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Astronomy 101 The Solar System Tuesday, Thursday 2:30-3:45 pm Hasbrouck 20 Tom Burbine [email protected] HoursHomeworkAstronomy InformationFinalHW #10HW #11If you want to find life outside our solar systemExtrasolar PlanetsStar NamesStar Names nowOur Solar System has basically two types of planetsThings to RememberQuestion:What is the problem when looking for planets?Slide 17Slide 18Slide 19So what characteristics of the planets may allow you to “see” the planetSlide 21Slide 22Slide 23Slide 24Slide 25Some Possible Ways to detect PlanetsPulsarsSlide 28Slide 29Would you want to live on a pulsar planet?Center of MassRadial Velocity (Doppler Method)Slide 33Slide 34Slide 35BiasSlide 37Transit MethodSlide 39One major problemEclipseSlide 42Direct ObservationSlide 44Slide 45Slide 46How did these Hot Jupiters get orbits so close to their stars?Slide 48Kepler MissionSlide 50Slide 51Slide 52Slide 53Slide 54What Planet do we know the most about?Slide 56Slide 57Earth’s InteriorSlide 59Earth’s crustEarth is made of mineralsMineralOlivinePyroxenesHow do we know what’s in the interior of the Earth?Slide 66Seismic WavesSlide 68Surface WavesSlide 70Slide 71Slide 72Slide 73Slide 74Slide 75Slide 76Richter ScaleSlide 78Slide 79Slide 80How do we get information?Which of these bodies have they used seismic waves to study?Slide 83How can you study the interior of a planet from space?DensityGravityMagnetic FieldSlide 88Earth’s magnetic field is believed to be caused by the convection of molten iron, within the outer liquid core along with the rotation of the planetSlide 90Slide 91Slide 92North Magnetic PoleSlide 94Geomagnetic ReversalsSlide 96What may happen during the reversal?Van Allen BeltsSlide 99Slide 100Slide 101James Van AllenAurorasAny Questions?Astronomy 101The Solar SystemTuesday, Thursday2:30-3:45 pmHasbrouck 20Tom [email protected]•Course Website:–http://blogs.umass.edu/astron101-tburbine/•Textbook:–Pathways to Astronomy (2nd Edition) by Stephen Schneider and Thomas Arny.•You also will need a calculator.Office Hours•Mine•Tuesday, Thursday - 1:15-2:15pm•Lederle Graduate Research Tower C 632•Neil•Tuesday, Thursday - 11 am-noon •Lederle Graduate Research Tower B 619-OHomework•We will use Spark•https://spark.oit.umass.edu/webct/logonDisplay.dowebct•Homework will be due approximately twice a weekAstronomy Information•Astronomy Help Desk•Mon-Thurs 7-9pm•Hasbrouck 205•The Observatory should be open on clear Thursdays •Students should check the observatory website at: http://www.astro.umass.edu/~orchardhill for updated information•There's a map to the observatory on the website.Final•Monday - 12/14 •4:00 pm•Hasbrouck 20HW #10•Due todayHW #11•Next TuesdayIf you want to find life outside our solar system•You need to find planets•http://exoplanet.euExtrasolar Planets•Today, there are over 400 known extrasolar planetsStar Names•A few hundred have names from ancient times•Betelgeuse, Algol, etc.•Another system:•A star gets name depending on what constellation it is in•With a Greek letter at the beginning–Alpha Andromeda, Beta Andromeda, etc.•Only works for 24 brightest starStar Names now•Stars are usually named after the catalog they were first listed in•HD209458 is listed in the Henry Draper (HD) Catalog and is number 209458•HD209458a is the star•HD209458b is the first objects discovered orbiting the starOur Solar System has basically two types of planets•Small terrestrial planets – Made of Oxygen, Silicon, etc.•Large gaseous giants – Made primarily of hydrogen and a little helium–Jupiter - 90% Hydrogen, 10% Helium–Saturn – 96% Hydrogen, 3% Helium–Uranus – 83% Hydrogen, 15% Helium–Neptune – 80% Hydrogen, 20% HeliumThings to Remember• The Milky Way has at least 200 billion other stars and maybe as many as 400 billion stars•Jupiter’s mass is 318 times than the mass of the EarthQuestion:•How many of these stars have planets?What is the problem when looking for planets?What is the problem when looking for planets?•The stars they orbit are much, much brighter than the planets•Infrared image of the star GQ Lupi (A) orbited by a planet (b) at a distance of approximately 20 times the distance between Jupiter and our Sun. •GQ Lupi is 400 light years from our Solar System and the star itself has approximately 70% of our Sun's mass. •Planet is estimated to be between 1 and 42 times the mass of Jupiter. •http://en.wikipedia.org/wiki/Image:GQ_Lupi.jpgSo what characteristics of the planets may allow you to “see” the planetSo what characteristics of the planets may allow you to “see” the planet•Planets have mass•Planets have a diameter•Planets orbit the starhttp://upload.wikimedia.org/wikipedia/commons/d/de/Extrasolar_Planets_2004-08-31.png•Jupiter –H, He–5.2 AU from Sun–Cloud top temperatures of ~130 K–Density of 1.33 g/cm3•Hot Jupiters –H, He–As close as 0.03 AU to a star–Cloud top temperatures of ~1,300 K–Radius up to 1.3 Jupiter radii–Mass from 0.2 to 2 Jupiter masses–Average density as low as 0.3 g/cm3100 1,00010(lightyears)Some Possible Ways to detect Planets•Pulsar Timing•Radial Velocity (Doppler Method)•Transit Method•Direct ObservationPulsars•Rotating Neutron Stars•Have densities of 8×1013 to 2×1015 g/cm³•http://www-learning.berkeley.edu/astrobiology/powerpointhtml/sld035.htm•http://en.wikipedia.org/wiki/Image:Ssc2006-10c.jpgWould you want to live on a pulsar planet?Center of Mass•Distance from center of first body = distance between the bodies*[m2/(m1+m2)]•http://en.wikipedia.org/wiki/Doppler_spectroscopyRadial Velocity (Doppler Method)http://www.psi.edu/~esquerdo/asp/shifts.jpg•http://astronautica.com/detect.htmhttp://www.psi.edu/~esquerdo/asp/method.htmlWavelengthwww.physics.brandeis.edu/powerpoint/Charbonneau.pptBias•Why will the Doppler method will preferentially discover large planets close to the Star?Bias•Why will the Doppler method will preferentially discover large planets close to the Star?•The gravitational force will be higher•Larger Doppler ShiftTransit Method•When one celestial body appears to move across the face of another celestial body•When the planet crosses the star's disk, the visual brightness of the star drops a small amount •The amount the star dims depends on its size and the size of the planet. •For example, in the case of HD
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