Introduction to Astrophysics
Instructor-
Golam Dastegir Al-Quaderi
Professor
Department of Physics, DU
1
, Binary Systems
• Binary System: A binary system is a system of two
astronomical bodies which are close enough such that
their gravitational attraction causes them to orbit
each other around a barycenter.
• .
Orbit for two bodies with the same mass but with Orbit for two bodies with slightly
eccentric elliptic orbits, common for binary stars Unequal masses, like Pluto and Charon
2
, Binary Systems
• Barycenter: In astronomy, the barycenter (from
Ancient Greek βαρύς (barús) “heavy”, and κέντρον
(kéntron) “center”) is the center of mass of two or
more bodies, about which the bodies orbit.
• A barycenter is a dynamical point, not a physical
object.
• Binary Stars: A binary star is a system of two stars
that are gravitationally bound to and are in orbit
around each other.
3
, Binary Systems
• Binary stars in the night sky, that are seen as a
single object to the naked eye are often resolved
using a telescope as separate stars (visual binary).
• More than “four-fifths” of all “stars” in the sky
are actually multiple systems, two or more stars
in orbit about a common center of mass.
• The most common of the multiple star systems
are binary stars, systems of only two stars
together.
4
Instructor-
Golam Dastegir Al-Quaderi
Professor
Department of Physics, DU
1
, Binary Systems
• Binary System: A binary system is a system of two
astronomical bodies which are close enough such that
their gravitational attraction causes them to orbit
each other around a barycenter.
• .
Orbit for two bodies with the same mass but with Orbit for two bodies with slightly
eccentric elliptic orbits, common for binary stars Unequal masses, like Pluto and Charon
2
, Binary Systems
• Barycenter: In astronomy, the barycenter (from
Ancient Greek βαρύς (barús) “heavy”, and κέντρον
(kéntron) “center”) is the center of mass of two or
more bodies, about which the bodies orbit.
• A barycenter is a dynamical point, not a physical
object.
• Binary Stars: A binary star is a system of two stars
that are gravitationally bound to and are in orbit
around each other.
3
, Binary Systems
• Binary stars in the night sky, that are seen as a
single object to the naked eye are often resolved
using a telescope as separate stars (visual binary).
• More than “four-fifths” of all “stars” in the sky
are actually multiple systems, two or more stars
in orbit about a common center of mass.
• The most common of the multiple star systems
are binary stars, systems of only two stars
together.
4
