A Census of the Solar System

1 star and 8 major planets Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune terrestrial giant (1) (2) (39) (18) (23) (8)

Planetary comparisons The Gas Giants Jupiter -- 1/1000 M sun, 300 M earth 1/10 R sun, 11 R earth

Terrestrial Objects 7 largest moons

Other members Dwarf Planets – Pluto and the Trans-Neptunian or Kuiper Belt Objects

Highly elliptical orbit inclined 17 0 to ecliptic Brings it inside Neptune’s orbit, 1979 – 1999, Pluto was closer than Neptune

Asteroids, Meteors and Comets

Fundamental Properties of the solar System 1. Planets and their satellites all lie in the same plane - the ecliptic – to within a few degrees 2. Sun’s rotational equator aligned with ecliptic 3. Planetary orbits are nearly circular ellipses 4. Planets all revolve in same W -> E direction 5. Sun and planets all rotate on axes in same W –E direction (except Venus and Uranus) 6. Distance between planets have a regular spacing (Bode’s Law) 7. Planet – satellite systems resemble solar systems 8. comets define a large almost spherical cloud surrounding the solar system – Oort Cloud 9. Planet compositions differ and there is a gradient with distance from the Sun 10. All mass is in the Sun (99.9%) but most of the angular momentum is in the planets

Formation of Solar System

The Condensation Sequence of the elements, minerals and molecules

The Heavy Bombardment

Astrometric Detection Method Doppler Detection Method Transit Detection Method The first two methods are based on the fact that a planet orbiting a star will cause the star to "wobble" in space. The first method detects the component of this wobble that is horizontal to our line of site, and is based simply on observing the position of the star over time. The Search for ExoSolar Planets

***The second method detects the component of the wobble that is radial to us, (i.e. directly towards or away from us), and is based on the Doppler shift in the star's light as the star moves towards or away from us.

*** The third method is based on detecting the small drop in apparent luminosity of a star as a planet transits in front of it, between the star and the Earth.

ExtraSolar System Planets

Multiple systems As of Sept, planets confirmed (JPL) candidates

The Kepler Mission Designed to constantly survey the same region of sky 10 5 sg deg 1.4 meter diameter mirror with a 0.95m photometer. Uses the transit method and survey thousands of stars repeatedly at least 3 – 4 times to determine period and orbit of transiting planet.

A NASA telescope taking a nose count of planets in one small neighborhood of the Milky Way registered more than 1,200 candidates, including 58 residing in life-friendly orbits around their parent stars. The census, collected by NASA's Kepler Space Telescope after just four months of work, shows that small planets like Earth are much more prevalent than Jupiter-sized worlds and that multiple-planet systems are common (about 200). Results from Kepler satellite: Press release Feb 2, 2011 As of Sept confirmed, candidates Of these, 21 are in less than twice Earth size and in the habitable zone,

11 new systems with 26 planets

Kepler-22b: A 2.4 Earth-radius Planet in the Habitable Zone of a Sun- like Star Dec 5, 2011 Probably about mass of Neptune ~ 35M earths

Exo planet types

First Earth-sized planet in the habitable zone of another star, April 2014

Finding Habitable Worlds Adaptive Optics – Interferometry – The Large Binocular Telescope

ESO Discovers Earth-Size Planet in Habitable Zone of Nearest Star The new planet circles Proxima Centauri, the smallest member of a triple star system known to science fiction fans everywhere as Alpha Centauri. Just over 4 light- years away, Proxima is the closest star to Earth, besides our own sun. They determined that the new planet, dubbed Proxima b, is at least 1.3 times the mass of Earth. It orbits its star far more closely than Mercury orbits our sun, taking only 11 days to complete a single orbit -- a "year" on Proxima b.

Web sites -- exoplanet.eu exoplanets.org (Caltech) Kepler mission --