THE SOUTHWORTH PLANETARIUM 70 Falmouth Street Portland, Maine 04103 (207) 780-4249 usm.maine.edu/planet 43.6667° N 70.2667° W Founded January 1970 2022-2023: XCV Sunrise: 5:09 a.m. Sunset: 8:07 p.m. Civil twilight begins: 4:36 a.m. Civil twilight ends: 8:41 p.m. Sun's host constellation: Taurus the Bull Moon phase: Waxing crescent (8% illuminated) Moonrise: 6:58 a.m. Moonset: 11:34 p.m. Julian date: 2460086.29 "Every ten years you're a different person." -Martin Amis THE DAILY ASTRONOMER Monday, May 22, 2023 Not Now, Betelgeuse! Do you hear that? Listen closely. Now, do you hear it? The pulses throbbing like corpse hearts through the floorboards. The breath intakes sharp enough to disembowel diamonds. The collective sighs, moans and gasps of thousands of souls, sounding so much like a World Cup match, but without the nationalistic animosities. Do you feel it? The prickly heat sensation running current-like around the epidermis and enough unbearable tension to fill a modern-day college campus. Yes, that's right. Betelgeuse, the highly massive star marking Orion's shoulder, is at it again. By which we mean, of course, that it is exhibiting behaviours so outside the norm that some avid skywatchers expect it to explode as a Type II supernova at any moment.* Within the last two weeks, Betelgeuse has started shining fifty percent brighter than usual. While we know that Betelgeuse is a variable star and as such its brightness does vary, it hasn't shone so brilliantly so quickly before. A couple of years ago, one might recall,Betelgeuse dimmed considerably, much to the delight and chagrin of astronomers around the globe.** This atypical light reduction was thought to be a precursor to the titanic Type II eruption we've all been just dying to see. Alas, this brightness diminishment turned out to be merely the result of nearby dust obscuration, or so it was believed. Crests fell down like medicinable gum off an Arabian tree once we all realized that Orion was destined to retain his fireopal shoulder star. However, now that Betelgeuse is showing unusual variability once again, hopes have risen once more at the prospect of beholding the dazzling brilliance of a nearby Supernova. One can almost see the scopes turning in perfect unison toward this red supergiant behemoth star in eager anticipation of this blitzkrieg of a fireworks show. But wait! Betelgeuse is too close to the Sun to be seen! In fact, yesterday was Betelgeuse's heliacal setting day. By this statement we mean that last night was, well, the last night an observer would have been able to observe Betelgeuse. Now, it will be totally obscured by dusk and won't return to the sky until July 21st, the date of its heliacal rising. That will be the date when Betelgeuse can be first observed in the predawn eastern sky. Of course, its appearance will be fleeting and one will have to look quickly to catch it . Betelgeuse, and the other Orion stars, will be easier to see by early to mid August. So, if Betelgeuse appears to go supernova now, it will be exceedingly difficult to see anything. Granted, Betelgeuse will become spectacularly bright for a few months and so it will be visible even when close to the Sun and might still be visible in the daytime sky. However, as it appears so close to the Sun, observing it will prove exceedingly difficult. Having Betelgeuse detonate itself into eternal oblivion now would prove to be a crashing disappointment. Imagine going to your local state fair one evening to watch the fireworks and while you're seated on the lawn enjoying your deep fried candy bar slathered in caramel, dappled with almonds, drizzled with powdered sugar and wrapped in your last will and testament you find out that the pyrotechnic show that fair officials promised would stagger Earth and offend Heaven had been rescheduled for the following week in southern Antarctica. You'd be a wee bit miffed. [image: 18B9238E-72C6-45D6-AF49FECF2D40E3CA_source.jpg] A telescopic view of Betelgeuse, the magnificent red supergiant star marking Orion's eastern shoulder. It has brightened considerably during the last two weeks, leading some to expect it to burn out as a Type II supernova. For what it's worth, we hope it remains with us for at least a few more months. Many astrophysicists are assuring us that our lamentations are unnecessary. Betelgeuse isn't about to die anytime soon. Credit: ESO/Digitized Sky Survey 2. Acknowledgment: Davide De Marti <https://www.eso.org/public/images/eso0927e/> If Betelgeuse perishes into incandescence now, the spectacle will be, shall we say, muted. Given our choice, we'd want to see Betelgeuse erupt around Christmas. Not only would this bedazzling sight induce more Zoroastrian priests to hasten across the desert again, it would afford all of us a golden opportunity to see the event all night long. And, believe you me, what a sight that would be to behold. A Type II supernova produces as much energy as an entire galaxy. An exploded Betelgeuse will not only be the brightest object in the night sky, but it would actually cast shadows on us all, at least for a few months. Eventually, the blaze would diminish into invisibility. Its ephemerality notwithstanding, it would put on an incredible once-in a-millennium show. So, if planitive shouts from a subterranean planetarium that's so obscure most people doubt its existence in the first place can make any difference, no, Betelgeuse, not now. Please wait a bit before you cast your vitality into the receiving void! Though we love you intensely, we all want a front row seat when you die. Of course, these desperate -not to mention pointless- calls might be wholly unnecessary. Many astrophysicists contend that Betelgeuse is not even close to its death knell. Like all stars, it generates energy through thermonuclear fusion reactions: fusing lighter elements into heavier ones and in the process transmutes some of the initial matter into energy. It is likely that this nine-million year old star is currently only in the helium-burning stage: the time when it is converting helium into carbon. Once it exhausts its core helium reserves, Betelgeuse will have to burn through its carbon and then the oxygen it formed out of the carbon and then the silicon that was created by the oxygen burning. Only when it reaches the point at which its core consists of pure iron heated to three billion degrees will the delicate balance between gravitational compression and the energy expansion be violently disrupted. The outer layers will collapse onto the core at half the speed of light. This collapse will precipitate the Type II supernova energetic enough to both create many of the elements heavier than iron and to disperse this material throughout its local galactic region. Betelgeuse could explode between 10,000 - 1,000,000 years for now, if it is indeed only working through the helium burning phase. That means, of course, that this gorgeous fire-opal star will continue to adorn our skies throughout the remainder of our lives and those of many generations to come. Well, whenever Betelgeuse blasts itself into smithereens, let's hope it is at least far enough from the Sun in our sky to give everyone a full and clear view of the spectacle. After all, Type II supernovae don't happen every day...well, at least not in our sky. *Before the deluge of complaints come gushing in, yes, we do understand that we never see the stars as they are now. Instead, we see images of stars as they appeared in the past. For instance, Betelgeuse is 620 light years away. So, if we see Betelgeuse explode now, we'll actually be watching an explosion that occurred 620 years ago. It is unfortunate that when humanity developed astronomy, it didn't spend a moment considering the damage it would inflict onto verb tenses. **The ability to harbor two wholly contradictory emotions simultaneously and comfortably is a skill that only a person who spends years in isolated observatories could possibly cultivate. 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