- 4260 - BETELGEUSE - passed by asteroid? - Asteroid “319 Leona” will pass directly in front of Betelgeuse, the red giant in the constellation of Orion whose name amusingly translates to “armpit of the giant”. An asteroid will occult Betelgeuse on December 12, 2023. We still use mathematics with roots centuries old to calculate the position of objects in our Solar System.
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4260 - BETELGEUSE
- passed by asteroid?
-
- To be able to
calculate that a rock approximately 60 km across is going to pass directly in
front of a star that is just over 650 light years away is really quite
staggering.
-
- Betelgeuse is the
second brightest star in the constellation Orion and is a familiar favorite
with its piercing red color. It hit the news back in 2020 when it unexpectedly
dimmed in the sky due to the star itself ejecting a cloud of dust.
-
- It will fade for a
few seconds due to the passage of Leona right in front of it. An event like
this is quite rare where the light from a bright star is blocked (or occulted)
by an asteroid happening every few decades at most.
-
- The size and shape
of the asteroid itself is still subject to debate. Typically we tend to assume
asteroids are spherical unless we know otherwise but a previous occultation of
Leona in September 2023 determined that it was more of ellipsoidal in shape
measuring 80km by 55km.
-
- At its distance
from Earth that means it will cover an area of sky 46 x 41 milli-arcseconds
which is a little more than the approximate 40 milli-arcseconds for
Betelgeuse. This suggests Betelgeuse
will be completely blocked from view and therefore blink out for a few seconds.
-
- Betelgeuse’s
somewhat diffuse outer atmosphere may mean its apparent size is more like 50
milli-arcseconds so it just fades instead.
Until the event happens we will not know exactly how it will appear in
the sky or exactly when.
-
- Betelgeuse,
usually the 10th-brightest star in the night sky, will briefly blink off
Monday, December 11. The event, which
will last only 12 seconds, will be a valuable opportunity for astronomers to
create a map of the giant star's surface, which has been linked to its recent
odd behavior.
-
- In addition to
being a short event, the occultation will be visible only from a narrow path
stretching from Asia to southern Europe, Florida and eastern Mexico. The
International Occultation Timing Association has a special page dedicated to
the event that includes a downloadable Google Earth file showing the complete
path. Viewers within the path will be able to see the occultation without
binoculars or a telescope, though both will help enhance the view of the rare
event.
-
-
- To find Betelegeuse
from the Northern Hemisphere in December, look due east about two hours after
sunset, and you'll see the three stars of Orion's Belt — Alnitak, Alnilam and
Mintaka — rising into the sky. To their left, Betelgeuse will be level with
Mintaka.
-
- These kind of
occultations are very useful to constrain the shape of the asteroid involved.
The occultation may allow scientists to map the surface of Betelgeuse. We will be hopefully able to learn more about
its large convective cells, which is driving its variable brightness.
-
-
December 8, 2023
BETELGEUSE -
passed by asteroid? 4260
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