August 11-15, 2014


White Dwarf Luminosity Function from PanSTARRS

Marco Lam (University of Edinburgh)

Nigel Hambly (University of Edinburgh)

Main sequence (MS) stars with less than ~8 solar masses will end up as white dwarfs (WDs) at the end point of their evolution. This mass range encompasses the vast majority of stars in the Galaxy. Thus, WD, a degenerate core left behind from its progenitor, is the most common end-point of stellar evolution. Nuclear burning is negligible at this stage, and gravitational contraction does not provide an appreciable amount of energy, so WDs cannot replenish the energy they radiate away. Hence, the luminosity and temperature decrease monotonically with time. The small and compact nature of WD gives rise to a high density, large surface gravity and low luminosity. The use of reduced proper motion (RPM) as a proxy-distance can cleanly separate the WDs from the MS in certain RPM-colour space, similar to a colour-magnitude diagram where the WDs are a few magnitudes dimmer than the MS due to their low intrinsic luminosities. It is only possible in this high speed imaging digital era to scan through the sky rapidly and probe to faint levels, greatly increasing the survey volume in which to search for very low luminosity objects. It has been proven to be an efficient way to identify WD candidates. In the poster section, I will update the current status of the “Prospects for Cool WD Science from PanSTARRS” using the most recently available data from the three year 3-pi Steradian Survey.

Mode of presentation: poster