2023-07-29 04:00:00
Posted at 12:00 a.m.
“The Brightest I’ve Seen”
André Cajolais has been an amateur astronomer for 30 years. Since the end of May, like dozens of other enthusiasts in Quebec, he has been captivated by a new supernova, SN2023ixf. “I observed it in Chambly despite the smoke from the forest fires,” says Mr. Cajolais, who often does scientific communication as a member of the Société d’astronomie de la Montérégie. “It’s probably the brightest I’ve seen. »
PHOTO CHARLES WILLIAM PELLETIER, THE PRESS
Georges (on the left) and François Simard discuss in the observatory of the Club d’astronomie du Bois-de-Belle-Rivière, in Mirabel.
Same observation at the Club d’astronomie du Bois-de-Belle-Rivière, in Mirabel. On June 19, half a dozen amateur astronomers took advantage of a rare clear sky to observe SN2023ixf. “The sky conditions were excellent and no flies! “, says Georges Simard, administrator of the club. He took the opportunity to send a snapshot of the supernova to a citizen science site. “Thanks to these dozens of observations from around the world, we see the luminosity of the supernova slowly decreasing. An article on SN2023ixf published in July in the Research Notes of the American Astronomical Society (RNSAA) included contributions from three club members.
PHOTO ANDRE CAJOLAIS AND PAUL PARADIS
The supernova SN2023ixf (at the end of the green arrow), in the Moulinet galaxy
A gigantic explosion
A supernova marks the end of the life of a star, with in particular an explosion emitting a lot of light. They probably occur frequently in the Universe, but one can count on the fingers of both hands the supernovae observed before the 20th century. The very concept of supernova dates from the middle of the 19th century.
PHOTO CHARLES WILLIAM PELLETIER, THE PRESS
The observatory of the Bois-de-Belle-Rivière Astronomy Club, in Mirabel
SN2023ixf is located 21 million light-years from our planet, in the galaxy Messier 101, also called the Moulinet galaxy, in the constellation Ursa Major.
The explosion is so gigantic that it surpasses in luminosity the very heart of the galaxy.
André Cajolais, member of the Astronomical Society of Montérégie
SN2023ixf was first observed on May 19 by a Japanese amateur astronomer.
Supernovae very close to Earth, located less than 100 or 150 light-years away, have been linked to species extinctions that occur every few million years. There are no such nearby stars that seem likely to become supernovae in the next few centuries or millennia, the closest being Betelgeuse, between 500 and 600 light years away.
In the movie Star Trek of 2009, the destruction of a Romulan civilization by a supernova played a central role.
A little throwback to the 2nd century…
The apparent light from supernovae is usually too faint to see with an amateur telescope, according to Marc Jobin, astronomer at the Planetarium. “They usually have magnitudes greater than 13, while SN2023ixf has a magnitude of 11,” says Jobin. Paradoxically, the higher the magnitude value, the less a star is visible.
PHOTO CHARLES WILLIAM PELLETIER, THE PRESS
Georges Simard and his Unistellar eVscope telescope
To be visible to the naked eye, the magnitude must be less than 6, under ideal conditions. For example, the stars of the Big Dipper that draw a pan in the sky have a magnitude of 2 to 3.
In 1987, in the Large Magellanic Cloud, located 170,000 light years from Earth, a supernova reached a magnitude of 2.9.
“The magnitude scale is logarithmic, so one unit of difference means a large change in visibility,” says Jobin. A magnitude 2 star is 2512 times more visible than a magnitude 3 star, and 100 times more visible than a magnitude 7 star.
PHOTO FROM NASA WEBSITE
The Moulinet galaxy sketched by the space telescope Hubble
This scale was created by Ptolemy, a 2nd century Greek geographer and astronomer. “At the time, it had six degrees of magnitude,” says Mr. Jobin. It wasn’t very mathematical, he classified the stars into several sizes. »
L’Almageste by Ptolemy listed 1022 stars visible to the naked eye. The invention of the telescope in the 17th century made it possible to add higher degrees of magnitude, and therefore to classify less visible stars or supernovae. The logarithmic scale was formalized in the middle of the 19th century by the British astronomer Norman Pogson, which led to the addition of negative magnitudes for the most visible stars.
Comment observer SN2023ixf
The Pinwheel Galaxy is located between the Big Dipper and the Little Dipper, near the handle of the pan (the Big Dipper). SN2023ixf is located near one of the outer arms of the galaxy (it is not always in the same place because the galaxy rotates). It should be visible all summer, according to Mr. Jobin, the space.com site even advancing that it would be visible in the fall. “The best thing for a neophyte is to call the amateur astronomy society in his region for help,” says Mr. Simard. You can also find star finder sites or applications [star finder]. »
Learn more
20 Number of supernovae that have appeared within 1000 light-years of Earth over the past 11 million years
Sources : Université Washburn, NASA
2 to 3 Number of supernovae that appear in a century in the Milky Way
Sources : Université Washburn, NASA
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