star name – number of planets Star name – number of planets Distance from Solar System Distance from Solar System Fomalhaut – 1 planet Fomalhaut – 1 planet 25 light years 25 light years Beta Pictoris – 1 planet Beta Pictoris – 1 planet 63 light years 63 light years HD8799 – 4 planets HD8799 – 4 planets 140 light years 140 light years

4 th planet found

Why is Direct Imaging difficult to do?

DISTANCE!!! DISTANCE!!! Stars are tiny dots Stars are tiny dots Planets are very tiny dim dots Planets are very tiny dim dots Separation is very slim Separation is very slim BRIGHTNESS of STAR overwhelms light of Planet. BRIGHTNESS of STAR overwhelms light of Planet. Planet may take many years to orbit star, to show motion. Planet may take many years to orbit star, to show motion.

How do we select stars to image?

Stars with DUST DISKS! Stars with DUST DISKS! Radiate infrared light (dust) Radiate infrared light (dust) Planets appear to be made from the material in disk around star. Planets appear to be made from the material in disk around star.

Proplyd disks around some of Orion’s stars

Disks in radio light around Fomalhaut, Beta Pictoris, Vega – lobes may be planets

INDIRECT ways to detect presence of exo-planet(s)

INDIRECT ways to detect exo-planet(s) Consider a MODEL of a Planet orbiting a Star, seen from VERY FAR AWAY (Star appears as bright dot, Planet is INVISIBLE.) Consider a MODEL of a Planet orbiting a Star, seen from VERY FAR AWAY (Star appears as bright dot, Planet is INVISIBLE.) We have Technologies that detect and measure AMOUNT, We have Technologies that detect and measure AMOUNT, COLOR, and relative POSITION of incoming PHOTONS. COLOR, and relative POSITION of incoming PHOTONS.

Consider a distant Solar System viewed Edge-On… what might you observe?

If there’s a Planet, when it passes in front of its Star… If there’s a Planet, when it passes in front of its Star… Maybe the total LIGHT would DECREASE! A TRANSIT EVENT. Maybe the total LIGHT would DECREASE! A TRANSIT EVENT. An orbiting Planet would create CYCLICAL transit events. An orbiting Planet would create CYCLICAL transit events. We could measure diameter of Planet and possibly composition of its atmosphere! We could measure diameter of Planet and possibly composition of its atmosphere!

When this happens

We PLOT Photometric data like

Transit events let us measure Presence of Planet(s). Presence of Planet(s). Orbital period and diameter Orbital period and diameter Diameter of Planet Diameter of Planet Planet’s Atmospheric COMPOSITION Planet’s Atmospheric COMPOSITION Planet’s Temperature Planet’s Temperature

About 1500 Exo-Planet candidates discovered by Transit method so far, amateurs can do this! Of these, over 1200 were detected by the new KEPLER Telescope and Imaging System. Of these, over 1200 were detected by the new KEPLER Telescope and Imaging System. Kepler Telescope, in Space, searches for Earth-like planets in a Habitable Zone that orbit Sun-like Stars. Basically a statistical search for LIFE. Kepler Telescope, in Space, searches for Earth-like planets in a Habitable Zone that orbit Sun-like Stars. Basically a statistical search for LIFE.

Technologies to COLLECT and DETECT photons TELESCOPES: TELESCOPES: Use large curved mirrors Use large curved mirrors to COLLECT light to COLLECT light Large Surface Area Large Surface Area Curvature focuses light Curvature focuses light DIGITAL CAMERAS (CHARGE COUPLED DEVICES – CCDs) DIGITAL CAMERAS (CHARGE COUPLED DEVICES – CCDs) Create and measure images Create and measure images Detect arrival of each photon Detect arrival of each photon By Photo-Electric Effect – each photon energizes an electron within the grid By Photo-Electric Effect – each photon energizes an electron within the grid The electrons are counted and mapped The electrons are counted and mapped

How does an Orbiting Planet INTERACT with its Star?

How does Orbiting Planet INTERACT with its Star? GRAVITY holds the Planet in Orbit. GRAVITY holds the Planet in Orbit. Any MASS has GRAVITY…the Planet also has GRAVITY… Any MASS has GRAVITY…the Planet also has GRAVITY… How does the Planet’s GRAVITY affect the Star? How does the Planet’s GRAVITY affect the Star? Kinesthetic and Model demos Kinesthetic and Model demos

Where’s the CENTER of GRAVITY of 2 BODIES? Gently try to swing your partner in orbit around you. Gently try to swing your partner in orbit around you. What FORCES do each of you feel? What FORCES do each of you feel? Are both of you forced to move? Are both of you forced to move? Which way are you forced to move? Which way are you forced to move? Is a STAR moved by its orbiting PLANET? Is a STAR moved by its orbiting PLANET?

If the Star is tugged in a small circle by its Planet Maybe we can see the Star move SIDE TO SIDE…NOT! Maybe we can see the Star move SIDE TO SIDE…NOT! Or, maybe we can see the Star move TOWARD US and AWAY FROM US, wobbling back and forth…NOT DIRECTLY…BUT… Or, maybe we can see the Star move TOWARD US and AWAY FROM US, wobbling back and forth…NOT DIRECTLY…BUT…

Let’s consider Light as a WAVE

Energy of light = COLOR

Counting CRESTS and TROUGHS FREQUENCY (count over period of time) tells us the color. FREQUENCY (count over period of time) tells us the color. Lower Frequency (Energy) = REDDER Lower Frequency (Energy) = REDDER Higher Frequency (Energy)= BLUER Higher Frequency (Energy)= BLUER What might cause the FREQUENCY of light from a Star to CHANGE? What might cause the FREQUENCY of light from a Star to CHANGE? (THE COLOR TO SHIFT?) (THE COLOR TO SHIFT?)

What if the Star is moving TOWARD or AWAY from us? Wouldn’t this cause a RED or BLUE SHIFT? Wouldn’t this cause a RED or BLUE SHIFT? This is how we measure RADIAL MOTION of Stars and Galaxies! This is how we measure RADIAL MOTION of Stars and Galaxies!

Actual SPECTRAL SHIFT is measured by noting shift of spectral ABSORPTION lines, not by actually seeing color!

How do we determine if star is moving TOWARD or AWAY from us?

BLUE SHIFT = TOWARD BLUE SHIFT = TOWARD RED SHIFT = AWAY RED SHIFT = AWAY

Doppler Wobble method of detecting exo-planets

Star 51 Pegasi doppler shift

What else does the shift tell us?

Presence of Planet(s) Presence of Planet(s) Orbital period Orbital period Distance from Star Distance from Star Temperature inferred from distance Temperature inferred from distance Mass of Planet Mass of Planet

Summary of TWO METHODS TRANSIT: Look for periodic dimming of overall light from Star. TRANSIT: Look for periodic dimming of overall light from Star. DOPPLER WOBBLE: Look for periodic very slight red-blue shift in spectral lines of light from Star DOPPLER WOBBLE: Look for periodic very slight red-blue shift in spectral lines of light from Star

Other indirect methods? Yes, but not that successful 1. Gravitational lensing (brief brightening) 2. Pulsar timing signal change 3. Proper motion (back and forth wobble) wobble)

Notice BIAS in the Transit and the Doppler Wobble methods: (consider how these are both done, what are we observing: Dimming, and Tugging

BIAS factor: BIG PLANETS are discovered much more often: BIG PLANETS are discovered much more often: more shadow or more gravity! more shadow or more gravity!

Current Count of EXOPLANETS

528 STARS with PLANETS 528 STARS with PLANETS as of as of WE DON’T KNOW HOW MANY PLANETS per STAR WE DON’T KNOW HOW MANY PLANETS per STAR

So, Are There Other Solar Systems? YES! YES! From preponderance of Dust Disks detected, and statistics of numbers of stars that show planet presence by all of the detection methods so far, From preponderance of Dust Disks detected, and statistics of numbers of stars that show planet presence by all of the detection methods so far, PERHAPS MOST STARS HAVE SOLAR SYSTEMS! PERHAPS MOST STARS HAVE SOLAR SYSTEMS!

HOW DOES THIS STATISTIC AFFECT SEARCH FOR LIFE?