2017A&A...600A..73C


Query : 2017A&A...600A..73C

2017A&A...600A..73C - Astronomy and Astrophysics, volume 600A, 73-73 (2017/4-1)

Pulsating low-mass white dwarfs in the frame of new evolutionary sequences. IV. The secular rate of period change.

CALCAFERRO L.M., CORSICO A.H. and ALTHAUS L.G.

Abstract (from CDS):

Context. An increasing number of low-mass (M*/M☉_≤0.45) and extremely low-mass (ELM, M*/M≤0.18-0.20) white-dwarf stars are being discovered in the field of the Milky Way. Some of these stars exhibit long-period g-mode pulsations, and are called ELMV variable stars. Also, some low-mass pre-white dwarf stars show short-period p-mode (and likely radial-mode) photometric variations, and are designated as pre-ELMV variable stars. The existence of these new classes of pulsating white dwarfs and pre-white dwarfs opens the prospect of exploring the binary formation channels of these low-mass white dwarfs through asteroseismology.
Aims. We aim to present a theoretical assessment of the expected temporal rates of change of periods (dΠ/dt) for such stars, based on fully evolutionary low-mass He-core white dwarf and pre-white dwarf models.
Methods. Our analysis is based on a large set of adiabatic periods of radial and nonradial pulsation modes computed on a suite of low-mass He-core white dwarf and pre-white dwarf models with masses ranging from 0.1554 to 0.4352M, which were derived by computing the non-conservative evolution of a binary system consisting of an initially 1M ZAMS star and a 1.4M neutron star companion.
Results. We computed the secular rates of period change of radial (l=0) and nonradial (l=1,2) g and p modes for stellar models representative of ELMV and pre-ELMV stars, as well as for stellar objects that are evolving just before the occurrence of CNO flashes at the early cooling branches. We find that the theoretically expected magnitude of dΠ/dt of g modes for pre-ELMVs is by far larger than for ELMVs. In turn, dΠ/dt of g modes for models evolving before the occurrence of CNO flashes are larger than the maximum values of the rates of period change predicted for pre-ELMV stars. Regarding p and radial modes, we find that the larger absolute values of dΠ/dt correspond to pre-ELMV models.
Conclusions. We conclude that any eventual measurement of a rate of period change for a given pulsating low-mass pre-white dwarf or white dwarf star could shed light about its evolutionary status. Also, in view of the systematic difficulties in the spectroscopic classification of stars of the ELM Survey, an eventual measurement of dΠ/dt could help to confirm that a given pulsating star is an authentic low-mass white dwarf and not a star from another stellar population.

Abstract Copyright: © ESO, 2017

Journal keyword(s): asteroseismology - stars: oscillations - white dwarfs - stars: evolution - stars: interiors - stars: variables: general - stars: variables: general

CDS comments: Fig. J0756, J1458, J1628, J1730 not identified (incomplete format)

Simbad objects: 20

goto Full paper

goto View the references in ADS

Number of rows : 20
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 SDSS J011100.63+001807.1 WD* 01 11 00.6333109704 +00 18 07.059676176   18.85       DA 25 0
2 PG 0122+200 WD* 01 25 22.5121704552 +20 17 56.963079924   16.2   16.9   DOZ.7 109 0
3 V* ZZ Cet WD* 01 36 13.6153974672 -11 20 32.632874601   14.328 14.16 14.4   DA4.0 275 0
4 1SWASP J024743.37-251549.2 EB* 02 47 43.37 -25 15 49.2           ~ 42 1
5 V* RY LMi WD* 09 24 15.2482279632 +35 16 51.401570556   15.72   15.99   DA4 260 0
6 SDSS J111215.82+111745.0 WD* 11 12 15.8349560304 +11 17 45.120382836   16.54 16.31 16.2   DA 27 0
7 SDSS J114155.56+385003.0 WD* 11 41 55.5597679320 +38 50 03.088472928           D 17 0
8 SDSS J115734.45+054645.4 WD* 11 57 34.4574153336 +05 46 45.560960292   19.9   19.9   D 11 0
9 V* GW Vir WD* 12 01 45.9731868264 -03 45 40.628670300   14.87 15.04     DOQZ1 478 0
10 V* EM UMa WD* 13 53 09.9687043752 +48 40 21.171407268   16.5   17.0   DB2 96 0
11 PB 4146 ** 13 55 12.343 +19 56 45.64   16.1   16.18   D 8 0
12 V* MY Aps WD* 14 33 07.6366196272 -81 20 14.128475593   13.49 13.35 13.65   DA4.1 130 0
13 SDSS J151826.68+065813.2 WD* 15 18 26.6907090120 +06 58 13.261800468           DA 26 0
14 SDSS J161431.28+191219.4 WD* 16 14 31.2888356856 +19 12 19.463673528       16.30   DA 15 0
15 SDSS J161831.69+385415.1 WD* 16 18 31.6892114904 +38 54 15.221514960   20.0   20.1   DA 9 0
16 SDSS J173521.69+213440.6 WD* 17 35 21.6921885552 +21 34 40.607372784   16.18 16.19     D 6 0
17 PSR J1738+0333 Psr 17 38 53.96317 +03 33 10.8390           ~ 137 1
18 SDSS J184037.78+642312.3 WD* 18 40 37.7911925616 +64 23 12.272542224   18.6   19.4   DA 32 0
19 SDSS J213905.27+222709.1 * 21 39 05.2796618280 +22 27 09.206081640           ~ 3 0
20 SDSS J222859.93+362359.6 WD* 22 28 59.9311926768 +36 23 59.634736656   16.9   16.7   DA 16 0

To bookmark this query, right click on this link: simbad:objects in 2017A&A...600A..73C and select 'bookmark this link' or equivalent in the popup menu


2023.01.27-11:44:25

© Université de Strasbourg/CNRS

    • Contact