close binary system
râžmân-e dorin-e kip
Fr.: système binaire serré
A → binary system in which the distance separating the stars is comparable to their size. Most close binaries are spectroscopic binaries (→ spectroscopic binary) and/or eclipsing binaries (→ eclipsing binary). In most of them → mass transfer occurs at some stage, an event which profoundly affects the → stellar evolution of the components. The evolution of close binaries depends on the → initial masses of the two stars and their → separation. When the more massive star evolves into a → red giant first, material will spill through the inner point onto its companion, thereby affecting its companion's evolution. Mass transfer can also alter the separation and → orbital period of the binary star.
compact binary star system
râžmân-e dorin-e hampak
Fr.: système binaire compact
A binary star system which is composed of a collapsed object
(→ degenerate dwarf, → neutron star,
or → black hole) in orbit with a low-mass (≤ 0.5 Msol)
secondary star, wherein the collapsed star → accretes
matter from its → companion.
These two objects form a binary system of overall dimensions
106 km with an orbital period of only hours or less.
→ X-ray binary.
Fr.: binaire de contact
1) A → binary star system in which the two
→ components are so close that they exchange gases
in a complex manner. Their overlapping
→ gravitational fields form a "peanut" shaped
→ equipotential surface.
double-degenerate binary system
râžmân-e dorin-e dobâr vâgen
Fr.: système binaire doublement dégénéré
A system of evolved → binary stars in which both → components have ejected their envelopes and evolve toward → white dwarf stage. So far a half dozen double-degenerate → binary systems are known, for example Henize 2-248 (M. Santander-Garcia et al., 2015, 518, 5).
Fr.: binaire à double raies
double-lined eclipsing binary
dorin-e gerefti-ye doxatté
Fr.: binaire à éclipse à double raies
double-lined spectroscopic binary
dorin-e doxatte-ye binâbnemâyik
Fr.: binaire spectroscopique à double raies
Same as → double-lined binary.
Fr.: binaire à éclipses
A binary star in which one of the two stars passes in front of the other so that the system's total light periodically fades. The most famous eclipsing binary is → Algol.
Fr.: binaire dur
In → stellar dynamics studies of → three-body encounters, a → binary system whose → binding energy far exceeds the → kinetic energy of the relative motion of an incoming third body. In such an encounter, a hard binary is likely to get harder and transfer energy to the incoming star, whereas a → soft binary is likely to be disrupted.
high-mass X-ray binary (HMXB)
dorin-e partow-e iks-e por-jerm
Fr.: binaire X de forte masse
A member of one of the two main classes of → X-ray binary systems where one of the components is a neutron star or a black hole and the other one a → massive star. HMXBs emit relatively → hard X-rays and usually show regular pulsations, no X-ray bursts, and often X-ray eclipses. Their X-ray luminosity is much larger than their optical luminosity. In our Galaxy HMXBs are found predominantly in the → spiral arms and within the → Galactic disk in young → stellar populations less than 107 years old. One of the most famous HMXB is Cygnus X-1 which was the first stellar-mass black hole discovered. See also: → low-mass X-ray binary.
Fr.: binaire en interaction
low-mass X-ray binary (LMXB)
dorin-e partow-e iks-e kam-jerm
Fr.: binaire X de faible masse
A member of one of the two main classes of
→ X-ray binary systems where one of the components is a
→ neutron star or → black hole
and the other component a → low-mass star with a spectral type A
or later. LMXBs mainly emit → soft X-rays.
The ratio of their optical to X-ray luminosities is less than 0.1. They belong
to → old stellar populations
with ages 5-15 × 109 years and are found in
→ globular clusters
and in the → bulge
of our → Milky Way
galaxy; some are also found in the disk.
Hercules X-1 is an example of LMXBs.
magnetic cataclysmic binary
dorin-e gatluri-ye meqnâtisi
Fr.: binaire cataclysmique magnétique
A cataclysmic binary in which the white dwarf primary has a strong magnetic field that radically affects the accretion flow in the system. → polar
massive close binary
dorin-e kip-e porjerm
Fr.: binaire serrée massive
neutron star binary system
râžmân-e dorin-e setârehâ-ye noroni
Fr.: système binaire d'étoiles à neutron
dorin-e šidsanjik, ~ nursanjik
Fr.: binaire photométrique
A binary star whose binarity is detectable from its variability and light-curve that has certain specific characteristics.
pre-main sequence binary
dorin-e piš-rešte-ye farist
Fr.: binaire pré-séquence principale Markarian's Chain
Fr.: binaire SB1
Same as → single-lined binary.
Fr.: binaire SB2
Same as → double-lined binary.
Fr.: bianire semi-détachée
A binary system whose secondary member fills its Roche lobe but whose primary member does not.