We introduce a Newtonian model for the deformations of a compressible neutron star that goes beyond the widely used Cowling approximation. We employ this model to study the role played by the adiabatic index in the calculation of rotation-induced deformations: we assume a polytropic equation of state for the matter at chemical equilibrium but, since the equilibration reactions may be slow, the perturbations with respect to the unstressed configuration are modeled by using an equation of state with a different polytropic index. Hence, we quantify the impact of this departure of the adiabatic index on the calculated stresses and strains. We obtain that a small variation in the adiabatic index which regulates the perturbation can cause large variations in the calculated displacements and strains, the effect being larger for lighter stars. As a first practical application of our model, we calculate the strain developed between consecutive glitches in the Vela pulsar, confirming the difficulty that arises when trying to explain the trigger of pulsar glitches with starquakes: in order for the quake to be a possible trigger, the solid crust must never fully relax after a glitch, making the sequence of starquakes in a neutron star an history-dependent process.
Modelling strains and stresses in continuously stratified rotating neutron stars / E. Giliberti, G. Cambiotti, M. Antonelli, P.M. Pizzochero. - In: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY. - ISSN 1365-2966. - 491:1(2020 Jan), pp. 1064-1078.
|Titolo:||Modelling strains and stresses in continuously stratified rotating neutron stars|
GILIBERTI, ELIA (Primo) (Corresponding)
CAMBIOTTI, GABRIELE (Secondo)
ANTONELLI, MARCO (Penultimo) (Corresponding)
PIZZOCHERO, PIERRE MASSIMO (Ultimo)
|Parole Chiave:||astro-ph.HE; astro-ph.HE|
|Settore Scientifico Disciplinare:||Settore FIS/05 - Astronomia e Astrofisica|
Settore GEO/10 - Geofisica della Terra Solida
|Data di pubblicazione:||gen-2020|
|Data ahead of print / Data di stampa:||23-set-2018|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1093/mnras/stz3099|
|Appare nelle tipologie:||01 - Articolo su periodico|