2014A&A...571A..45I


Query : 2014A&A...571A..45I

2014A&A...571A..45I - Astronomy and Astrophysics, volume 571A, 45-45 (2014/11-1)

The formation of low-mass helium white dwarfs orbiting pulsars. Evolution of low-mass X-ray binaries below the bifurcation period.

ISTRATE A.G., TAURIS T.M. and LANGER N.

Abstract (from CDS):

Millisecond pulsars (MSPs) are generally believed to be old neutron stars (NSs) that have been spun up to high rotation rates via accretion of matter from a companion star in a low-mass X-ray binary (LMXB). This scenario has been strongly supported by various pieces of observational evidence. However, many details of this recycling scenario remain to be understood. Here we investigate binary evolution in close LMXBs to study the formation of radio MSPs with low-mass helium white dwarf companions (He WDs) in tight binaries with orbital periods Porb≃2-9h. In particular, we examine i) if the observed systems can be reproduced by theoretical modelling using standard prescriptions of orbital angular momentum losses (i.e. with respect to the nature and the strength of magnetic braking), ii) if our computations of the Roche-lobe detachments can match the observed orbital periods, and iii) if the correlation between WD mass and orbital period (MWD, Porb) is valid for systems with Porb <2days. Numerical calculations with a detailed stellar evolution code were used to trace the mass-transfer phase in ∼400 close LMXB systems with different initial values of donor star mass, NS mass, orbital period, and the so-called γ-index of magnetic braking. Subsequently, we followed the orbital and the interior evolution of the detached low-mass (proto) He WDs, including stages with residual shell hydrogen burning. We find that severe fine-tuning is necessary to reproduce the observed MSPs in tight binaries with He WD companions of mass <0.20M, which suggests that something needs to be modified or is missing in the standard input physics of LMXB modelling.
Result. from previous independent studies support this conclusion. We demonstrate that the theoretically calculated (MWD, Porb)-relation is in general also valid for systems with Porb<2-days, although with a large scatter in He WD masses between 0.15-0.20M. The results of the thermal evolution of the (proto) He WDs are reported in a follow-up paper (Paper II).

Abstract Copyright:

Journal keyword(s): binaries: close - Sun: evolution - stars: neutron - white dwarfs - X-rays: binaries - accretion, accretion disks

Simbad objects: 12

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Number of rows : 12
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 PSR J0024-7204Y Psr 00 24 01.4016 -72 04 41.837           ~ 18 1
2 PSR J0023-72U Psr 00 24 09.8325 -72 03 59.667           ~ 50 2
3 PSR J0348+0432 Psr 03 48 43.6363173480 +04 32 11.461921260           ~ 204 1
4 PSR J0751+1807 Psr 07 51 09.1539 +18 07 38.335           ~ 264 1
5 PSR J1012+5307 Psr 10 12 33.4345449600 +53 07 02.548542576     19.5     DA 336 1
6 PSR J1641+3627D Psr 16 41 41.0 +36 27 37           ~ 9 0
7 PSR J1738+0333 Psr 17 38 53.96317 +03 33 10.8390           ~ 132 1
8 PSR J1748-2446M Psr 17 48 04.622 -24 46 40.77           ~ 12 0
9 PSR J1748-2446V Psr 17 48 05.102 -24 46 34.49           ~ 13 0
10 PSR J1816+4510 Psr 18 16 35.9314 +45 10 33.864           ~ 76 0
11 PSR J1910-5959A Psr 19 11 42.7562 -59 58 26.900 22.02 22.13 22.03     DA5 82 1
12 PSR J1915+1606 Psr 19 15 27.99999 +16 06 27.4034     22.5     ~ 951 1

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2022.05.24-10:53:58

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