Gary Newport

Home/Talks/03

Astrophysics

Before the Main Sequence

What STELCOR does to the earliest phase of an 8 to 60 solar mass star, and which assumptions the answer is hostage to.

Running time
60 minutes
Audience
Departmental seminar, research group
Format
Seminar with discussion
Remote
Yes

Massive stars are conventionally modelled from the zero-age main sequence onward, on the reasonable grounds that they arrive there quickly and that the arrival erases most of the detail. This talk asks what that convenience costs.

I present the structure of STELCOR, the treatment of accretion and rotation during the approach, and the resulting spread in surface abundances and rotation rates at the point where most grids begin. I then set out, honestly, which of these results are robust and which are artefacts of a choice I had to make.

The last third is about observational discrimination: what a survey would need to measure, and to what precision, to tell these models apart.

What people leave with

  • Where pre-main-sequence assumptions propagate into main-sequence predictions
  • The sensitivity of surface abundance spreads to accretion history
  • Which observations would actually adjudicate between the models

What the room needs

  • Projector or large screen
  • Whiteboard useful
  • Fifteen minutes for discussion

Where it sits

This talk is ringed. The others are links.