The Cuyahoga Astronomical Association (CAA) is pleased to announce that our 2021 OTAA convention at Letha House West will take place July 31. The Convention is intended for members of the CAA and members of other Northern Ohio astronomy clubs, not the general public. This year we plan to start the event at 2:00 p.m. We have a few hours scheduled for relaxation and socializing prior to our potluck dinner which is planned for 5:00. Following dinner, around 6:00, we plan to raffle off our door prizes. After the raffle there will be time to set up telescopes for evening observations, weather permitting. The club is looking forward to hosting the event after a one-year pause!
CAA will provide hot dogs, buns, and condiments; however, in order for this event to be a success we invite each attendee to participate in the potluck by bringing a dish of their choosing to share. Additionally, please bring your own beverages (no alcohol) as none will be provided.
Although high in the night’s sky, our waxing Gibbous Moon has been decidedly orange. Smoke, high in the atmosphere from North American wildfires, has tinted what should be a bright white Moon in the colors of moonset. Ruddy or not, we love that we can see mountain peaks and crater edges peeking up from the darkness just left of the sunlight terminator line.
The July 12, 2021 membership meeting of the Cuyahoga Astronomical Association (CAA) will take place via the Zoom online service beginning at 7:30 p.m. Join Alan Studt and Gale Franko as they relive their visit to the Very Large Array (VLA) in New Mexico. The site of these giant, moveable radio telescopes is where the movie Contact, was filmed.
Attendees may join the Zoom meeting beginning at 7:20 p.m. the nights of CAA scheduled meetings, and meetings begin at 7:30.
The evening will begin with introductions and a program by the featured speaker. The talk will be followed by the monthly membership business meeting, typically concluding at about 9 p.m. Guest attendees are welcome.
You can either “Phone in” or watch and participate via “Zoom Video”.
Phone In: Just dial: 1-312-626-6799 (Chicago number)
You will be required to enter our meeting number: 954 8268 6049
June 16, 2021 — When Betelgeuse, a bright orange star in the constellation of Orion, became visibly darker in late 2019 and early 2020, the astronomy community was puzzled. A team of astronomers have now published new images of the star’s surface, taken using the European Southern Observatory’s Very Large Telescope (ESO’s VLT), that clearly show how its brightness changed. The new research reveals that the star was partially concealed by a cloud of dust, a discovery that solves the mystery of the “Great Dimming” of Betelgeuse.
Betelgeuse’s dip in brightness — a change noticeable even to the naked eye — led Miguel Montargès and his team to point ESO’s VLT towards the star in late 2019. An image from December 2019, when compared to an earlier image taken in January of the same year, showed that the stellar surface was significantly darker, especially in the southern region. But the astronomers weren’t sure why.
The team continued observing the star during its Great Dimming, capturing two other never-before-seen images in January 2020 and March 2020. By April 2020, the star had returned to its normal brightness.
“For once, we were seeing the appearance of a star changing in real time on a scale of weeks,” says Montargès, from the Observatoire de Paris, France, and KU Leuven, Belgium. The images now published are the only ones we have that show Betelgeuse’s surface changing in brightness over time.
In their new study, published today in Nature, the team revealed that the mysterious dimming was caused by a dusty veil shading the star, which in turn was the result of a drop in temperature on Betelgeuse’s stellar surface.
Betelgeuse’s surface regularly changes as giant bubbles of gas move, shrink and swell within the star. The team concludes that some time before the Great Dimming, the star ejected a large gas bubble that moved away from it. When a patch of the surface cooled down shortly after, that temperature decrease was enough for the gas to condense into solid dust.
“We have directly witnessed the formation of so-called stardust,” says Montargès, whose study provides evidence that dust formation can occur very quickly and close to a star’s surface. “The dust expelled from cool evolved stars, such as the ejection we’ve just witnessed, could go on to become the building blocks of terrestrial planets and life,” adds Emily Cannon, from KU Leuven, who was also involved in the study.