Observing the Universe

Transcription

1 Observing the Universe Stars & Galaxies Telescopes

2 Any questions for next Monday?

3

4 Light

5 Doppler effect

6 Doppler shift

7 Doppler shift

8 Spectra Doppler effect

9 Spectra

10 Stars

11 Star and planet formation Sun Low-mass star Brown Dwarf Earth Gravitational collapse of interstellar clouds Diversity of planets (mass, distance to central star, excentricity, chem. comp. etc.): interaction of many processes

12 Stellar evolution Planet evolution linked to stellar evolution Stars evolve through thermonuclear burning Change of chemical composition Typical evolution times: billions of years Solar-like stars (~ 1M ) become Red Giants

13 Stars

14 Hertzsprung-Russell diagram

15 Stars Ages: between 1 million and 10 (to 100) billions of years Chemical composition: 70% H, 28% He, rest heavy elements (and small variations) Diameter: 20 km (neutron star) to km (e.g., Betelgeuze,650 solar radii) Kinematics: parallax and proper motion, Doppler shift and radial velocity Mass: 0, solar masses Temperature (surface): ~3000 up to K Brightness: 0, x Sun s brightness

16 Eta Carinae

17 Hertzsprung-Russell diagram

18 Spectral Class Prism Lines in stellar spectra Chemical elements Absorption Spectrum Which lines are visible depends on the star s temperature

19 Spectral Type Class Temperature Sample star O 33,000 K or more Zeta Ophiuchi B 10,500 30,000 K Rigel A 7,500 10,000 K Altair F 6,000 7,200 K Procyon A G 5,500 6,000 K Sun K 4,000 5,250 K Epsilon Indi M 2,600 3,850 K Proxima Centauri Oh Be A Fine Girl/Guy, Kiss Me!

20 The nearest star

21 InterStellar Medium (ISM) Components: stars, planets, gas, dust, radiation fields, magnetic fields, high-energy particles Chemical evolution of a galaxy through enrichment with heavy elements from the final stages of stellar evolution (SN)

22 Stars & Galaxies Stars group together to form galaxies, and they dominate the visible universe

23 The Milky Way

24 The Milky Way 360-degree photographic panorama of the entire galaxy, from the viewpoint of the solar system

25 NGC 7331 is often referred to as "the Milky Way's twin.

26 Galaxies Gravitationally bound system: to stars, interstellar medium of gas and dust, dark matter

27 Galaxies Whirlpool Galaxy

28 Galaxies Sketch of the Whirlpool Galaxy by Lord Rosse in 1845

29 Galaxies 1920s: Edwin Hubble - Cepheid variables in distant spiral nebulae These objects are far too distant to be part of the Milky Way.

30 Galaxies

31 Galaxies

32 Galaxy Morphology E: Elliptical S: Spiral SB: Barred Spiral Hubble classification scheme

33 Galaxy Morphology Halo of dark matter Dust Bulge Core Spiral arms Envelope M87, E1, Virgo cluster Ulaanbaatar, May 2007, M83, SAB(s)c Astronomy Lecture Series at the National University of Mongolia, Katrien Kolenberg

34 Andromeda: M 31= NGC 224 Spiral galaxy vom Typ Sb Distance: d = 670 kpc Moving towards us! Merging with the Milky Way in about years This may build an elliptical galaxy Radius: 24 kpc Lots of small dwarf galaxies accompanying it, M32 = NGC221 und NGC205

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36 Galaxy Groups and Clusters Seyfert's Sextet: a compact galaxy group

37 The Local Universe Virgo Supercluster

38 Observing Tools: Telescopes

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40 Optical Telescopes * The refracting telescope: lenses * The reflecting telescope: mirrors * The catadioptric telescope: combination of mirrors and lenses

41 Refractor

42 Reflector Secondary mirror Primary mirror Newton Primär Cassegrain Coudé Focus Focus Focus Focus

43 The biggest reflecting telescopes on Earth ESO VLT 4 x 8,2m Chile LBT 2 x 8,4m 2004 Arizona Keck 9,8m 1991 Hawaii SALT 11m 2005 South Africa Hobby-Eberle 9,2m 2000 Texas MMT 6,5m 2000 Arizona Selentschukskaja 6,1m 1975 Caucasus Palomar (Hale) 5,1m (200 Zoll) 1948 California Herschel 4,2m 1987 La Palma

44 Kitt Peak Observatory

45 Kitt Peak Observatory

46 Kitt Peak Observatory

47 Kitt Peak Observatory

48 Kitt Peak Observatory

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50 Hubble Space Telescope

51 The biggest telescope in space: Hubble Space Telescope 2,4m (HST)

52 Hubble Space Telescope Lyman Spitzer

53 Hubble Space Telescope Polishing of Hubble's primary mirror

54 Hubble Space Telescope Early stages of Hubble's construction, 1980

55 Hubble Space Telescope Shuttle mission STS-31 lifts off, carrying Hubble into orbit.

56 Hubble Space Telescope The light from a star spread over a wide area instead of being concentrated on a few pixels

57 Hubble Space Telescope Astronauts work on Hubble during the first servicing mission

58 Hubble Space Telescope Improvement in Hubble images after the first service mission

59 Hubble Space Telescope One of Hubble's most famous images: pillars of creation where stars are forming in the Eagle Nebula.

60 Hubble Space Telescope Distant galaxies in deep space in a Hubble Ultra Deep Field photograph

61 Hubble Space Telescope Horsehead Nebula

62 See you next Monday!