Archive for January 2, 2020

01/02/2020 – Ephemeris – Orion’s great red star Betelgeuse is dimming

January 2, 2020 Comments off

Ephemeris for Thursday, January 2nd. The Sun will rise at 8:20. It’ll be up for 8 hours and 53 minutes, setting at 5:13. The Moon, at first quarter today, will set at 12:48 tomorrow morning.

The bright red giant star in the constellation Orion’s shoulder is in the news. It is dimming, and it is dimmer now than it has been for a very long time. A chart by the American Association of Variable Star Observers shows that this is the dimmest it’s been going back to 1970 and maybe a long time before that. Betelgeuse was first noticed to vary in brightness in 1838. It is the left star at the top of Orion’s upright rectangle of stars. Bellatrix is the right corner star. Betelgeuse is now only a little brighter than it, and much dimmer than Rigel the lower right corner star. A couple of years ago it was brighter than it had been since 1970. Astronomers are watching and waiting. They expect Betelgeuse to explode as a supernova sometime in the next million years.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.


Orion's brightest stars

Orion’s brightest stars with their names for 9 p.m. January 7. Click on the image to make Orion a giant hunter. Created using Stellarium, which shows Betelgeuse at its average magnitude of 0.45.

Orion and Betelgeuse

Orion and Betelgeuse on Christmas night 2019 by David Dickinson. Photo from a smart phone from Virginia Beach. Note that Betelgeuse is not much brighter than Bellatrix and much dimmer than Rigel.

Magnitude estimates of Betelgeuse

Magnitude estimates of Betelgeuse since 1970. Credit AAVSO.

Note on the magnitude scale:  The lower the magnitude the brighter the star.  Stars with magnitudes less than 1.5 are first magnitude stars.  Second magnitude stars are between 1.5 and 2.5, and so on.

For more information check out Universe Today:

And Dr. Phil Plait’s Bad Astronomy:

Categories: Ephemeris Program, Stars Tags: