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Thirty Minute Talking Science: Thursday 22nd February, 12 noon (PDT) - Jeff Cummings


Announcing the next talk of the TMTS series (Thirty Minutes for Talking Science)

Dr. Jeff Cummings (STSCI, JHU) - White Dwarfs in Star Clusters: The Initial-Final Mass Relation for Stars from 0.85 to 8 Solar Masses

Thursday 22nd February, 12 noon (PDT), TMT Project Office Board Room

Requests for remote participation by Zoom to Warren Skidmore (

Talk Abstract: The spectroscopic study of white dwarfs provides both their mass and cooling age, the time since they have evolved from the tip of the asymptotic giant branch.  For a white dwarf that is a star cluster member, comparison of its cooling age to the total cluster's age gives the evolutionary timescale of its progenitor star, and hence the mass.  This initial-final mass relation (IFMR) provides valuable information on how a progenitor star evolves and loses mass throughout its lifetime, and how this changes with progenitor mass.  Our work presents a uniform analysis of 85 white dwarfs spanning from progenitor masses of 0.85 to 8 solar masses.  Comparison of our work to theoretical IFMRs shows consistency in their shapes, but there remains a systematic offset and a moderate dispersion that cannot be explained by errors.  I will discuss possible explanations for this, including the effects of composition and rotation on stellar evolution.  I will also discuss the difficulties involved in spectroscopically characterizing these faint targets in star cluster, and how TMT will be able to address many of the remaining challenges in the IFMR.