# Oscillation Modes of Strange Quark Stars with a Strangelet Crust

## TL;DR

This paper investigates the oscillation modes of strange quark stars with a strangelet crust, revealing slight frequency increases due to the crust and highlighting limitations of Newtonian gravity in modeling such stars.

## Contribution

It introduces a two-component equation of state for strange quark stars with a strangelet crust and analyzes their non-radial oscillation modes using the Cowling approximation.

## Key findings

- Strangelet crust slightly increases spheroidal mode frequencies.
- Newtonian gravity overestimates mode frequencies for strange stars.
- Comparison with neutron stars and bare strange stars highlights differences.

## Abstract

We study the non-radial oscillation modes of strange quark stars with a homogeneous core and a crust made of strangelets. Using a 2-component equation of state (core+crust) for strange quark stars that can produce stars as heavy as 2 solar masses, we identify the high-frequency l=2 spheroidal (f, p) in Newtonian gravity, using the Cowling approximation. The results are compared to the case of homogeneous compact stars such as polytropic neutron stars, as well as bare strange stars. We find that the strangelet crust only increases very slightly the frequency of the spheroidal modes, and that Newtonian gravity overestimates the mode frequencies of the strange star, as is the case for neutron stars.