Professor Simon Jeffery

Professor Simon Jeffery

Simon’s astronomical life started in Edinburgh, and has taken him via a Physics degree at Imperial College, London, to St Andrews, Scotland and Kiel, Germany, before finally moving to the Armagh Observatory and Planetarium in Northern Ireland, where he works as a senior research astronomer. He is also adjunct Professor of Physics at Trinity College Dublin and recently held a Visiting Byfellowship at Churchill College, Cambridge.

Following a lifelong interest in how stars work and how they vary over time, Simon’s PhD in theoretical stellar structure and evolution was followed by pursuing observational and theoretical work on stellar pulsations and atmospheres. Most stars never fully exhaust their initial hydrogen store, but retain a hydrogen surface to the very end. However, in rare and extreme cases, some stars become true ‘helium’ stars. Simon’s goal is ultimately to demonstrate their elusive origins. The surprising conclusion is that the great majority appear to have formed from the merger of two very old and faint stars … a double white dwarf. His favourite is the pulsating V652 Herculis — the ‘born-again rocket star’.

Simon and his wife Angela have three children. Simon would like to spend more time dinghy racing, sings baritone, and hunts big game and wild seascapes with a camera.

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Publications

Refereed Papers on ADS

Data

• Model Atmospheres : Model atmospheres and synthetic spectra computed with lte_codes
• Atomic Data : Restricted linelists for use with lte_codes
• Spectral Atlases
  • ehe_stars: A collection of UV and optical spectra of hydrogen-deficient stars and related objects
  • salt_dr1: The SALT survey of helium-rich hot subdwarfs – first data release: reduced, merged and normalised spectra.

Software

• Stellar Atmospheres Software : Overview
• Lectures : Lectures, examples and software tarballs given in Kunming and Beijing, 2019
• LTE-CODES   a package for the analysis of stellar atmospheres, especially for early-type chemically-peculiar stars.
  • STERNE : Numerical models for stellar atmospheres in local and thermodynamic equilibrium
  • SPECTRUM :  Synthetic spectra, line profiles and chemical abundances
  • SFIT : Multi-parameter optimisation for stellar spectra
• IDL programs including
  • FAST : Fourier analysis of spectroscopic time series
  • IDLINES : Stellar spectra and model fits with line identifications
• CCP7 : software from Collaborative Computational Project No. 7: The analysis of astronomical spectra