Arcturus: My School Year Hourglass
As summer comes to an end I look forward to a change in the weather, football season, hockey season, and seeing who will reign as the winner of the World Series. Even more important to me is the start of the school year. While it is more “work” than “school”, it is still that time for me to refocus on leaving behind eight weeks of vacation and setting goals for myself, the teachers, and the students for the next ten months. Just looking ahead, once I get past a choppy schedule in September, I’ll see Halloween candy on display in the pharmacy, be shopping for the holidays, and making plans for Thanksgiving. Soon we will be able to enjoy those cool, crisp October and November evenings that bring good seeing conditions to a bright New York City – way better than the humid, cloudy, and rainy summer that we had.
One thing I always remember about my summer vacation as a kid was looking out of my west facing bedroom window before going to bed. Each night I noticed that the Sun would set earlier and earlier and this twinkling star would be out there setting earlier and earlier as well. While I would see this twinkling star low in the west at almost midnight after watching two episodes of the Honeymooners on TV in early July, the setting of that star by 9pm in early September meant that it was time to get to bed earlier as the new school year was approaching – depressing at best. Now that life has made me wiser, I now know that the star I was looking at as a kid is named Arcturus. While I could just load up this article with data that anyone could find online anyway, I would like to point out a few things and maybe change your thinking about this star.
Located about 37 light years from Earth, Arcturus is classified as a Red Giant on the Hertzsprung-Russell Diagram. Sadly, the classification of our “Bear Guardian” as a Red Giant is the “beginning of the end” for a star, giving it not much time before it becomes a predicted white dwarf. Some might refer to Arcturus as Alpha Bootis due to it being the brightest star in the constellation Bootes. It should also be noted as one of the brighter stars that we can see in our hemisphere. Interestingly, while we place so much emphasis on finding the Summer Triangle (Altair, Deneb, and Vega) and Winter Triangle (Sirius, Betelgeuse, and Procyon) during the year, the Spring Triangle is also something noteworthy as it contains Spica, Regulus (or Denebola depending upon who you ask), and my “school year hourglass”, Arcturus. Even better, it is one of the stars that make up the “Diamond of Virgo” (Spica, Denebola, Cor Caroli, and Arcturus). While it is about ten percent more massive than our Sun, it greatly out sizes the Sun by about 25 times, appropriate for a Red Giant.
While Arcturus does not have a detected substellar companion as of yet, it does have my undivided attention from the end of June until the beginning of September each year. Besides being a great help in finding M3 and M5, it was very helpful in helping me make a wish each night before going to bed as a child and is still helpful in reminding me that it is soon time to get back to work. Give it a few more years and Arcturus will be there to remind me that others will be returning to the school building in September while I get to sleep until 8am – definitely something to look forward to.