Applications of

Radiative Transfer

to stellar and planetary atmospheres
Tenerife, Spain - 13-17 Nov. 2017

Outline of the School

The radiative transfer (RT) equation is the master key for the determination of the physical parameters and chemical abundances of the stars by means of model atmospheres and the subsequent spectral synthesis. The progress achieved so far in the field of stellar atmospheres is expected to pave the way to new successful applications of RT to planetary atmospheres. The proposed leitmotiv for the XXIX Canary Islands Winter School of Astrophysics is to discuss the physical and geometrical properties of the stellar and planetary atmospheres in order to ascertain their influence on the radiative transfer equation, considered as a kinetic (Boltzmann) equation for photons.

Of course, an exhaustive treatment of such a far-reaching subject would largely trespass the limits of time allotted to this Winter School. Two questions have been put forward as a criterion to select among the wide range of possible topics: Which are the problems posed by the physical properties of the different classes of objects (i.e. stellar and planetary atmospheres) considered? How do they shape the mathematical structure of the RT equation?

The phenomenology of early-type stars, late-type stars and planetary atmospheres will be examined in order to address the main physical processes inside each individual class of objects and to identify the problems they pose from the standpoint of RT. Among them, departure from Local Thermodynamical Equilibrium (LTE) is an almost ubiquitous phenomenon and will be duly considered. At least a hint upon the effects on line profiles brought about by large velocity fields and shocks propagating through extended atmospheres shall be given as well. Specific problems related to the peculiar physical conditions of planetary atmospheres shall be addressed too.

From the mathematical and modelling point of view, specific lectures will be included to indicate how, on the one hand, departures from hydrodynamic equilibrium prevent to introduce in the left hand side of the RT equation the usual simplifying approximations (stationarity, homogeneity, 1-D plane-parallel or spherical geometry) and, on the other hand, departures from LTE must often be taken into account in the right hand side of the equation, which results in the coupling of all the specific RT equations and a consequent severe non-linear and non-local problem.

Distinguished specialists in their field of research have been invited to give advanced lectures on the following topics:

  • Fundamental physical aspects of radiative transfer
  • Mathematical background and computer codes
  • Phenomenology and physics of atmospheres of early-type and late-type stars
  • Phenomenology and physics of atmospheres of brown dwarfs and extrasolar giant planets
  • Near IR high resolution spectroscopy

Lectures will be complemented by tutorial activity consisting in the running of  standard computer codes to trace the effects of both physical assumptions and a different choice of  key parameters on the stellar spectra synthesized in the case of both hot and cool stars.

The School is primarily intended for PhD students and recent postdocs in any field of research in Astronomy. Participants will have the opportunity to display their current work by presenting a poster. The format of the School will also encourage close interaction between students and lecturers.

The Winter School will take place at San Cristóbal de La Laguna (Tenerife, Canary Islands, Spain) from Monday 13th to Friday 17th November 2017. The lectures will be delivered in English and will be published by Cambridge University Press in a dedicated monograph, which will be sent free of charge to all the participants. Speakers will present their topics in a series of three lectures. Visits to the IAC's Headquarter in La Laguna, the Teide Observatory in Tenerife and the Roque de los Muchachos Observatory in La Palma will be scheduled as part of the activities.

Those interested in attending the Winter School should register following the instructions provided in the Registration page. Once registered, please login to the personal area of the website and complete the required information. In addition we request a letter of reference from a thesis advisor or Head of Department which should be emailed to winter@iac.es. These should reach the IAC before June 23rd. Selected candidates will be informed by the end of July.