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Title: Neutron stars as laboratories for gravity physics

We study the structure of neutron stars in R+αR² gravity model with perturbative method. We obtain mass-radius relations for four representative equations of state (EoS). We find that, for |α|~10⁹ cm², the results differ substantially from the results of general relativity. The effects of modified gravity are seen as mimicking a stiff or soft EoS for neutron stars depending upon whether α is negative or positive, respectively. Some of the soft EoS that are excluded within the framework of general relativity can be reconciled for certain values of α of this order with the 2 solar mass neutron star recently observed. Indeed, if the EoS is ever established to be soft, modified gravity of the sort studied here may be required to explain neutron star masses as large as 2 M{sub ⊙}. The associated length scale √(α)~10⁵ cm is of the order of the the typical radius of neutron stars implying that this is the smallest value we could find by using neutron stars as a probe. We thus conclude that the true value of α is most likely much smaller than 10⁹ cm².
Authors:
 [1]
  1. Department of Physics, Mimar Sinan Fine Arts University, Bomonti 34380, İstanbul (Turkey)
Publication Date:
OSTI Identifier:
22306105
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1604; Journal Issue: 1; Conference: PPC 2013: 7. international conference on interconnections between particle physics and cosmology, Lead-Deadwood, SD (United States), 24 Jun - 6 Jul 2013; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Publisher:
AIP
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; EQUATIONS OF STATE; GENERAL RELATIVITY THEORY; GRAVITATION; LENGTH; MASS; NEUTRON STARS; PROBES