https://doi.org/10.1140/epjp/s13360-024-05072-8
Regular Article
Accretion disk in the Hartle–Thorne spacetime
1
National Nanotechnology Laboratory of Open Type, Al-Farabi av. 71, 050040, Almaty, Kazakhstan
2
Al-Farabi Kazakh National University, Al-Farabi av. 71, 050040, Almaty, Kazakhstan
3
Institute of Nuclear Physics, Ibragimova, 1, 050032, Almaty, Kazakhstan
4
International Engineering Technological University, Al-Farabi av. 93 G/5, 050060, Almaty, Kazakhstan
5
Scuola di Scienze e Tecnologie, Divisione di Fisica, Università di Camerino, Via Madonna delle Carceri 9, 62032, Camerino, Italy
6
SUNY Polytechnic Institute, 13502 Utica, 10001, New York, USA
7
Istituto Nazionale di Fisica Nucleare, Sezione di Perugia, Via Alessandro Pascoli, 23c, 06123, Perugia, Italy
8
INAF - Osservatorio Astronomico di Brera, Via Brera 28, 20121, Milano, Italy
9
Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Cto. Exterior S/N, C.U., Coyoacán, 34000, Mexico, Mexico
10
Dipartimento di Fisica and ICRA, Università di Roma “La Sapienza”, Città Universitaria di Roma - Sapienza, Piazzale Aldo Moro, 2, 00185, Roma, Italy
Received:
12
January
2024
Accepted:
7
March
2024
Published online:
20
March
2024
We consider the circular motion of test particles in the gravitational field of a rotating deformed object described by the Hartle–Thorne metric. This metric represents an approximate solution to the vacuum Einstein field equations, accurate to second order in the angular momentum J and to first order in the mass quadrupole moment Q. We calculate the orbital parameters of neutral test particles on circular orbits (in accretion disks) such as angular velocity, 
, total energy, E, angular momentum, L, and radius of the innermost stable circular orbit, 
, as functions of the total mass, M, spin parameter, 
and quadrupole parameter, 
, of the source. We use the Novikov-Thorne-Page thin accretion disk model to investigate the characteristics of the disk. In particular, we analyze in detail the radiative flux, differential luminosity, and spectral luminosity of the accretion disk, which are the quantities that can be measured experimentally. We compare our results with those obtained in the literature for the Schwarzschild and Kerr metrics and the q-metric. It turns out that the Hartle–Thorne metric and the Kerr metric lead to similar results for the predicted flux and the differential and spectral luminosities, whereas the q-metric predicts different values. We compare the predicted values of M, j, and q with those of realistic neutron star models. Furthermore, we compare the values of with the static and rotating radii of neutron stars.
Talgar Konysbayev, Yergali Kurmanov, Orlando Luongo, Marco Muccino, Hernando Quevedo, Ainur Urazalina have contributed equally to this work.
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© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2024. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
