Interstellar Cloud topology with Gaia and Herschel

Short Description

Starting point / motivation

Understanding the origin of stars is one of the fundamental open topics in Astrophysics as it directly impacts the understanding of galaxy formation and evolution and the formation of planets. Today, we know that stars form in the coldest, darkest, and densest regions of our Milky way, in the interstellar molecular clouds.

One of the most pressing questions in star formation research relates to the essentially unknown shapes, orientations, and 3D dynamics of this star-forming molecular clouds. These yet unknown properties hold the key to understand their formation process.

Contents and goals

In this proposal, we plan to make use of an innovative method recently developed by our group, a method based on ESA Gaia and Herschel data, to derive for the first time 3D shapes and accurate distances to local molecular clouds. To this end we use young stellar objects (YSOs), that have "recently" formed in these clouds, and are therefore still spatially connected to them.


By using parallax measurements from the groundbreaking Gaia mission we can now determine accurate distances to these YSOs and with this we can also determine indirectly the distances to their harbouring clouds. Complementary, we use ESA Herschel data, to know the exact 2D extend of the star-forming dense molecular cloud.

This method was already tested in our pilot study, where we studied the giant molecular cloud Orion A. This is the closest high-mass star-forming region to our earth, harbouring a rich sample of young stars. With this, a detailed analysis of cloud distances across the whole complex was possible. We found that a large part of the cloud is inclined in a angle away from the plane of the sky, which signifies that the cloud is about twice as long as previously assumed.

Comparing this to other recent methods based on Gaia data, which also measure accurate distances to nearby clouds, we find, that our method is better suitable to determine distance variations within one single cloud.

Expected results

Due to the success of our method we developed this research project to deploy our method to further nearby star-forming regions and to extend it by also investigating the clouds 3D space motions. This is possible by using archival data and recent NIR data taken by our group (ESO VISIONS Public Survey), with which we will then be able to associate cloud space motion with cloud shapes.

In combination with the star formation history, estimated from star formation rates and efficiencies, we can now deliver a more complete image of these nearby molecular clouds. With this we will open a completely unexplored window on how nature transforms diffuse gas into star-forming factories.

Project Partners


University of Vienna - Institute for Astrophysics

Contact Address

University of Vienna
Institute for Astrophysics
Mag. Josefa Großschedl
Türkenschanzstrasse 17
A-1180 Vienna