Scientific Rationale

Ever since the identification of Herbig Ae/Be (HAeBe) stars as a class of early-type pre-main sequence objects, they have taken centre-stage in star and planet formation. Their stellar masses correspond to the transition regime between the formation of solar-type stars and high-mass stars, i.e. the dichotomy between clustered and isolated formation, between disk accretion and magneto-spheric accretion, between convective and radiative stellar interiors, between slow and fast rotators. The disks around HAeBe stars evolve in harmony with planet formation towards debris disks and mature planetary systems. Their relative proximity makes HAeBes generally bright at most wavelengths and allows a detailed view of their evolving environment.  As such, Herbigs are pivotal for both the formation of stars and planets.

ESO's innovative edge on optical/IR instrumentation has led the way toward ground-breaking progress, especially in the field of the HAeBe stars. Powerful spectroscopic instruments like CRIRES and X-shooter,
and the VLTI's interferometric instruments MIDI, AMBER, and PIONIER have for the first time opened up the milli-arcsecond and sub-milli-arcsecond spatial scales where the disk physics takes place and planetary formation processes occur. ALMA will complement spatially and advance spectrally at high resolution the connection between the inner disks and the outer, dusty disks as observed by recent space-based observatories such as ISO, Spitzer, and Herschel. Future instruments like SPHERE, GPI and VLTI/MATISSE will contribute significantly to uncovering the young planets within the young disks. The time is ripe for a dedicated meeting to promote the new results obtained with the various high resolution techniques, both angular and spectroscopic. It is timely to review the state of the field after 20 years since the 1993 Amsterdam workshop dedicated to HAeBe stars.

The 2014 ESO HAeBe workshop will highlight the different mechanisms prevalent in high and low-mass SF and the evolutionary link between star/planet birth and mature stellar/planetary systems. The high-resoluton observational and theoretical advances achieved in the past 10 to 15 years provide the motivation for this HAeBe workshop. The evolution of the circumstellar disk material is the emphasis but not the exclusive topic of the workshop. The following will be addressed:

  • disk structure
  • accretion, its geometry and evolution
  • transitional disks and disk dispersal
  • young clusters, multiplicity and mass function
  • dust processing and grain growth
  • debris disks
  • jets and outflows
  • rotation and activity
  • ages, evolutionary status and stellar interiors
  • impact of future instruments