Skip to main content Accessibility help
×
Hostname: page-component-848d4c4894-xm8r8 Total loading time: 0 Render date: 2024-06-14T18:11:38.121Z Has data issue: false hasContentIssue false

6 - Getting started with Cepheids

Published online by Cambridge University Press:  22 September 2009

Get access

Summary

Just to get an idea of what variable star observing is all about, here are two active, easily found stars that we will observe informally, before we know too much. The first is Delta Cephei, an ideal star to begin with for several reasons. It is part of a bright and compact star group, it is usually around magnitude 4, and it is an active star, always offering something interesting for you to watch.

Delta Cephei's variation was discovered by John Goodricke in 1784 (see chapter 30), and it is the star for which all the Cepheid variables are named. The variation in this giant star is small but extremely regular with a period of several days. It is also typical that this star enjoys a leisurely decline to minimum that is followed by a rapid rise to maximum.

At maximum, Delta Cephei is easily visible at magnitude 3.5, and at minimum it shines at 4.4. If you observe every night or two you will soon see how it falls, then rises, week after week.

Notice the two stars Zeta and Epsilon on Fig. 6.1 and in the sky. Which is brighter? Let us give Zeta Cephei an arbitrary value of “1” and Epsilon a value of “5”. Each night estimate the brightness of Delta Cephei as follows:

  1. 1 — as bright as Zeta

  2. 2 — slightly fainter than Zeta

  3. 3 — halfway between Zeta and Epsilon

  4. 4 — slightly brighter than Epsilon

Type
Chapter
Information
Observing Variable Stars
A Guide for the Beginner
, pp. 20 - 24
Publisher: Cambridge University Press
Print publication year: 1989

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Save book to Kindle

To save this book to your Kindle, first ensure coreplatform@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.

Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

Find out more about the Kindle Personal Document Service.

Available formats
×

Save book to Dropbox

To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.

Available formats
×

Save book to Google Drive

To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.

Available formats
×