MATs (Monday Afternoon Talks), 04/10/2023 – Speakers: Lalitha Sairam (Birmingham) & Genevieve Schroeder (Northwestern)

Monday April 10, 2023 3:00 pm

MATs (Monday Afternoon Talks)

3:00pm  Lalitha Sairam, University of Birmingham

When Stars Misbehave: The Impact of Stellar Activity on Exoplanet Research and the Need for a Public Forecast Abstract

The study of exoplanets has unveiled a diverse array of worlds beyond our solar system. However, the detection and characterization of exoplanets remain challenging due to the magnetic activity of their host stars. Stellar noise produced by flares, star spots, and plages can mimic the signal of a low-mass exoplanet, leading to spurious detections and reducing the accuracy of atmospheric characterization. Although they are modelled for hindrance, stellar activity continues to affect detections by reducing the signal. In this talk, I will give an overview of the challenges that stellar activity poses for exoplanet detection and atmospheric characterisation. I will present my ongoing project, STellar ACtvity foreCAst for Optimal observations of exoplanets (STACCATO), which provides a forecasting model to predict the optimal time for exoplanet detection and atmospheric characteristics reducing the need for stellar activity mitigation. I will also demonstrate how STACCATO is synergistic with ongoing and upcoming missions such as HARPS3, ARIEL, and PLATO, and how these missions can be used in conjunction with STACCATO to further advance our understanding of exoplanets and their host stars

3:30pm   Genevieve Schroeder, Northwestern University

The Hunt for Magnetar Remnants: Searching for the Elusive Radio Signal from Binary Neutron Star Mergers

The merger of two neutron stars (NSs) is known to produce gravitational wave (GW) emission, a short gamma-ray burst (SGRB), and kilonova, and may also be responsible for the production of a massive, rapidly spinning, highly magnetized NS, known as a magnetar. If this magnetar remnant is at least temporarily stable against collapse, it will deposit a fraction of its rotational energy (up to ~10^53 erg) into the surrounding kilonova ejecta, powering a synchrotron radio signal from the interaction of the ejecta with the circumburst medium, which may be detected at late times (~years). Combining new radio observations with previous studies, I present our analysis of a survery of SGRBs and determine the fraction of SGRBs that produce stable magnetar remnants. Taking into account binary NS mergers similar to our Galactic binary NS population, like GW 170817, as well as an additional component of high-mass mergers, like GW 190425, I also place constraints on the maximum mass of a non-rotating NS.

Host: Josh Borrow


  • Lalitha Sairam, University of Birmingham
  • Genevieve Schroeder, Northwestern University

Event Contact