scholarly journals Stability in the most external region of the Oort Cloud: evolution of the ejected comets

2019 ◽  
Vol 490 (2) ◽  
pp. 2495-2506
Author(s):  
J A Correa-Otto ◽  
M F Calandra
Keyword(s):  
Binary Stars ◽  
Outer Boundary ◽  
Oort Cloud ◽  
Dynamical Behaviour ◽  
Dynamical Structure ◽  
Wide Binary ◽  
External Region ◽  
Test Particles ◽  
The Galaxy ◽  
Galactic Tide

ABSTRACTIn this paper, we present a study of the dynamical effects of the Galaxy on the external region of the Oort Cloud. The aims of this paper are: (i) to determine an outer limit for the Oort Cloud; and (ii) to analyse the dynamical behaviour of the most external objects of the Oort Cloud and how they are ejected from the Solar system. To achieve these aims, we follow the temporal evolution of massless test particles in the Galactic environment of the solar neighbourhood. We show that the effect of the perturbations from the Galactic tide in the particles is similar to that found for the evolution of the population of wide binary stars. Moreover, in the Oort Cloud, we find a dynamical structure around 105 au conformed by objects unbound from the Sun. This structure allows us to define a transition region of stability and an outer boundary for the Oort Cloud, and it is also in agreement with previous results about the disruption of wide binary stars.

Mass Ratios in Wide Binary Stars

1997 ◽  
Vol 485 (2) ◽  
pp. 785-788 ◽  
Author(s):  
Mauri J. Valtonen
Keyword(s):  
Binary Stars ◽  
Wide Binary ◽  
Mass Ratios

A pas de trois birth for wide binary stars

Nature ◽  
2012 ◽  
Vol 492 (7428) ◽  
pp. 191-192
Author(s):  
Keivan Guadalupe Stassun
Keyword(s):  
Binary Stars ◽  
Wide Binary

scholarly journals Supportive Evidence for a Brown Dwarf Solar Companion

2004 ◽  
Vol 202 ◽  
pp. 214-216
Author(s):  
John J. Matese
Keyword(s):  
Solar System ◽  
Oort Cloud ◽  
Evidence Based ◽  
Supportive Evidence ◽  
Orbital Elements ◽  
Brown Dwarf ◽  
Wide Binary ◽  
Gas Giant ◽  
Binary Object

We have previously given evidence based on Oort cloud comet orbital elements which suggested that there may be a Jovian-mass brown dwarf in our solar system. An extended cometary database is now available. The analyses have been repeated and we find that the set of statistically significant correlated anomalies is enhanced. We also respond to unsupported objections that have been raised to this conjecture. If real, the wide-binary object would constitute a natural dynamical intermediary between gas giant planetary objects and isolated objects.

scholarly journals Waves and Oscillations in the Non-Magnetic Photosphere

1990 ◽  
Vol 138 ◽  
pp. 217-228 ◽  
Author(s):  
Franz - Ludwig Deubner
Keyword(s):  
Direct Observation ◽  
Outer Boundary ◽  
Dynamical Behaviour ◽  
Solar Photosphere ◽  
Complex Patterns

The solar photosphere is the outer boundary of the cavity which defines the spectrum of the global p-modes. It is also the lowest layer that permits direct observation of the boiling mixture of motions which eventually create the complex patterns apparent in the chromosphere and corona. Studies of the dynamical behaviour of this layer are therefore of paramount importance for an overall understanding of the dynamic sun.

scholarly journals Binary stars on the galaxy SFH

2015 ◽  
Vol 11 (S315) ◽  
Author(s):  
F. Zhang ◽  
L. Li ◽  
Z. Han
Keyword(s):  
Star Formation ◽  
Binary Stars ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Star Formation History ◽  
Population Synthesis ◽  
Feedback Process ◽  
Formation History ◽  
The Galaxy ◽  
Degeneracy Problem

AbstractUsing the Yunnan-II evolutionary population synthesis models comprising binary stars, we find that the inclusion of binary stars can raise the derived stellar metallicity Z* and/or age t (degeneracy problem), raise the stellar mass M*, lower the gaseous metallicity Zgas and star formation rate (SFR) of galaxies. This means that a few stars form recently in galaxies, while more stars form during the entire evolution process when considering binary stars. If the degeneracy between t and Z* can be broken, its effect on the feedback process and star formation history can be determined.

scholarly journals Numerical Simulations of Star Formation Bursts Induced by the Galaxy-Galaxy Interaction

1987 ◽  
Vol 115 ◽  
pp. 650-653
Author(s):  
Masafumi Noguchi ◽  
Shiro Ishibashi
Keyword(s):  
Star Formation ◽  
Kinetic Energy ◽  
Supernova Explosion ◽  
Particle Model ◽  
Disk Galaxies ◽  
Triggering Mechanism ◽  
Cloud Particle ◽  
Test Particles ◽  
Galaxy Interaction ◽  
The Galaxy

The galaxy-galaxy interaction has been proposed as a possible triggering mechanism of the star formation bursts in some galaxies (e.g. Larson and Tinsley 1978). To investigate the nature of star formation bursts triggered by interaction we have numerically simulated close encounters between disk galaxies, taking the star formation process into account (see Noguchi and Ishibashi 1986 for details). We used the cloud-particle model, in which gas clouds move as test particles in the gravitational field of the galaxies. When two clouds collide with each other, an OB-star is formed. The cloud system loses its kinetic energy by inelastic cloud-cloud collisions. The supernova explosion which follows the formation of an OB-star provides kinetic energy to the nearby clouds.

scholarly journals Stars and gas in the most metal-poor galaxies – I. COS and MUSE observations of SBS 0335−052E

2020 ◽  
Vol 500 (3) ◽  
pp. 2908-2927
Author(s):  
Aida Wofford ◽  
Alba Vidal-García ◽  
Anna Feltre ◽  
Jacopo Chevallard ◽  
Stéphane Charlot ◽  
...  
Keyword(s):  
Star Formation ◽  
Binary Stars ◽  
Spectral Synthesis ◽  
Optical Emission ◽  
Rotating Stars ◽  
Test Models ◽  
The Galaxy ◽  
Low Metallicity ◽  
Super Star Clusters ◽  
Shock Precursor

ABSTRACT Among the nearest most metal-poor starburst-dwarf galaxies known, SBS 0335−052E is the most luminous in integrated nebular He ii λ4686 emission. This makes it a unique target to test spectral synthesis models and spectral interpretation tools of the kind that will be used to interpret future rest-frame UV observations of primeval galaxies. Previous attempts to reproduce its He ii λ4686 luminosity found that X-ray sources, shocks, and single Wolf–Rayet stars are not main contributors to the He ii-ionizing budget; and that only metal-free single rotating stars or binary stars with a top-heavy IMF and an unphysically low metallicity can reproduce it. We present new UV (COS) and optical (MUSE) spectra that integrate the light of four super star clusters in SBS 0335−052E. Nebular He ii, [C iii], C iii], C iv, and O iii] UV emission lines with equivalent widths between 1.7 and 5 Å and a C iv λλ1548, 1551 P-Cygni like profile are detected. Recent extremely metal-poor shock + precursor models and binary models fail to reproduce the observed optical emission-line ratios. We use different sets of UV and optical observables to test models of constant star formation with single non-rotating stars that account for very massive stars as blueshifted O v λ1371 absorption is present. Simultaneously fitting the fluxes of all high-ionization UV lines requires an unphysically low metallicity. Fitting the P-Cygni like + nebular components of C iv λλ1548, 1551 does not constrain the stellar metallicity and time since the beginning of star formation. We obtain 12+log(O/H)$\, = 7.45\pm 0.04$ and log(C/O)$\, = -0.45^{+0.03}_{-0.04}$ for the galaxy. Model testing would benefit from higher spatial resolution UV and optical spectroscopy of the galaxy.

Sign in / Sign up

Export Citation Format

Share Document