Planet Hunters Talk

background info on light curves

  • broder_fisk by broder_fisk

    It would be interesting to have a list with examples of what different light curve types mean. Yes, there are explanations on some of them, such as the cepheid, flares, "heartbeatstar" etc, but there are more types of patterns that often occur. Such as this, what kind of star makes this kind of curve?
    http://talk.planethunters.org/#/subjects/APH0000gee?quarter=1-2
    Also a curve that looks like shark/saw teeth, what does that mean?
    http://talk.planethunters.org/#/subjects/APH0000d1r
    I've seen them a few times but don't know how to tag them.
    I know a little about star types, but I can't tie it to what I see on the screen. It would be helpful to have more insight into what I'm actually looking at.

    Also:
    What kind of light curve would our sun produce?
    And:
    I've noticed that "quiet" stars are comparatively rare; most of them seem to vary a lot in brightness.

    Posted

  • davidbundy77 by davidbundy77

    It helps to look at the vertical scale, because Planet Hunters automatically adjusts the scale so that the brightest and dimmest data points fit on the graph. The scale can vary enormously. Quiet stars have variations of about 0.0001 which is probably just instrument noise. Other stars have enormous changes in brightness of over 0.1 (that is 10%!) in just a few days.

    Your first example shows what can go wrong with the scale. There is one negative data point at day 36.4. This is a result of poor data processing, but unfortunately it causes the scale to stretch ridiculously so all the other points are plotted on a line at the top. It is impossible to view the lightcurve properly on Planet Hunters and the interface doesn't allow the user to change the scale manually 😦. Hopefully someone will eventually get around to tidying up the data so this doesn't happen.

    Posted

  • davidbundy77 by davidbundy77

    Title: The Sun as a Variable Star
    Authors: Albrecet, R., Maitzen, H. M., & Rakos, K. D.
    Journal: Astronomy and Astrophysics, Vol. 3, p. 236 (1969)
    Bibliographic Code: 1969A&A.....3..236A

    http://adsabs.harvard.edu/full/1969A%26A.....3..236A

    Posted

  • broder_fisk by broder_fisk

    Thanks 😃

    Posted