A new class of unstable modes of a rotating relativistic star

Andersson, Nils (1998) A new class of unstable modes of a rotating relativistic star The Astrophysical Journal, 502, (2, part 1), pp. 708-713. (doi:10.1086/305919).


Full text not available from this repository.


The first numerical study of axial (toroidal) pulsation modes of a slowly rotating relativistic star is presented. The calculation includes terms of first order in ???(R3/M)1/2 « 1 (R is the radius, M is the mass, and ? is the rotation frequency of the star) and accounts for effects due to the Coriolis force. Effects due to the centrifugal flattening of the star enter at order ?2 and are not included in the analysis. It is shown that increased rotation tends to decrease the damping times for prograde modes, while retrograde modes become longer lived. Specifically, we show that rotation affects the axial gravitational wave w-modes in this way. We also present the first relativistic calculation of the so-called r-modes (analogous to Rossby waves in the Earth's oceans). These have frequencies of the same order of magnitude as the rotation frequency of the star. The presented results indicate that the r-modes are unstable due to the emission of gravitational radiation for all rotating perfect fluid stars. This is interesting, since the previously considered gravitational wave instability associated with (for example) the f-mode of the star sets in at a critical rotation rate. Because they are also unstable for the slowest rotating stars, the r-modes may well be of considerable astrophysical importance.

Item Type: Article
Digital Object Identifier (DOI): doi:10.1086/305919
ISSNs: 0004-637X (print)
Related URLs:
ePrint ID: 29423
Date :
Date Event
Date Deposited: 07 Feb 2007
Last Modified: 16 Apr 2017 22:22
Further Information:Google Scholar
URI: http://eprints.soton.ac.uk/id/eprint/29423

Actions (login required)

View Item View Item