Helium Stars, Heavy Metals, High Velocities and Explosions 

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• Simon Jeffery (Armagh)
• Thursday 31 January 2019, 16:00-17:00
• Sackler Lecture Theatre, IoA (tea at 3:30 pm).

If you have a question about this talk, please contact ma557.

The term “hot subdwarf” refers to stars which are smaller than hydrogen-burning main-sequence stars and larger than white dwarfs. It includes stars in several different advanced stages of evolution. Most have surfaces severely depleted in either hydrogen or helium; some explanation exists for most of these. My talk will review the general properties of helium-poor and helium-rich subdwarfs and contemporary models for their origins. 

I will introduce the extremely rare “intermediate helium subdwarfs”, which pose significant challenges.  Several show extraordinary surface abundances of the heavy metals zirconium, yttrium, strontium, germanium and lead. All of these heavy-metal stars are on high-energy galactic orbits. Two pulsate in modes which, until now, were thought to be impossible. Now, new theoretical results force us toward new questions and new ideas about the origin of these stars. 

This talk is part of the Institute of Astronomy Colloquia series.

This talk is included in these lists:

• Cambridge Astronomy Talks
• Combined External Astrophysics Talks DAMTP
• Cosmology lists
• Cosmology, Astrophysics and General Relativity
• Institute of Astronomy Colloquia
• Institute of Astronomy Talk Lists
• Kavli Institute for Cosmology Talk Lists
• Priscilla
• Sackler Lecture Theatre, IoA (tea at 3:30 pm)

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