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Why Variable Stars Are Worth Targeting

Why target variable stars? Targeting variable stars when stargazing helps improve your ability to distinguish faint objects (high on the scale of star magnitude) and increases the sensitivity of your eyes for detecting differences in brightness.

There are books on the subject, like this one by Percy. But what makes them interesting night sky targets to hone in with your home telescope is that there are many types and you can challenge yourself to find them in the pursuit of helping astronomy. Read on…

Understanding Variable Stars
Title on the subject of variable stars

available at Amazon

It’s also easier to sight variable stars than other targets in the night sky of light polluted areas such as cities. And you can become part of a bigger mission to observe variables to monitor their brightness and so add to astronomy knowledge.

Types of variable stars

Two main types: extrinsic (or external) where the brightness is due to an external driver and intrinsic (or internal) where brightness is driven internally.

Subtypes:

  • Pulsating variables, include LPVs and Cepheids.
  • Long period variables (LPVs) are Mira variables. These are red giants.
  • Cepheids are regular pulsating stars that are used as yardsticks to measure the distance to galaxies beyond the Milky Way
  • Eclipsing binaries (EB) are binary systems with equal brightness but changes in orbit creates an eclipse that reduces the brightness of one
  • Irregular variables are an assortment of random types
  • R CorBor
  • Novas are the most stand-out in that their outer layer explodes
  • Supernova are the rarest variable star and is basically the death of a star
Examples of variable stars in a classification tree
Source: CSIRO

What are examples of variable stars?

Examples of variable stars include the eclipsing variables of Algol (Beta Persei, Beta Lyrae, and BL Telescopium. A pulsating example is Delta Cephei, a Cepheid. 

  • With the naked eye there are about a dozen or so you can pick up at the right time.

The aavso.org site offers variable star lists and charts to print. For beginners, look for the Getting Started dropdown for the Manual for Visual Observing of Variable Stars.

Help monitor variable stars

American Association of Variable Star Observers (aavso.org) is the place to log your information and they have manuals to download to help you do this to advance the science of variable stars.

If this is something you would like to get into, AAVSO have a list of easy stars to begin with.

Resources

To find out more about identifying and monitoring variable stars, check out these sites:

AAVSO| Australian National Telescope Facility | Variable Stars South