PROTEUS

Starting point / motivation

Among the fundamental properties necessary to understand the formation of stars and planets are the characteristic timescales that describe each stage of protostellar growth. Major phases and durations are currently defined under a classification scheme developed more than 20 years ago. This relies mainly on the characteristics of dust emission depicting the development of structures such as accretion disks and envelopes surrounding the stellar embryo.

Dust-based proxies alone however, cannot detail protostellar growth, as they are prone to large uncertainties; consequently timescales derived from protostellar population-statistics remain dubious. It comes therefore as no surprise when recent, high fidelity data indicate that our yardstick has been too long: planets seem to form much earlier than ever assumed and most likely, synchronously to protostars.

Contents and goals

We here argue that it is imperative to readjust the standard classification scheme and its characteristic timescales to reflect the much more complex processes that regulate the formation of stars. These processes include

• the mechanical feedback through mass, energy and momentum transport, both inwards, via mass-accretion, but also outwards, via the action of jets and outflows and
• the influence of radiation originating from shocks along the mass-flow channels and the activity of the protostar.

Methods

In this project we aim to reverse-engineer the feedback processes that mainly reflect in the excitation of gas, in an effort to derive independent criteria that will describe the coevolution of all major structural components involved in star-formation.

Expected results

These criteria along with the standard, dust-based scheme will lead to a more exact classification that will place stringent limits on protostellar evolution and inferred timescales. The implications of such readjustment can reach far beyond star formation, in fields such as the evolution of the early the solar system and the prerequisites for planetary habitability.

Coordinator

University of Vienna - Institute for Astrophysics

University of Vienna
Institute for Astrophysics
Dr. MMag. Odyssefs Dionatos
Türkenschanzstraße 17
A-1180 Wien