vsots
EX Hydrae
Meet EX Hydrae
RY Sagittarii
Rebels With a Cause?
If there is a single word that one would use to describe the R Coronae Borealis (RCB) variable stars, it is enigmatic. This small, puzzling class of stars are most peculiar. With just under 50 known RCB stars, they appear to belong to an elite gang of rebellious variables. While we have been trained to think that activity of a star generally occurs as the star brightens, RCB stars prefer to do just the opposite.
R Coronae Borealis
Prepared by Kate Davis, AAVSO Technical Assistant, Web - January 2000
The Enigmatic R Coronae Borealis...
Mu Cephei
Z Ursae Majoris
Prepared by Kate Davis, AAVSO Technical Assistant, Web - March 2000
EU Delphini
EU Delphini and the Small-Amplitude Pulsating Red Giants
Pulsating Red Giant Stars
As stars like the sun approach the ends of their lives, and begin to run out of fuel, they expand and cool, and become red giant stars. During this stage, they become unstable and begin to pulsate -- at first with a very small amplitude, but eventually with a very large amplitude.
Alpha Orionis (Betelgeuse)
Note: This page was edited to modify the magnitudes of comparison stars Procyon (0.5 to 0.4 V) and Aldebaran (1.1 to 0.9 V) and to add the link to the chart available via the AAVSO's 10-Star Tutorial. - Elizabeth O. Waagen, 6 January 2020
V725 Sagittarii
The Remarkable Transformation of V725 Sgr
Introduction
W Hydrae
Near the tail end of the expansive constellation of Hydra the sea serpent resides the bright southern semiregular-type variable star W Hydrae. The period of W Hya is just shy of a year at 361 days. Based on over 3,400 observations in the AAVSO International Database, the variable has a magnitude range of 5.7-10.0, making W Hya a great star for observers with binoculars and/or small telescopes who can observe to -28 degrees declination.