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Theory

The Parallax Formula

The parallax formula states that the distance to a star is equal to 1 divided by the parallax angle,P,where P is measured in arc-seconds, and d is parsecs.

Parallax is a method of using two points of observation to measure the distance to an object by observing how it appears to move against a background. Parallax is a method of using two points of observation to measure the distance to an object by observing how it appears to move against a background. In astronomy, the distances to other stars is too great to measure using two objects on the Earth's surface.

The Linear Regression

Linear regression is a linear model, e.g. a model that assumes a linear relationship between the input variables (x) and the single output variable (y). More specifically, that y can be calculated from a linear combination of the input variables (x)

The Chepheid Variable Star

A Cepheid or Cepheid variable is a particular class of variable star, the brightness of the quals varies periodically.

A light curve is a graph that shows the brightness of an object over a period of time. In the study of objects that change their brightness over time such as novae, supernovae, and variable stars, the light curve is a simple, but valuable tool to a scientist.

Eclipsing Binary Stars

You can find data related to the star brightness, and then make a graphic with that data. Comparing both stars you will be able to find out which one is brighter, and then found their distance and radius.

The Exoplanet Transit Method

The transit method is a photometric method that aims to indirectly detect the presence of one or more exoplanets in orbit around a star. In 1999, the method was used to confirm the existence of HD209458b, a planet that had been discovered almost at the same time by the radial velocity method.

Doppler Spectroscopy

Doppler spectroscopy is used to detect the periodic velocity shift of the stellar spectrum caused by an orbiting giant planet. (This method is also referred to as the radial velocity method.)