About the Project


What does ICYBOB stand for?
Initial Conditions for YMCs and OB associations

What does YMCs stand for?
Young Massive Clusters

What are the main scientific goals of ICYBOB?
The goal of this proposal is to establish a new era of stellar cluster evolution research by performing numerical simulations on different scales, and of different stages of a cluster’s life, from the formation of YMCs, the formation and evolution of OB associations, to the evolution of clusters and associations in galaxies.

Key questions include:
i) How does gas disperse from new clusters and what happens to that gas?
ii) How do YMCs form?
iii) How do new clusters and Giant Molecular Clouds evolve into OB associations?
iv) How long can clusters survive for as they orbit a galaxy and what causes their destruction?

Who funds ICYBOB?
We are funded by the European Research Council H2020-EU.1.1 (Grant No. 818940)

Where is ICYBOB based?
University of Exeter

Are your results published?
Yes – these are listed on our Publications page

Where can I read about your results?
Links to the articles are given on the Publications page. In addition, we have created movies from our cluster simulations which can be viewed on our Movies page.

Do you give talks to the general public/schools?
Yes – please contact us for more information or to arrange a talk.

How can I contact you?
Our contact info is listed on the Contact Us page.


The Science


What is a star cluster?
A group of stars in space gravitationally bound together. There are 2 main types of clusters: Open Clusters which are part of the star formation process of our galaxy, and Globular clusters which are not.

At ICYBOB we are trying to better understand how Young Massive open Clusters (YMCs) and OB associations form and evolve.

What makes a cluster “young”?
The definition of a ‘young’ cluster is a subjective term, and is normally based on the context in which the research is taking place. Here at ICYBOB we focus of clusters which are less than 5Myrs old.

What makes a cluster “massive”?
A cluster is considered massive if the total mass of the member stars is greater than 104 times that of our Sun.

What is an OB association?
An association is a group similar to an open cluster but with fewer stars, that have become gravitationally unbound. OB associations are young (<10Myrs) and have some of the most massive stars (O and B type) in our Galaxy as members.

How do YMCs and OB associations form?
Both are formed within Giant Molecular Clouds (GMCs), and there are several mechanisms that can trigger star formation. Here at ICYBOB we research the formation of YMCs and OB associations triggered by two GMCs colliding (a.k.a ‘cloud-cloud collision’).

What are “properties” of YMCs and OB associations?
Spatial and kinematic characteristics such as how old they are, distance from Earth, how reddened they appear to be (due to the presence of dust in the GMC and in the Galaxy between us and them), the spatial distribution of members, the dynamics of members etc.

What is stellar feedback?
The release of mass, energy and momentum by massive (O and B type) stars.




What qualifications are needed to work on a project like ICYBOB?
To become a astrophysics researcher, a PhD in astrophysics is required (though you can work on a project like ICYBOB for your PhD).

I’m currently in high school and interested in becoming an astrophysicist... where do I start?
Maths and Physics are essential courses to take to become an astrophysicist, and will be needed for entry onto any accredited physics-based University degree. Computing and astronomy courses are beneficial to take, if your school offers these.