Suzie Dills| Special to The Canton Repository
Sky Shorts: Will Comet Tsuchinshan-ATLAS C/2023 A3 put on a celestial show
Comet Tsuchinshan-ATLAS (C/2023 A3), a cosmic dinosaur, formed 4.6 billion years ago along with the sun and planets. It has resided in the outer solar system in the Oort cloud, which surrounds the entire solar system. The Oort Cloud contains billions of comets, and it marks the edge of the solar system, two light years away.
Comets, sometimes called dirty snowballs made up of dust, rock and ice, are classified according to their orbital period. Short-period comets orbit the Sun in 200 years or less and mostly come from the region just beyond Neptune. Long-period comets come from the Oort cloud. Comet C/2023 A3 has a nearly hyperbolic orbit. It will either have a very long period orbit of 80,000-plus years or once it passes the Sun it may get ejected from our solar system. Astronomers know that Comet C/2023 A3 is coming from the Oort cloud due to the steep angle of its orbit. Comet Tsuchinshan-ATLAS has been nudged into a nosedive, possibly from galactic tides, sending it through the inner solar system passing just outside the orbit of Mercury.
Comet Tsuchinshan-ATLAS was discovered at Purple Mountain Observatory in China on Jan. 9, 2023, but no follow-up observations were reported due to difficulty relocating after the initial sighting. It was officially recorded as “lost.” Fortunately, the Asteroid Terrestrial Impact Alert System relocated it on Feb. 22, 2023.
Comet C/2023 A3, has never passed by the Sun, so we have no idea how it will respond. As many comets have done before, it could disintegrate at its close approach to our star, living a short life of two years since discovery. It will make its closest approach, to the Sun, on Sept. 27, then to Earth on Oct. 12. It will start in the predawn sky 14 degrees south of the waning crescent Moon on Sept. 30. It will move rapidly eastward and emerge into the evening sky. Comet C/2023 may surge to brightness around Oct. 9, when it passes nearly between Earth and the Sun. Looking west starting on Oct. 14, it will climb higher through the constellation Ophiuchus each evening.
If it survives the trip through the inner solar system, it will either return in 80,000 years or be flung into interstellar space. I’m crossing my fingers that we get a chance to see it!
Night sky for September
On the night of Sept. 17-18, we will enjoy a very partial lunar eclipse. A very small portion of Earth’s umbra shadow eclipses the Moon. Partial eclipse begins at 10:12 p.m., maximum at 10:44 p.m. and partial ends at 11:15 p.m.
The first day of autumn or the autumnal equinox is Sept. 22 at 8:44 a.m.
Planets and the Moon:
The full harvest moon occurs Sept. 17.
Right after sunset, find a good western view to spot brilliant Venus at magnitude -3.9. Venus sets up to one hour after sunset. On Sept. 4, the waxing crescent Moon is less than five degrees west of Venus. Then on Sept. 5, the two object switch positions and the Moon is seven degrees southeast of Venus. Venus will remain low in the west after sunset for September.
Saturn reaches opposition on Sept. 8, so it will be visible from sunset to sunrise. Golden colored Saturn reaches its peak magnitude for the year, briefly, shining at magnitude 0.5, in the constellation Aquarius. Saturn pairs with the full moon on Sept. 17.
Neptune starts the month 12 degrees east of Saturn, at magnitude 7.7. On Sept. 18, the full moon passes within two degrees of Neptune. Binoculars or a telescope are needed.
Uranus becomes stationary and can be found five degrees southwest of the Pleiades. It rises shortly before 11 p.m. Sept. 1 and two hours earlier by month’s end. The waning gibbous Moon passes five degrees north of Uranus on Aug. 22. Binoculars or a telescope offer the best views.
Jupiter rises around midnight in early September. Jupiter is brilliant shining bright at magnitude -2.3. Jupiter can be found 10 degrees northeast of the bright red, orange star Aldebaran in the constellation Taurus. The last quarter moon passes north of Jupiter on Sept. 23-24.
Mars opens the month between the horns of Taurus, shining at magnitude 0.7. It crosses into Gemini and can be found 16 degrees north of the bright red, orange star Betelgeuse. It rises before 1 a.m. at the beginning of September and 40 minutes earlier by the month’s end.
Mercury and the slender crescent moon make a lovely pairing in the predawn sky, on Sept. 1. Mercury, shining at magnitude 0.5, is four degrees to the south of the Moon. Mercury reaches its greatest western elongation on Sept. 4, at magnitude -0.2.
Night Sky Spotlight:
A sure sign of autumn is the return of the beautiful, winged horse, Pegasus, to our evening sky. When you head out on a clear evening, look east for four stars the form a large square in the sky. This asterism, or pattern, is referred to as the Great Square of Pegasus, or the body of the winged horse. You can also think of it as a baseball diamond. This pattern is twenty degrees wide from top to bottom. That would be two fists wide.
Pegasus is the seventh largest of the 88 official constellations. The star closest to the horizon is Algenib; the star opposite Algenib is Scheat; the star to the south is Markab; and the final star is Alpheratz. Extending from Markab are two stars, Homan and Biham, that lead the way to the head star Enif. Pegasus’ forelegs extend from Scheat.
Pegasus is home to many galaxies, such as the famous Stephan’s Quintet, which is a tight gathering of five galaxies. Another deep sky object of note is a globular star cluster, Messier 15 which is four degrees straight out from Enif, while using binoculars. In 1995, the first exoplanet orbiting a sun-like star was discovered in the constellation Pegasus. The planet was named 51 Pegasi b after the star it orbits.
If you like star stories, Pegasus is a part of one of the most elaborate Greek mythology stories from 3,000 years ago. The hero Perseus rode on the back of Pegasus when he rescued the princess Andromeda from the sea monster Cetus.
For further night sky details, maps and audio, visit my website www.starrytrails.com.
Visit the Hoover Price Planetarium
There will be planetarium shows every Saturday & Sunday starting Sept. 7. Visit www.mckinleymuseum.org, for show dates and times! Planetarium shows are free with museum admission. The planetarium is located inside the McKinley Presidential Library & Museum, 800 McKinley Monument Drive, N.W., in Canton, Ohio. For more information, please call the Museum at 330-455-7043.
