Binary Star Systems and Clusters:

What is a binary star system?

A star system that consists of two stars orbiting a common center of mass.

What are wide binaries in binary star systems?

Stars that have orbits that keep them spread apart from one another, evolving separately with little impact from each other.

What are close binaries in binary star systems?

Stars that evolve nearby and influence each other, sometimes transferring mass.

What is a visible binary?

A pair of stars far enough apart that both can be viewed through a telescope or binoculars.

Define eclipsing binary stars.

Two stars whose orbits are at an angle so that one passes in front of the other from Earth's perspective, causing an eclipse.

How do spectroscopic binary stars appear to observers?

Stars in the binary appear to be close, and scientists must measure the light's wavelengths to detect their binary nature based on spectral lines.

What is an astrometric binary?

A star that seems to exhibit movement due to the gravitational influence of an unseen companion.

What distinguishes optical binaries from actual binary systems?

Appear to be binary systems because they are near each other in the line of sight but do not orbit one another.

What are two types of star clusters?

Open clusters and globular clusters.

Why are star clusters important to astronomers?

They allow astronomers to study and model stellar evolution and the ages of stars since they share a common origin and distance.

Describe an open cluster.

A group of loosely bound stars that formed from the same giant molecular cloud, usually containing a few hundred stars and found in the galaxy's spiral arms.

What are globular clusters?

Tightly packed spherical systems containing thousands to a million stars, known to be some of the oldest stars in the galaxy.

What characterizes stars in globular clusters?

Population II stars, with very low amounts of metals and older ages, typically between 10-12 billion years.

In what region of the galaxy are globular clusters typically found?

In the halo region outside the disk of the galaxy, rather than in the gassy and dusty disk.