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Cores to Clusters Star Formation with Next Generation Telescopes

:	M. S. N. Kumar, M. Tafalla, P. Caselli
:	M.S. Nanda Kumar, M. Tafalla, P. Caselli
:	Cores to Clusters Star Formation with Next Generation Telescopes
:	Springer-Verlag
:	9780387263571
:	1
:	CHF 189.50
:

:	Astronomie
:	English

:	222
:	Wasserzeichen/DRM
:	PC/MAC/eReader/Tablet
:	PDF

It was with pleasure that CAUP became for three days the core to the cloud of star formation experts all over the world. Close to the celebration of its 15th anniversary - therefore still in the early stages of institutional evolution - we are proud of our multiple activities in Astronomy: a productive research centre, classi?ed as 'Institution of excellence' within the Portuguese research units, but also an 'Institution of Public Utility' as recognised by the Government. Fifteen years ago we choose to play a role not only in research, as expected from any research centre but also in the training of the future astronomers and the promotion of science and scienti?c culture. This choice is clearly stated in our by-laws and also in the multiple activities we have carried out since. Along the years we have organized on a regular basis international Workshops similar to 'Cores to Clusters'. Sometimes we have chosen to organize int- national conferences of a larger size. On other occasions the choice has been for smaller and more informal discussion meetings. Or even doctoral schools with very different objectives. In common all those meetings have always had, besides the formal registered participants, a group of informal participants, our undergraduate students of Astronomy, so eager to be in touch with the real world.

	Contents	7
	Foreword	12
	I REVIEW ARTICLES	15
	PHYSICAL PROPERTIES OF PRESTELLAR CORES	16
	Introduction	16
	Basic Ideas	17
	Determining Physical Parameters of Star Forming Regions	20
	Mass determinations	21
	Temperatures	21
	Densities	23
	Magnetic Field and Ionization Degree	24
	Future Prospects	25
	Acknowledgments	25
	References	25
	IMPULSIVELY TRIGGERED STAR FORMATION	28
	Introduction	28
	Fragmentation of a shock-compressed layer	29
	Larson s scaling relations and the clump mass spectrum	30
	The critical pressure for rapid star formation	32
	The minimum mass for star formation	33
	The fragmentation of shells swept up by expanding nebulae	36
	Pre-existing cores subjected to a sudden increase in external pressure	37
	Forming free-floating brown dwarves and planetary-mass objects by photo-erosion	38
	Forming low-mass companions and free-.oating objects in interactions between protostellar discs	39
	Conclusions	40
	Acknowledgments	40
	References	41
	STARLESS CORES	44
	Introduction	44
	Classical studies of starless cores	45
	Starless cores studies in the 1990s	46
	The internal structure of the l1498 and L1517B cores	48
	Density	50
	Turbulence	52
	Molecular composition	53
	Tracing core evolution with molecular freeze out	55
	L1521E: the youngest starless core?	57
	Acknowledgments	58
	References	58
	CHEMICAL PROCESSES IN STAR FORMING REGIONS	60
	Introduction	60
	Basic concepts in astrochemistry	61
	Gas phase chemistry	62
	Surface chemistry	64
	References	74
	PROTOSTELLAR JETS: A HIGH ANGULAR RESOLUTION PERSPECTIVE	80
	Introduction	80
	Properties of stellar jets	82
	High angular resolution observations	84
	Optical, NIR and Sub-mm Interferometry	87
	Conclusions: universality of the accretion/ejection engine	88
	Acknowledgments	89
	References	89
	NON-ISOTHERMAL GRAVOTURBULENT FRAGMENTATION	90
	Introduction	91
	Thermal properties of star-forming clouds	92
	Numerical Approach	93
	Dependency of the Characteristic Mass	94
	Summary	96
	Acknowledgments	98
	References	98
	THE BIRTH OF MASSIVE STARS AND STAR CLUSTERS	100
	Introduction	100
	Overview of physical properties	101
	Setting up initial conditions for star cluster formation	102
	How do stars form within clusters?	104
	Formation of Cores	104
	Accretion to Stars	105
	Assumptions and Predictions of the McKee-Tan Model	106
	Observational Evidence for Massive Star Formation from Cores and Accretion Disks	108
	The timescale of star cluster formation	110
	How does feedback affect the formation process?	111
	Feedback in Individual Cores	111
	Feedback during Star Cluster Formation	112
	Feedback on GMCs	113
	Acknowledgments	113
	References	114
	PRECURSORS OF UCHII REGIONS AND THE EVOLUTION OF MASSIVE OUTFLOWS	118
	Precursors of UCHii regions	118
	High-Mass Protostellar Objects (HMPOs)	119
	High-Mass Starless Cores (HMSCs)	123
	Massive molecular out.ows: an evolutionary scenario	124
	Summary of observational constraints	124
	A potential evolutionary scenario	127
	Discussion and potential caveats	129
	References	130
	OBSERVATIONS OF ACCRETION ONTO HIGH MASS STARS	134
	Introduction	134
	Observations	137
	The Accretion Flow	137
	A simple model of the accretion .ow	140
	Implications for star formation by accretion	142
	References	142
	DISKS AROUND MASSIVE (PROTO)STARS	144
	The dividing line between high- and low-mass stars	144
	Possible scenarios for high-mass star formation	145
	Evidence for disks in massive (proto)stars	146
	Disks traced by maser lines	146
	Disks traced by continuum emission	147
	Disks traced by thermal line emission	148
	Conclusions	151
	References	152
	EMBEDDED CLUSTERS	154