https://doi.org/10.1140/epjc/s10052-019-7194-5
Regular Article - Theoretical Physics
Classical and general relativistic post-Keplerian effects in binary pulsars hosting fast rotating main sequence stars
1
Ministero dell’Istruzione, dell’Università e della Ricerca (M.I.U.R.)-Istruzione, Viale Unità di Italia 68, 70125, Bari, BA, Italy
2
IRAP, Université de Toulouse, CNRS, UPS, CNES, 14, avenue Edouard Belin, 31400, Toulouse, France
3
Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Nice & 77, Chemin des Basses Moulières, 06130, Grasse, France
4
Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, UMR7293 Lagrange, 28 Av. Valrose, 06108, Nice Cedex 2, France
* e-mail: lorenzo.iorio@libero.it
Received:
8
July
2019
Accepted:
1
August
2019
Published online:
16
August
2019
We consider a binary system composed of a pulsar and a massive, fast rotating, highly distorted main sequence star of mass M, spin angular momentum 
, dimensionless mass quadrupole moment 
, equatorial and polar radii 
, flattening 
, and ellipticity 
as a potential scenario to dynamically put to the test certain post-Keplerian effects of both Newtonian and post-Newtonian nature. We numerically produce time series of the perturbations 
of the Rømer-like, orbital component of the pulsar’s time delay 
induced over 10 years by the pN gravitoelectric mass monopole 
, quadrupole 
, gravitomagnetic spin dipole 
and octupole 
accelerations along with the Newtonian quadrupolar 
one. We do not deal with the various propagation time delays due to the travelling electromagnetic waves. It turns out that, for a Be-type star with 
orbited by a pulsar with an orbital period 
40–70 days, the classical oblateness-driven effects are at the 
level, while the pN shifts are of the order of 
, depending on their orbital configuration. The root-mean-square (rms) timing residuals 
of almost all the existing non-recycled, non-millisecond pulsars orbiting massive, fast rotating main sequence stars are 
. Thus, such kind of binaries have the potential to become interesting laboratories to measure, or, at least, constrain, some Newtonian and post-Newtonian (
, and, perhaps, 
as well) key features of the distorted gravitational fields of the fast rotating stars hosted by them.
© The Author(s), 2019
