L. P. Singh
Articles written in Journal of Astrophysics and Astronomy
Volume 18 Issue 1 June 1997 pp 15-21
Massive compact dwarf stars and C-field
The effect of C-field in high density matter has been studied. We find that the negative energy and negative pressure of the C-field helps in formation of massive compact stable neutron stars of mass ∼ 0.5 solar mass which is in the range of 0.01 to 1.0 solar mass of recently observed dwarf stars.
Volume 35 Issue 1 March 2014 pp 97-106 General Editorial on Publication Ethics
Evolution of Primordial Black Holes in Loop Quantum Cosmology
D. Dwivedee B. Nayak M. Jamil L. P. Singh R. Myrzakulov
In this work, we study the evolution of primordial black holes within the context of loop quantum cosmology. First we calculate the scale factor and energy density of the Universe for different cosmic era and then taking these as inputs, we study evolution of primordial black holes. From our estimation it is found that accretion of radiation does not affect evolution of primordial black holes in loop quantum cosmology. We also conclude that due to slow variation of scale factor, the upper bound on initial mass fraction of presently evaporating PBHs are much greater in loop quantum cosmology than the standard case.
Volume 44 All articles Published: 20 May 2023 Article ID 0049
Evolution of weak discontinuity waves in non-ideal interstellar environments
SHWETA RAHUL KUMAR CHATURVEDI SHOBHIT KUMAR SRIVASTAVA L. P. SINGH
A systematic method is used to study the problem of propagation of planar, cylindrically symmetric and spherically symmetric shockwaves of the one-dimensional motion of an inviscid, self-gravitating, non-ideal interstellar gas cloud. The analytic solution of the problem is resolved, which specifies non-linear behavior in the physical plane. The transport equation, which describes the evolution of weak discontinuity in non-ideal gas is derived. It is observed that the nature of the solution completely depends on the net volumetric cooling rate and self-gravitating parameter. It is observed that an increase in the value of self-gravitating parameter resultsin delay of process of shock formation and shock forms early when heating dominates cooling in the system. Also, expansive waves take less time to decay in planar geometry as compared to cylindrical and spherical geometries and compressive waves take more time to develop shocks for cylindrical and spherical geometriesas compared to planar geometry.
Volume 44, 2023
Continuous Article Publishing mode
Since January 2016, the Journal of Astrophysics and Astronomy has moved to Continuous Article Publishing (CAP) mode. This means that each accepted article is being published immediately online with DOI and article citation ID with starting page number 1. Articles are also visible in Web of Science immediately. All these have helped shorten the publication time and have improved the visibility of the articles.
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