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Canterbury 01.09.2014 The problem of star formation is not how to make stars. The problem of star formation is how not to make stars.

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Presentation on theme: "Canterbury 01.09.2014 The problem of star formation is not how to make stars. The problem of star formation is how not to make stars."— Presentation transcript:

1 Canterbury 01.09.2014 The problem of star formation is not how to make stars. The problem of star formation is how not to make stars.

2 Canterbury 01.09.2014 The Physics of Star Formation Dr Dirk Froebrich University of Kent

3 Canterbury 01.09.2014 - How do we know stars are forming? - Where do stars form? - Properties of young stars - Temperature & Turbulence vs. Gravity - Collapse, Discs and Jets Content

4 Canterbury 01.09.2014 - How do we know stars are forming? - Where do stars form? - Properties of young stars - Temperature & Turbulence vs. Gravity - Collapse, Discs and Jets Content

5 Canterbury 01.09.2014 Inside Stars... Massive stars are bright and short lived (few Million years)

6 Canterbury 01.09.2014 The Sky Gal. CenterGal. Plane Gal. North Pole Gal. South Pole

7 Canterbury 01.09.2014 Massive O-Stars

8 Canterbury 01.09.2014 Massive OB-Stars

9 Canterbury 01.09.2014 OB-Stars + Dust

10 Canterbury 01.09.2014 OB-Stars + Dust Gal. CenterGal. Plane Gal. North Pole Gal. South Pole

11 Canterbury 01.09.2014 The Circinus Cloud

12 Canterbury 01.09.2014   B68

13 Canterbury 01.09.2014 - How do we know stars are forming? - short lived massive stars exist - they must have formed in the last few Myrs - the Universe is 13.7Gyrs old Content

14 Canterbury 01.09.2014 - Where do stars form? - in or near Giant Molecular Clouds mostly molecular hydrogen + 1% dust + traces of CO, H 2 O, NH 3,... - these clouds are massive (10 4 -10 6 M SUN ) - these clouds are cold (10-30K) Content

15 Canterbury 01.09.2014 - How do we know stars are forming? - Where do stars form? - Properties of young stars - Temperature & Turbulence vs. Gravity - Collapse, Discs and Jets Content

16 Canterbury 01.09.2014 Region S106: 150 young stars forming in Cygnus Subaru Observatory

17 Canterbury 01.09.2014 Region NGC346: young stars forming in the LMC Hubble Space Telescope

18 Canterbury 01.09.2014 Tarantula Nebula: young stars forming in the LMC Hubble Space Telescope

19 Canterbury 01.09.2014 Subaru Telescope Orion Nebula

20 Canterbury 01.09.2014 - Properties of young stars - they are ‘social‘ – most form in clusters, some in isolation - single/binary/tripple/multiple – 147/64/9/1 - many low mass and few high mass stars, universal mass distribution Content

21 Canterbury 01.09.2014 - How do we know stars are forming? - Where do stars form? - Properties of young stars - Temperature & Turbulence vs. Gravity - Collapse, Discs and Jets Content

22 Canterbury 01.09.2014 OriB OriA  Ori Betelgeuse ONC NGC2024 NGC2071 MON R2 The Problem: 10s of light years

23 Canterbury 01.09.2014 The Problem: OriB OriA  Ori Betelgeuse ONC NGC2024 NGC2071 MON R2 10s of light years Solar Diameter Size: 10 16 m  10 9 m 7 orders of magnitude(x 10.000.000) Density: changes by 21 orders of magnitude (x 1.000.000.000.000.000.000.000)

24 Canterbury 01.09.2014 The Problem: OriB OriA  Ori Betelgeuse ONC NGC2024 NGC2071 MON R2 10s of light years Solar Diameter Gravity But why has not everything collapsed? Thermal Pressure of gas clouds  critical (Jeans) mass for collapse about 1M SUN for a cloud of 1ly radius

25 Canterbury 01.09.2014 The Problem: OriB OriA  Ori Betelgeuse ONC NGC2024 NGC2071 MON R2 10s of light years Solar Diameter Gravity Gravity vs. Thermal pressure Almost all clouds are above Jeans limit  should collapse  But we do not observe this! Solution: Turbulence

26 Canterbury 01.09.2014 The Problem: OriB OriA  Ori Betelgeuse ONC NGC2024 NGC2071 MON R2 10s of light years Solar Diameter Gravity Turbulence: random bulk motion of material at supersonic velocities v>sound speed (200m/s) creation of shocks increasing density

27 Canterbury 01.09.2014 The Problem: OriB OriA  Ori Betelgeuse ONC NGC2024 NGC2071 MON R2 10s of light years Solar Diameter Gravity Gravity vs. Thermal pressure + Turbulence Star Formation is the interplay of Gravity and supersonic turbulence in Molecular Clouds  Gravoturbulent Fragmentation

28 Canterbury 01.09.2014 - How do we know stars are forming? - Where do stars form? - Properties of young stars - Temperature & Turbulence vs. Gravity - Collapse, Discs and Jets Content

29 Canterbury 01.09.2014 Stage 1Stage 2Stage 3 Now, how does it work?

30 Canterbury 01.09.2014 Now, how does it work?

31 Canterbury 01.09.2014

32 Orion Nebula: Discs seen in silhouette

33 Canterbury 01.09.2014

34 HH 46/47

35 Canterbury 01.09.2014 HH 212

36 Canterbury 01.09.2014 HH 46/47 HST 1994 - 1997

37 Canterbury 01.09.2014 HH 46/47 HST 1994 - 1997

38 Canterbury 01.09.2014 HH 34 HST 1994 - 1997

39 Canterbury 01.09.2014 HH 34 HST 1994 - 1997

40 Canterbury 01.09.2014 The Problem: OriB OriA  Ori Betelgeuse ONC NGC2024 NGC2071 MON R2 10s of light years Solar Diameter Gravity Gravity vs. Thermal Pressure + Turbulence + angular Momentum + magn. Fields Spin  accretion disc formation  ejection of jets (accelerated and collimated by magnetic fields)  feedback from outflows and radiation  turblence

41 Canterbury 01.09.2014 Planet Formation

42 Canterbury 01.09.2014

43 The end


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