Updated predictions for gravitational wave emission from tidal disruption events for next-generation observatories

¹ Dipartimento di Fisica G. Occhialini, Università degli Studi di Milano-Bicocca, Piazza della Scienza 3, 20126 Milano, Italy
² INFN, Sezione di Milano-Bicocca, Piazza della Scienza 3, I-20126 Milano, Italy
³ Leiden Observatory, Leiden University, PO Box 9513 NL-2300 RA, Leiden, The Netherlands

^⋆ Corresponding author: martina.toscani@unimib.it

Received: 23 May 2025
Accepted: 1 August 2025

Abstract

In this paper, we investigate the gravitational wave (GW) emission from stars tidally disrupted by black holes (TDEs), using a semi-analytical approach. Contrary to previous works in which this signal is modeled as a monochromatic burst, here we take into account all its harmonic components. On top of this, we also extend the analysis to a population of repeated-partial TDEs, in which the star undergoes multiple passages around the black hole before complete disruption. For both populations, we estimate the rate of individual GW detections considering future observatories such as LISA and a potential decihertz mission, and derive the GW background from these sources. Our conclusions, even if more conservative, are consistent with previous results presented in the literature. In fact, full disruptions of stars will not be seen by LISA but will be important targets for decihertz observatories. In contrast, GWs from repeated disruptions will not be detectable in the near future.