Birth: 14 May 1955
Death: 03 Feb 2016
Links to a few of their papers:
Mercedes was born in Jamaica and obtained a BSc in Physics from the University of the West Indies. She later moved to Toronto to pursue an MSc in Space Science and then a PhD where she focussed on imaging binary star systems. 
She went on to become a Professor of Astronomy at the University of Virginia and Penn State. In her research into binary star systems, she modelled the accretion of mass between the two bodies. She was the first in astronomy to apply the technique of tomography (using X-rays to image a cross section through a solid object). Her work also focused on simulating the gas transfer between the stars within a binary system and using this to predict the consequential magnetic activity. 
She credits her pursuing a physics degree to her friends and teachers, who were all women as her primary and secondary education were segregated by gender. She has been quoted discussing the importance of those role models to her “Having those female teachers gave me a boost,” “As a young woman I could say, ‘Hey, I can be like them.’” She also committed a lot of time to mentoring and encouraging young people in physics, especially those from underrepresented groups.