Learning Goals: Students will learn how the changing light from an eclipsing binary star system can reveal information about the individual stars and their orbits.

Jan 17, 2018 Binary stars are two stars orbiting a common center of mass. More than four-fifths of the single points of light we observe in the night sky are actually two or more stars orbiting together. Algol is a spectroscopic binary where the primary star is a blue B8-class star 3.5 times more massive than our sun, with a surface temperature of 12 500 K and a diameter 3 times that of the sun. The second star is a K2-class star with a diameter of 3.5 more than our sun, a surface temperature of 4 500 Kelvin and a mass of about 0.8 M Sun.

Suggested Observations: time-delay series of images of a known eclipsing binary star system timed during subsequent minima (the dimmest point in the lightcurve) e.g.: AB And, BU Vul, XZ And

Challenge:

Find the period and relative luminosities of the components of an eclipsing binary star system. Observe an eclipsing binary and make a measurement of its period.

Resources: Worksheet

Terminology:binary star, lightcurve, minimum

Demos from UNL: Eclipsing Binary

Tutorials: Importing Images into MaxIm, Photometry in Maxim

Background:

A binary star is a star system consisting of two stars orbiting around their common center of mass. The brighter star is called the primary and the other is its companion star, or secondary. Research between the early 19th century and today suggests that many stars are part of either binary star systems or star systems with more than two stars, called multiple star systems. The term double star may be used synonymously with binary star, but more generally, a double star may be either a binary star or an optical double star which consists of two stars with no physical connection but which appear close together in the sky as seen from the Earth. A double star may be determined to be optical if its components have sufficiently different proper motions or radial velocities, or if parallax measurements reveal its two components to be at sufficiently different distances from the Earth. Most known double stars have not yet been determined to be either bound binary star systems or optical doubles.

Binary star systems are very important in astrophysics because calculations of their orbits allow the masses of their component stars to be directly determined, which in turn allows other stellar parameters, such as radius and density, to be indirectly estimated. This also determines an empirical mass-luminosity relationship (MLR) from which the masses of single stars can be estimated.

Binary stars are often detected optically, in which case they are called visual binaries. Many visual binaries have long orbital periods of several centuries or millennia and therefore have orbits which are uncertain or poorly known. Brother opus 141 manual online. They may also be detected by indirect techniques, such as spectroscopy (spectroscopic binaries) or astrometry (astrometric binaries). If a binary star happens to orbit in a plane along our line of sight, its components will eclipse and transit each other; these pairs are called eclipsing binaries, or, as they are detected by their changes in brightness during eclipses and transits, photometric binaries.

Binary Star Music Group