scholarly journals Neutron Star Formation in Theoretical Supernovae — Low Mass Stars and White Dwarfs —

1987 ◽  
Vol 125 ◽  
pp. 281-303
Author(s):  
Ken'ichi Nomoto
Keyword(s):  
Neutron Stars ◽  
White Dwarfs ◽  
Binary Systems ◽  
Crab Nebula ◽  
Close Binary ◽  
Low Mass Stars ◽  
Supernova Explosions ◽  
Low Mass ◽  
Strongly Degenerate ◽  
The Crab Nebula

The presupernova evolution of stars that form semi-degenerate or strongly degenerate O+Ne+Mg cores is discussed. For the 10–13 M⊙ stars, behavior of off-center neon flashes is crucial. The 8–10 M⊙ stars do not ignite neon and eventually collapse due to electron captures. Properties of supernova explosions and neutron stars expected from these low mass progenitors are compared with the Crab nebula. We also examine the conditions for which neutron stars form from accretion-induced collapse of white dwarfs in close binary systems.

scholarly journals The ESO supernovae type Ia progenitor survey (SPY)

2020 ◽  
Vol 638 ◽  
pp. A131 ◽  
Author(s):  
R. Napiwotzki ◽  
C. A. Karl ◽  
T. Lisker ◽  
S. Catalán ◽  
H. Drechsel ◽  
...  
Keyword(s):  
Radial Velocity ◽  
White Dwarfs ◽  
Binary Systems ◽  
Detection Efficiency ◽  
Close Binary ◽  
The Galaxy ◽  
Type Ia ◽  
Low Mass ◽  
Kinematic Studies ◽  
Ia Supernovae

Close double degenerate binaries are one of the favoured progenitor channels for type Ia supernovae, but it is unclear how many suitable systems there are in the Galaxy. We report results of a large radial velocity survey for double degenerate (DD) binaries using the UVES spectrograph at the ESO VLT (ESO SN Ia Progenitor surveY – SPY). Exposures taken at different epochs are checked for radial velocity shifts indicating close binary systems. We observed 689 targets classified as DA white dwarfs (displaying hydrogen-rich atmospheres), of which 46 were found to possess a cool companion. We measured radial velocities (RV) of the remaining 643 DA white dwarfs. We managed to secure observations at two or more epochs for 625 targets, supplemented by eleven objects meeting our selection criteria from literature. The data reduction and analysis methods applied to the survey data are described in detail. The sample contains 39 double degenerate binaries, only four of which were previously known. Twenty are double-lined systems, in which features from both components are visible, the other 19 are single-lined binaries. We provide absolute RVs transformed to the heliocentric system suitable for kinematic studies. Our sample is large enough to sub-divide by mass: 16 out of 44 low mass targets (≤0.45 M⊙) are detected as DDs, while just 23 of the remaining 567 targets with multiple spectra and mass > 0.45 M⊙ are double. The detected fraction amongst the low mass objects (36.4 ± 7.3%) is significantly higher than for the higher-mass, carbon-oxygen core dominated part of the sample (3.9 ± 0.8%), but it is much lower than expected from the detection efficiency for companion masses of 0.05 M⊙ or higher and a 100% binary fraction. This suggests either companion stars of with a mass below 0.05 M⊙ or some of the low mass white dwarfs are single.

scholarly journals Explosions of Helium Stars and Type IB/IC/IIB Supernovae

1991 ◽  
Vol 143 ◽  
pp. 515-528 ◽  
Author(s):  
K. Nomoto
Keyword(s):  
Binary Systems ◽  
Theoretical Models ◽  
Light Curves ◽  
Close Binary ◽  
Star Models ◽  
Helium Stars ◽  
Fast Decline ◽  
Supernova Explosions ◽  
Low Mass ◽  
Helium Star

Theoretical models of supernova explosions of helium stars with various masses are reviewed to examine possible connections between Wolf-Rayet stars and Type Ib/Ic/IIb supernovae. Nucleosynthesis, Rayleigh-Taylor instabilities, and light curves are compared with observations. Maximum brightness and the fast decline of the light curves of typical SNe Ib/Ic can be well accounted for by the helium star models if the helium star mass is as low as 3-5 M⊙. These low mass helium stars can form from stars of 12-18 M⊙ after Roche-lobe overflow in close binary systems. Probably progenitors of typical SNe Ib/Ic are not classified as Wolf-Rayet stars.

scholarly journals Pulsars and Close Binary Systems

1971 ◽  
Vol 46 ◽  
pp. 273-278
Author(s):  
Virginia Trimble ◽  
Martin Rees
Keyword(s):  
Mass Transfer ◽  
Neutron Stars ◽  
Binary Systems ◽  
Alternative Explanation ◽  
Galactic Plane ◽  
Orbital Motion ◽  
Close Binary ◽  
Close Binaries ◽  
Close Binary Systems ◽  
Supernova Explosions

It is first considered what must happen if pulsars (i.e. neutron stars) are formed in close binary systems (CBS), and whether the resulting orbital motion and mass transfer should be observable. As this set of alternatives seems unlikely, there follow suggestions of how one might prevent the formation of neutron stars in close binaries. Finally, it is shown that ‘runaway’ pulsars with velocities larger than about 15 km/sec cannot be produced by isotropic supernova explosions within close binaries, and an alternative explanation is suggested for the observed correlation of periods of pulsars with their distances from the galactic plane.

Do neutron stars produce jets?

1986 ◽  
Vol 64 (4) ◽  
pp. 474-478 ◽  
Author(s):  
Eric D. Feigelson
Keyword(s):  
Neutron Star ◽  
Neutron Stars ◽  
Supernova Remnants ◽  
Binary Systems ◽  
Crab Nebula ◽  
Compact Object ◽  
Radio Pulsars ◽  
X Ray ◽  
The Crab Nebula ◽  
X Ray Binaries

The evidence for jets emanating from neutron stars is reviewed. Isolated radio pulsars do not appear to produce collimated outflows. A few supernova remnants, notably the Crab nebula, exhibit jetlike protrusions at their outer boundaries. These are probably "blowouts" of the plasma in the remnant rather than true jets from a neutron star. However, several cases of degenerate stars in X-ray binary systems do make jets. SS433 has twin precessing jets moving outward at v ~ 0.26c, and Sco X-1 has radio lobes with v ~ 0.0001c. Cyg X-3 appears to eject synchrotron plasmoids at high velocities. Other X-ray binaries associated with variable radio sources are discussed; some are interesting candidates for collimated outflow. G109.1-1.0 is an X-ray binary in a supernova remnant that may have radio or X-ray jets. It is not clear in all these cases, however, that the compact object is a neutron star and not a black hole or white dwarf.A tentative conclusion is reached that isolated neutron stars do not produce jets, but degenerate stars in accreting binary systems can. This suggests that the presence of an accretion disk, rather than the characteristics of an isolated pulsar's dipole magnetosphere, is critical in making collimated outflows.

Close binary systems among very low-mass stars and brown dwarfs

2005 ◽  
Vol 326 (10) ◽  
pp. 944-947 ◽  
Author(s):  
R. D. Jeffries ◽  
P. F. L. Maxted
Keyword(s):  
Binary Systems ◽  
Brown Dwarfs ◽  
Close Binary ◽  
Low Mass Stars ◽  
Close Binary Systems ◽  
Low Mass

scholarly journals The EBLM Project

2019 ◽  
Vol 625 ◽  
pp. A150 ◽  
Author(s):  
Alexander von Boetticher ◽  
Amaury H. M. J. Triaud ◽  
Didier Queloz ◽  
Sam Gill ◽  
Pierre F. L. Maxted ◽  
...  
Keyword(s):  
Physical Properties ◽  
Stellar Evolution ◽  
Binary Systems ◽  
Close Binary ◽  
Low Mass Stars ◽  
Orbital Parameters ◽  
Eclipse Observations ◽  
Low Mass ◽  
Orbital Periods ◽  
Host Stars

Measurements of the physical properties of stars at the lower end of the main sequence are scarce. In this context we report masses, radii and surface gravities of ten very-low-mass stars in eclipsing binary systems, with orbital periods of the order of several days. The objects probe the stellar mass-radius relation in the fully convective regime, M⋆ ≲ 0.35 M⊙, down to the hydrogen burning mass-limit, MHB ∼ 0.07 M⊙. The stars were detected by the WASP survey for transiting extra-solar planets, as low-mass, eclipsing companions orbiting more massive, F- and G-type host stars. We use eclipse observations of the host stars, performed with the TRAPPIST, Leonhard Euler and SPECULOOS telescopes, and radial velocities of the host stars obtained with the CORALIE spectrograph, to determine the physical properties of the low-mass companions. Surface gravities of the low-mass companions are derived from the eclipse and orbital parameters of each system. Spectroscopic measurements of the host star effective temperature and metallicity are used to infer the host star mass and age from stellar evolution models for solar-type stars. Masses and radii of the low-mass companions are then derived from the eclipse and orbital parameters of the binary systems. The objects are compared to stellar evolution models for low-mass stars, to test for an effect of the stellar metallicity and orbital period on the radius of low-mass stars in close binary systems. Measurements are found to be in good agreement with stellar evolution models; a systematic inflation of the radius of low-mass stars with respect to model predictions is limited to 1.6 ± 1.2%, in the fully convective low-mass regime. The sample of ten objects indicates a scaling of the radius of low-mass stars with the host star metallicity. No correlation between stellar radii and the orbital periods of the binary systems is determined. A combined analysis with thirteen comparable objects from the literature is consistent with this result.

scholarly journals Microquasars and ULXS: Fossils of GRB Sources

2004 ◽  
Vol 194 ◽  
pp. 14-17 ◽  
Author(s):  
I. F. Mirabell
Keyword(s):  
Black Holes ◽  
Neutron Stars ◽  
Binary Systems ◽  
Gamma Ray ◽  
Massive Stars ◽  
Compact Objects ◽  
Primary Star ◽  
Long Duration ◽  
Supernova Explosions ◽  
Low Mass

AbstractGamma-ray bursts (GRBs) of long duration probably result from the core-collapse of massive stars in binary systems. After the collapse of the primary star the binary system may remain bound leaving a microquasar or ULX source as remnant. In this context, microquasars and ULXs are fossils of GRB sources and should contain physical and astrophysical clues on their GRB-source progenitors. Here I show that the identification of the birth place of microquasars can provide constrains on the progenitor stars of compact objects, and that the runaway velocity can be used to constrain the energy in the explosion of massive stars that leave neutron stars and black holes. The observations show that the neutron star binaries LS 5039, LSI +61°303 and the low-mass black hole GRO J1655-40 formed in energetic supernova explosions, whereas the black holes of larger masses (M ≥ 10 M⊙) in Cygnus X-l and GRS 1915+105 formed promptly, in the dark or in underluminous supornovao. The association with clusters of massive stars of the microquasar LSI +61°303 and the magnetars SGR 1806-20 and SGR 1900+14, suggest that very massive stars (M ≥ 50 M⊙) may -in some cases- leave neutron stars rather than black holes. The models of GRB sources of long duration have the same basic ingredients as microquasars and ULXs: compact objects with accretion disks and relativistic jets in binary systems. Therefore, the analogies between microquasars and AGN may be extended to the sources of GRBs.

Neutron stars and cosmic-ray production

1968 ◽  
Vol 46 (10) ◽  
pp. S472-S475 ◽  
Author(s):  
D. B. Melrose ◽  
A. G. W. Cameron
Keyword(s):  
Neutron Stars ◽  
Supernova Remnants ◽  
Gamma Ray ◽  
Crab Nebula ◽  
Cosmic Ray ◽  
X Rays ◽  
Strong Point ◽  
Electrons And Ions ◽  
Supernova Explosions ◽  
The Crab Nebula

Recent investigations of the properties of neutron stars and of supernova explosions indicate that neutron stars should frequently be formed as supernova remnants. It now appears unlikely that any form of internal energy storage can play an important role in the production of X rays or cosmic rays. If mass infall onto a neutron star occurs at the upper limiting value allowed by radiation stresses, instabilities are likely to make the resulting mass infall, X-ray, gamma-ray, and cosmic-ray production very intermittent. It is shown that such a model may be able to account for many features of the Crab nebula: the energy input in electrons and ions, the character of the fast-moving light ripples or wisps, and the strong point source of ~50 MHz radiation.

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