Site Map
Follow us on Facebook Follow us on Twitter YouTube channel
Centro de Astrofísica da Universidade do Porto

An improved classification of B[e]-type stars

H. J. G. L. M. Lamers, F.-J. Zickgraf, D. de Winter, L. Houziaux, J. Zorec

We review the classification criteria for the B[e]-type stars (B type stars with forbidden emission lines in their optical spectrum) and we express these in terms of physical characteristics of the stars and the circumstellar (CS) matter. We show on the basis of observations that these criteria can be met in different kinds of stars of different mass and different evolutionary stages. We propose that the name "B[e]phen" is more appropriate than the name "B[e] stars". We propose the definition of five classes of stars which show the B[e]phen: B[e]gin{itemize} [(a)] B[e] supergiants or "sgB[e] stars" [(b)] pre-main sequence B[e]-type stars or "HAeB[e] stars" [(c)] compact planetary nebulae B[e]-type stars or "B[e]ppn stars" [(d)] symbiotic B[e]-type stars or "SymB[e] stars" [(e)] unclassified B[e]-type stars or "unclB[e] stars" The primary and secondary classification criteria for each of these groups are defined. We also present lists of objects for each group, except for the SymB[e] stars. It is possible that some stars satisfy the criteria for more than one of the classes sgB[e], HAeB[e], cPNB[e] and SymB[e]. In that case the evolutionary phase of the star is unclear and the star should be assigned to class unclB[e].

Astronomy and Astrophysics
Volume 340, Page 117
December 1998

>> ADS

Institute of Astrophysics and Space Sciences

Institute of Astrophysics and Space Sciences (IA) is a new but long anticipated research infrastructure with a national dimension. It embodies a bold but feasible vision for the development of Astronomy, Astrophysics and Space Sciences in Portugal, taking full advantage and fully realizing the potential created by the national membership of the European Space Agency (ESA) and the European Southern Observatory (ESO). IA resulted from the merging the two most prominent research units in the field in Portugal: the Centre for Astrophysics of the University of Porto (CAUP) and the Center for Astronomy and Astrophysics of the University of Lisbon (CAAUL). It currently hosts more than two-thirds of all active researchers working in Space Sciences in Portugal, and is responsible for an even greater fraction of the national productivity in international ISI journals in the area of Space Sciences. This is the scientific area with the highest relative impact factor (1.65 times above the international average) and the field with the highest average number of citations per article for Portugal.

Proceed on CAUP's website|Go to IA website