These things shouldn't happen: stable stars don't show sudden leaps in temperature. But that's exactly what Arcturus is doing. Arcturus is the huge red giant in the constellation Bootes, second brightest star in the night sky, and -- according to some UFO encounter reports -- home to some alleged extraterrestrials.
The most recently derived temperature measurement for Arcturus is about 300 degrees hotter than the 4300 degrees Kelvin astronomers have banked on for the past two decades. It's tempting to dismiss the increase as a measurement error -- and indeed there's some suggestion that it is -- except for one startling trend.
In a letter published in a recent issue of the British astronomy journal, The Observatory, Oxford astronomer Elizabeth Griffin reveals that the latest high temperature measurement "falls exactly in line" with the general upward trend in temperature displayed by Arcturus over the past 70 years. The earliest readings for Arcturus began at about 3900 degrees Kelvin in the late 1920s, rose to about 4100 degrees in the late 1960s, and then averaged about 4300 degrees in the 1970s.
So what's going on? We turned to astrophysicist David Strickland, editor of The Observer for enlightenment. "I think that generally stars don't do much of their evolution on a human timescale," he replied in an email interview." (Unless it's the exploding stage at the end of their lives), although some of the more massive ones do move around a bit temperature-wise over the course of a few years. However, in the case of Arcturus this is unlikely, which made Dr. Griffin's letter of interest."
Concludes Griffin: "Either astrophysicists are getting steadily nearer to, or further from, astrophysical reality, or Arcturus is heating up for some evolution of its own."
--Patrick Huyghe
Arcturus is the brightest star in the Bootes constellation