Astronomy and Astrophysics - An Introductory Survey, A lecture series by Prof. G. Srinivasan - Lecture 24 - Binary Neutron Stars

In 1974, a binary neutron star system was discovered - two neutron stars going around a common centre of mass. Russel Hulse, a young PhD student working under the supervision of Joseph Taylor, had been at the centre of this discovery which gave us the first evidence (albeit indirect) of Gravitational Waves! This lecture describes neutron star binaries of different types and their significance for Einstein's General Theory of Relativity. ABOUT THE LECTURE In 1974, a binary neutron star system was discovered - two neutron stars going around a common centre of mass. This raised the following question: ""How did such a system form?"" The first part of this lecture is devoted to the evolution of massive stars in 'binary systems, and the eventual formation of a bound pair of neutron stars. The separation of the two neutron stars was a mere million kilometres, roughly the radius of the Sun. With two massive objects in such a tight binary, General Relativistic effects were expected to be large in comparison to the GR effects, say, on the orbit of Mercury. Indeed they were! The second part of this lecture will describe the various relativistic effects that were verified to unprecedented accuracy using this system. Observations of this system also provided the very first evidence for Gravitational Radiation. Not surprisingly, the Nobel Prize was awarded to Hulse and Taylor, who discovered this pulsar and demonstrated the existence of gravitational radiation. Lecture 25: Recycled Pulsars Lecture 26: Radio Galaxies ABOUT THE LECTURE SERIES This lecture series is organized by the Astronomical Society of India as a part of its Golden Jubilee celebrations. Aimed at undergraduate and graduate students, this series of talks by renowned astrophysicist and teacher, Prof G. Srinivasan, starts from the first principles of Physics and builds up the subject rigorously to the present state of our understanding. Series website: https://astron-soc.in/srini-ana The website hosts a question bank as well as a list of suggested readings for each lecture (prepared by Dr Sushan Konar) ABOUT THE SPEAKER Professor G. Srinivasan In a research career spanning more than five decades, his interests have spanned many aspects of physics and astrophysics. He is a passionate teacher and has authored two outstanding Astronomy texts titled ‘What Are The Stars?’ and ‘Can Stars Find Peace?’ He is a Past President of the Astronomical Society of India, and a Past President of the Division on Space and High Energy Astrophysics of the International Astronomical Union. In his distinguished career he has worked at the University of Chicago, USA; the IBM Research Laboratory in Zurich, Switzerland; Chalmers University of Technology, Goteborg, Sweden; the Cavendish Laboratory, University of Cambridge, England and the Raman Research Institute, Bengaluru Follow us on social media at https://twitter.com/asipoec https://www.facebook.com/asi.poec/ This series is also supported by the IAU OAE Centre in India https://twitter.com/astro4edu_India https://www.facebook.com/OAE-Center-India-105698322030674