RAADSELS VAN DE STERRENKUNDE Ronald Westra Dep. Mathematics Maastricht University February 2, 2006

Introduction to Astrophysics

lectures : http://www.math.unimaas.nl/personal/ronaldw/home1.htm

IInhoud 1. Geschiedenis en schalen 2. Zon en het Zonnestelsel   1. Geschiedenis en schalen 2. Zon en het Zonnestelsel 3. Evolutie van sterren 4. Melkwegstelsels 5. Grootschalige strukturen en dynamica 6. Kosmologie en Antigravity

IInhoud College 1: Schalen in ruimte en tijd   Schalen in ruimte en tijd Geschiedenis van de astronomie De natuur van het licht Optica en telescopen

Astronomic Scales in Space and Time 1. Astronomic Scales in Space and Time

Earth Sun Jupiter.

http://micro.magnet.fsu.edu/primer/java/scienceopticsu/powersof10/

Galaxy M31, known as the Andromeda nebula

Collection of galaxies Collection of galaxies. The three fuzzy galaxies left merging, The crisp galaxy in the center is on the background

Large-scale map of the observable universe showing the the largest structures visible in the universe. Each point in this diagram represents one single galaxy

The Universe at the young age of 300,000 years The Universe at the young age of 300,000 years. The colors represent temperature fluctuations in the Cosmic Background Radiation Wilkinson Microwave Anisotropy Probe

Subtle variations in the CBR.

The Giant Impact Theory suggests that a Mars-sized object crashed into the early Earth. Most of the debris thrown into space fell back on Earth, but a fraction aggregated into the Moon. This theory is supported by the similar composition of rocks on the Earth and Moon.

Geschiedenis van de astronomie

History of astronomy Ancient history Hindu Astronomy Mesopotamia / Sumer / Chaldea, Babylonia Mesoamerica China Ancient Greece Middle Ages

Nicolaus Copernicus (1473-1543) The Copernican heliocentric system

The Ptolomaic heliocentric system

The Ptolomaic heliocentric system

Nicolaus Copernicus De revolutionibus orbium coelestium

Nicolaus Copernicus (1473-1543)

Galileo Galilei (1564-1642)

Johannes Kepler (1571-1630)

Tyho Brahe (1546-1601)

Johannes Kepler

Johannes Kepler

Kepler's elliptical orbit law: Johannes Kepler Kepler's elliptical orbit law: The planets orbit the sun in elliptical orbits with the sun at one focus. 2. Kepler's equal-area law: The line connecting a planet to the sun sweeps out equal areas in equal amounts of time. 3. Kepler's law of periods: The time required for a planet to orbit the sun, called its period, is proportional to the long axis of the ellipse raised to the 3/2 power. The constant of proportionality is the same for all the planets.

Isaac Newton (1642-1727)  

Voorbeeld: zwaartekracht Observaties aan bv planeetbanen Experimenten met bv valbewegingen en slingers (Mathematische) Theorie

Newton zet de standaard   T * Absolute ruimte en tijd * afgeleide grootheden: snelheid, versnelling, impuls ·   * abstractie van een puntmassa * abstracte grootheden: kracht, energie ·             * abstracte grootheden: kracht hangt van positie af *

Newton zet de standaard   T * De natuurwet als principe: [1] de ratio van de verandering van de impuls van een puntmassa is gelijk aan de resulterende kracht die op de puntmassa werkt

Newton zet de standaard   T * De natuurwet als principe: [2] de zwaartekracht op een bepaalde plek h de ratio van de verandering van de impuls is gelijk aan de kracht van een massa van M kilo op een puntmassa op is omgekeerd evenredig met het kwadraat van de afstand r van zijn centrum

VVolgens Newton T tijd t plaats x impuls p kracht F  

VVolgens Newton T

Optica en telescopen

Physics of Light

Physics of Light

Solar absorption spectrum

Optica en telescopen

Optica en telescopen (Newton’s oorspronkelijke telescoop)

Optica en telescopen

Optica en telescopen

Optica en telescopen

Optica en telescopen

Optica en telescopen Hubble Space Telescope

Optica en telescopen X-ray astronomy moon

Hubble Space Telescope

Hubble Space Telescope

Hubble Space Telescope

http://cassfos02.ucsd.edu/public/astroed.html#TUTORIAL

The End

Appendix van deel 1

2. Stellar Evolution

Some characteristics of the sun radius (R) 7 1010 cm mass (M) 2 1033 g mean density () 1.4 g/cm3 total energy output (L) 3.82.1026 Joule/sec age 1.5 1017 sec core temperature 5 106 K surface temperature 5 103 K distance to earth 1.5 1013 cm

Nuclear fusion in centre of sun

Spectral Types O – B – A – F – G – K – M – R – N – S

Absolute and Relative Luminosity

Original Hertzsprung-Russell Diagram ( HRD)

Binding energy per nucleon as function of mass number A.

Glowing gaseous streamers of an extinct titanic supernova explosion of a massive star in Cassiopeia A (Cas A)

Composite image of the Crab Nebula showing superimposed images of X-ray (blue) (by Chandra X-ray space telescope), and optical (red) (by the Hubble space telescope).

First published registration of a pulsar, Hewish et al., Nature 217, p. 710, 1968.

Path of the stellar evolution of a main sequence star of one solar mass in the Hertzsprung-Russell diagram log Teff in K log L/ L

sun L/ L surface temperature (K) The HRD for 10 stellar clusters. At right ordinate the age in billion years of the bifurcation point from the main sequence.

Abundances of chemical elements in the neighbourhood of our sun Abundances of chemical elements in the neighbourhood of our sun. The marks are from the intensities from spectral absorption lines in the sun’s atmosphere, the lines from meteorite and terrestrial data.

An example of an unstable – but not-periodic – star is this massive ‘Wolf-Rayet star’ NGC2359, that irregularly ejects large parts of its own outer envelope in gargantuan explosions. The star itself is in the central bubble, the clouds are remnants of previous ejections.

main sequence Luminosity surface temperature RR Lyrae Cepheids instability strip surface temperature Luminosity Variable stars in the HRD. Pulsating variable stars are found in the instability strip connecting the main sequence and the red-giant region. long period variables

Relation between luminosity and oscillation period for Cepheid type 1 variable stars.