Think Pink For Spring – Arcturus Is Back!

This map shows the sky around 10 p.m. local time in facing east tonight Feb. 24. Arcturus, the brightest star in the constellation Bootes the Herdsman, is well below the Big Dipper. The nearly full moon joins the scene a short distance from Leo’s brightest star Regulus. Maps created with Stellarium

I was startled two nights ago when I turned down the road and spied pink Arcturus scintillating low in the eastern sky. With snow all around and more on the way, my psyche was steeped in winter. So what was this big, bright spring star doing staring me in the face?

Find Arcturus using the old adage “Arc to Arcturus” by sliding down the arc of the Big Dipper’s handle.

After the sun, Arcturus is the 4th brightest star in the sky. It pokes up around 10 o’clock in late February. You’ll find it with ease simply by following the curve of the Big Dipper’s handle downward toward the eastern horizon. Its name comes from the ancient Greek word “arktos” for bear and means “Guardian of the Bear”. Appropriate considering it rides herd on Ursa Major the Great Bear, the brightest part of which is the Big Dipper.

The calendar notwithstanding, Arcturus is a true “spring star”. Come May, when the first mosquitos begin to whine, you’ll find it perched high in the southern sky lording over the landscape much as Orion does now during the early evening hours.

Right now the Bear Watcher is hunkered down in the east, sparking through tree branches and over neighborhood rooftops. Twinkling, most obvious in the brighter stars, is caused by shifting air currents that are more pronounced at lower altitudes.

Arcturus, an orange giant star some 21 million miles in diameter, compared to the sun, Jupiter and other familiar stars.

Funny that the atmosphere can jiggle the light of such a massive star about as if it were as flighty a thing as a dandelion seed. Arcturus is an orange giant star 25 times larger than the sun, but all that girth is reduced to a trembling point of light 36 light years (216 trillion miles) from Earth. Its true brilliance is likewise masked by distance. Put in place of the sun, Arcturus would dazzle 113 times brighter and cover an area of sky half as big as the Big Dipper. As for color, it looks pinkish to my eye. Others see it as red-orange.

Watch this flush-faced star loft higher and higher in the east in the coming weeks with the return of the spring season. There’s a special bonus if you go out tonight. The moon, on its way to becoming the Full Snow Moon tomorrow night, will shine near Leo the Lion’s brightest star Regulus.

7 Responses

  1. Mike

    This startled my wife and I on Saturday night as well! We felt it was flashing red / green like a plane or a drone but it did not seem to move as we were driving. Why does this star “twinkle” so much Bob? When we got to our destination I got out the binos and took a look. It still was very “flashy”. Much more than atmospherics. Thanks. Hope you are well. Are we likely to get some strong auroras from the sunspots? Take care.

    1. astrobob

      Hi Mike,
      It twinkles so much partly because it’s so bright and easy to see twinkle (all stars do but our eyes aren’t sensitive enough to pick it up on the fainter ones) and because of low altitude (we look through a ton more air at the bottom, thickest part of the atmosphere). It’s also possible that the air was particularly unstable that night. Unlikely to get any auroras from the recent spots – they were too far off to the west side of the sun’s disk.

  2. Giorgio Rizzarelli

    I try again again.. I suspect Facebook links are blocked by some antispam system…
    Here’s a small article by myself about the voting of names for Pluto’s new moons (deadline today at noon). Replace each “(dot)” word with a dot.

      1. astrobob

        Giorgio – PS. Thanks for the inspiration! When I saw Vulcan in the lead I just had to write my own take on the contest.

  3. Todd

    My daughter needs answer to this question. “I drive the Great Bear with my staff. Look for me in the summer sky. Arcturus is my brightest star.”

    1. astrobob

      I hate to give the answer to this question only because I’d take away from the pleasure your daughter will have finding it herself. Instead, here’s clue. Have her type “Arcturus constellation” in Google. That will give her her answer.

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