At 9:24:54 on December 12, 2023, Beijing time, the famous star Betelgeuse (Alpha Orion) almost disappeared from human sight.Of course, the second brightest star in Orion and the tenth brightest star in the sky did not really disappear, but encountered an "occultation"At that time, the asteroid 319 Leona passed in front of Betelgeuse, just between it and the Earth. Therefore, from some places on the Earth, Betelgeuse was blocked and its brightness suddenly decreased.
Previous predictions suggested that Betelgeuse would be obscured for about 7 seconds, or even disappear completely at one point, but it was actually much shorter and always had a certain brightness.
Some witnesses said they saw Betelgeuse dimming by about 50% for about 2 seconds, but there were also places where Betelgeuse's brightness remained basically unchanged.
This means that either Betelgeuse's apparent diameter is larger than expected, or the asteroid 319 Leona is smaller than expected.
Betelgeuse, also known as Alpha Orionis (Alpha Orionis), astronomical name Betelgeuse, is a red supergiant located in the constellation Orion. It has spectral type M1-2 and is about 640-724 light-years away from the Earth. Its diameter is about 887-955 times that of the sun.
If it were located at the center of the solar system, its surface would extend beyond the asteroid belt and possibly beyond the orbit of Jupiter, completely engulfing Mercury, Venus, Earth, and Mars.
Betelgeuse's apparent magnitude varies between 0.0 and 1.3. It is one of the largest stars that can be seen without binoculars, and it is also the first star outside the sun whose angular diameter has been measured.
Most of the time, Betelgeuse is only slightly dimmer than Eridanus, and slightly brighter than Centauri, and at infrared wavelengths it is brighter than any other star in the sky.
Although it is only 8 million to 8.5 million years old, a massive star that evolves rapidly is approaching the end of its life cycle.
At some point in the next million years, it will become a supernova.