Orsola De Marco is an Italian and Australian astrophysicist whose research concerns interacting binary stars and planetary nebulae. She is a professor in the School of Mathematical and Physical Sciences and Astrophysics and Space Technologies Research Centre at Macquarie University in Sydney.
De Marco's research on old stars concerns the formation of planetary nebulae, binary stars that become large and close enough for their envelopes to interact, post common envelope binaries, and the role of binary interactions in planetary nebulae.
She was the lead researcher for one of the first five images released from the James Webb Space Telescope, of the planetary nebula NGC 3132. She and her coauthors used this image to reconstruct the formation of this nebula from a nova, including the unexpected discovery of multiple companion stars that were involved in this event.
As well as studying these systems observationally, her work has also included the development of supercomputer simulations of colliding stars.
After attending the liceo scientifico in Bologna, and earning an International Baccalaureate, De Marco studied astrophysics at University College London in England, finishing with first class honours in 1994. She continued at University College London for a PhD jointly supervised by Michael J. Barlow and Peter Storey, which she completed in 1997, with the dissertation Cool Wolf-Rayet central stars and their planetary nebulae.
After postdoctoral research at ETH Zurich in Switzerland from 1997 to 1999, University College London from 1999 to 2000, and the American Museum of Natural History in the US from 2000 to 2009, she became an associate professor at Macquarie University in 2009. She was named as an ARC Future Fellow in 2013 and since 2015 has been full professor.