The formation of stars and planets: The formation of stars and planets Lecture by C.P. Dullemond Max-Planck-Institute for Astronomy Heidelberg Image credit: Michael Sherick


Sorry about:: Sorry about: Topic of Star- and Planet Formation is too vast to cover completely, and in sufficient depth, in 15 hours. We will have to gloss over many things... Many important topics not included, for example: Origin of ‘metal’-enriched matter from which we are built Star formation on galactic scale (e.g. star-burst galaxies) Chemistry of star formation, photodissociation of molecules Pre-main sequence stellar evolution High-mass star formation (unless voluntary extension!)


Literature:: Literature: S.W. Stahler andamp; F. Palla, 'The formation of stars' L. Hartmann, 'Accretion processes in star formation' The review ‘bibles’ of star and planet formation: Protostars and Planets II Protostars and Planets III Protostars and Planets IV (next year) Protostars and Planets V


Thanks to ...... for material: Thanks to ...... for material Ewine van Dishoeck Carsten Dominik Christian Fendt Anders Johansen Klaus Pontoppidan Frithjof Brauer Sascha Quantz *Many others* The field of star and planet formation is quite a large field. I have received lots of very valuable information and material from the following people, to whom I am indebted:


Technical notes on the lecture:: Technical notes on the lecture: Target group: PhD students and advanced undergraduate students Physics and astrophysics Goals: Half overview, half in depth Mostly theory, but strong link to observations Powerpoint material will be put on my web site: www.mpia.de/homes/dullemon/lectures/starplanet/


Technical notes on the lecture:: Technical notes on the lecture: Style of lecture : Working out simple analytical models (of cloud cores, of disks, of particle motion, particle agglomeration etc.) Discussion of state-of-the-art models with physical explanation. Comparison of models with observations We need solid basis in the physics of astrophysics (hour 2+3) But first a quick overview... in pictures and movies


The formation of stars and planets : The formation of stars and planets Day 1, Topic 1: Introduction and Overview Lecture by: C.P. Dullemond


Birthplace of stars: Molecular Clouds: Birthplace of stars: Molecular Clouds Ophiuchus Giant Molecular Cloud (by Loke Tan)


Birthplace of stars: Molecular Clouds: Birthplace of stars: Molecular Clouds Ophiuchus Giant Molecular Cloud (by Loke Tan)


Forming stars from Molecular Clouds: Forming stars from Molecular Clouds M. Bate Exeter UK Very dense Molecular Cloud: very aggressive star formation


‘Isolated’ Star Formation: ‘Isolated’ Star Formation M.Hogerheijde1998, after Shu et al. 1987


In the beginning...: In the beginning... Stars are born deep in very cold dark (optically thick) clouds. Their birth is ‘secret’: not visible at optical wavelength. Infrared telescopes can penetrate through these clouds and witness the first signs of life from a protostar


Feeding the infant star...: Feeding the infant star... Infall of matter onto protostar is energetic: lots of radiation In above image some radiation escapes via cavity. Most of radiation escapes at long wavelength (infrared), because cloud is transparent at those wavelength. Far-IR wavelength telescopes have low resolution so far, so what’s really happening down there is still difficult to study. McNeal’s Nebula


Not all ‘food’ is welcome: outflows...: Not all ‘food’ is welcome: outflows...


Not all ‘food’ is welcome: outflows...: Not all ‘food’ is welcome: outflows...


A zoom-in to a massive star forming region: A zoom-in to a massive star forming region Picture credit: W. Keel


A zoom-in to a massive star forming region: A zoom-in to a massive star forming region Eagle Nebula (M16) Picture credit: T.A. Rector andamp; B.A. Wolpa


A zoom-in to a massive star forming region: A zoom-in to a massive star forming region Eagle Nebula (M16) Picture Credit: J. Hester andamp; P. Scowen


A zoom-in to a massive star forming region: A zoom-in to a massive star forming region Eagle Nebula (M16) Picture Credit: J. Hester andamp; P. Scowen


A zoom-in to a massive star forming region: A zoom-in to a massive star forming region Picture Credit: J. Hester andamp; P. Scowen Eagle Nebula (M16)


Clearing of the remnant birth cloud: Clearing of the remnant birth cloud


A star+disk appears...: A star+disk appears...


A star+disk appears...: A star+disk appears... HST image of AB Aurigae by Carol Grady


Planets form in the disk (?): Planets form in the disk (?) Artist’s impression of planet formation...


Grinding asteriods back to dust...: Grinding asteriods back to dust...


Grinding asteriods back to dust...: Grinding asteriods back to dust... Planets and asteroids have formed, some asteroids get destroyed and produce the dust you observe in the image. Can the dust trace the location of (invisible) planets?


Slide27: The early life of a newly formed star


Zero-age main sequence (ZAMS): Zero-age main sequence (ZAMS) Oh, Be A Fine Girl, Kiss Me (Right Now Sweety!) O B A F G K M The Harvard classification. Annie Jump Cannon, Henry Draper


Pre-main-sequence: the infancy of a star: Pre-main-sequence: the infancy of a star Palla andamp; Stahler


Pre-main-sequence: the infancy of a star: Pre-main-sequence: the infancy of a star Protostar = self-gravitating hot ball of gas, continuously being fed by accreting matter At first: no internal nuclear heat production Star cools by radiation: Kelvin-Helmholz time scale Star contracts, central density and temperature increases (!) Deuterium ignites as soon as Tc andgt;= 1x106 K Thermostat: ds/dTcandlt;0, i.e. too hot: star swells, Tc goes down, and deuterium burning slows Star becomes fully convective Stellar radius inflates: can reach 3...5 R.


Pre-main-sequence: the infancy of a star: Pre-main-sequence: the infancy of a star (We are now in the T-Tauri star phase) Star contracts slowly with constant temperature for low mass stars, i.e. they move vertically downward in the HR diagram Tc and c increase until: Hydrogen ignition Prolonged hydrogen burning starts This is the start of the ‘adult’ life of the star Star reached the ZAMS


Age and mass determination of PMS stars: Age and mass determination of PMS stars Testi et al. Martin et al.


A brief history...: A brief history... 1755: Kant postulates that solar system formed from ‘Urnebel’ (‘solar nebula’) 18th-19th: Observations of dark clouds 1904: Hartmann: Discovery of interstellar gas 1930: Trumpler: Discovery of interstellar dust 1944: von Weizsäcker forwards idea that planets formed in vortices in a turbulent protoplanetary disk (=solar nebula) 1952: Lüst develops first real theory of pp accretion disk 1960-70’s: Mapping of interstellar clouds (HI 60’s, CO: 70’s) 1961: Hayashi: first theory of pre-main sequence evolution 1977: Shu: first theory of cloud collapse 1969: Safronov published theories of accumulation of solid particles and planet formation (most of his theories are still highly relevant today!)


A brief history...: A brief history... 1980’s: IRAS satellite maps at 12, 25, 60 and 100 m: discovery of many young stellar objects (YSOs). 1984/1987: Lada andamp; Wilking, Adams, Shu andamp; Lada: YSO classification and evolutionary sequence (class I, II, III). 1984: Auman et al. Smith andamp; Terrile: discovery of disks around mature main-sequence A stars (Vega, -Pic). Late 80s/early 90s: Infrared and sub-mm observatories: indirect evidence of disks. Mid 90s: Hubble images of disks: direct evidence for disks 1995/1996: Mayor andamp; Queloz (1995), Marcy andamp; Butler (1996): discovery of extrasolar planets around solar type stars andgt;1995: Explosion of research on disks and extrasolar planets.


Overview of the lecture: Overview of the lecture Day 1: Introduction Radiation physics Hydrodynamics and Magnetohydrodynamics Day 2: Giant Molecular Clouds Self-gravitating hydrostatic spheres Collapsing clouds Day 3: Viscous evolution of protoplanetary disks 1+2 Irradiated protoplanetary disks, SEDs, observations Day 4: Magnetospheric accretion, jets, outflows Motion of particles in disks Agglomeration of particles in disks Day 5: The solar system and extrasolar planets Formation of planets Migration of planets and outlook