Geodetic Precession and Pulse Profile Changes Over Time of Pulsar B1913+16

Sparrow Roch, “Geodetic Precession and Pulse Profile Changes Over Time of Pulsar B1913+16”
Mentors: Joseph Swiggum & David Kaplan, Physics

Pulsars are dense and quickly rotating neutron stars that emit radiation from their magnetic poles. A pulsar’s magnetic axis is offset from its spin axis, so for those emitting towards Earth, we observe a regular, repeating “pulse” as the pulsar spins. Ten percent of known pulsars orbit binary companions and this work focuses on the first discovered binary pulsar: B1913+16. Observations of this star confirmed predictions of orbital decay due to gravitational wave emissions, which earned the discovery team, Joseph Taylor and Russell Hulse, the Nobel Prize in Physics in 1993. In July/August 2019, we observed PSR B1913+16 daily over the course of two weeks with the Arecibo Observatory. Collected data is based on observed times of arrivals of pulses over a range of radio wavelengths. Of particular note is that the star’s unique pulse profile has been changing over time. Comparing this new data with earlier observations (1985-2016) allows for further information about the geodetic precession, or wobble, of B1913+16 over time. Analyzing the changes in B1913+16’s pulse profile shape allows for more accurate modeling of the star’s emission beam and a greater understanding of its orbital behavior in its dynamic system.


  1. Hello!

    My name is Sparrow Roch. I am a second year student studying Physics and Computer Science. This project combines two great joys: stars and programming. Like many others, I’m fascinated with the so many different objects that can be found in space! In my opinion, pulsars are especially interesting because many of their characteristics are so extreme compared to more familiar stars – they’re extraordinarily dense, quite small, and can rotate hundreds of times per second! There’s still so much that we can learn from and about pulsars, so studying them is also very exciting!

    Please feel free to leave any questions or comments below.

    Thank you for taking the time to look at my presentation!

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