Betelgeuse supernova: coming soon?

A paper published this month claims that the red supergiant star Betelgeuse could go supernova in the next few decades! Since Betelgeuse is 600 light years away, it actually might've already gone supernova (we just can't see it yet as the light takes 600 years to reach us).

Astronomers have been observing Betelgeuse for a very long time. It has pretty weird brightness patterns, dimming and brightening frequently. These changes in brightness are thought to be due to pulsations in the star, caused by a tug of war between the inward force of gravity and the outward force of the star's gas pressure. By observing the frequency of these pulsations, Saio et al determined that the pulsations can only be explained by a fusion of carbon into heavier elements (namely neon and magnesium) rather than hydrogen to helium.

Fusion takes place in a star's core. As a star is on the main sequence, it survives by fusing hydrogen atoms into helium. Eventually, the star will run out of hydrogen, being left with a helium core; when this happens, there is no longer a process which opposes the force of gravity – the star will begin to contract due to its own gravity. However, this causes the core to become hotter and denser, allowing for helium fusion to take place (which turns into carbon) etc... I hope you see where I'm going with this? Betelgeuse is now at the stage where carbon is being fused in its core and it will continue to fuse heavier elements till it reaches iron. The process begins to break down at iron because fusing iron gives you less energy out than you put in. Now, there is nothing which can save the star from going supernova.

The fusing stages of heavier elements do not last very long – typically 100s of years for a star like Betelgeuse. Saio et al found that Betelgeuse is almost out of carbon (much less than 20% remaining), meaning that its collapse is getting ever closer. This is super exciting as the last supernova we've seen in our galaxy (the Milky Way) was in 1604: SN1604. The prospect of seeing a supernova with our own eyes along with being able to study it and its remnant (a neutron star) is precisely why this paper has gained so much attention.

JWST images Enceladus plumes

A water vapour plume from Saturn’s moon Enceladus spanning more than 6,000 miles has been detected by researchers using NASA’s James Webb Space Telescope. Not only is this the first time such a water emission has been seen over such an expansive distance, but JWST is also giving scientists a direct look, for the first time, at how this emission feeds the water supply for the entire system of Saturn and its beautiful rings.

Enceladus is an ocean world about 4% the size of Earth (just 313 miles across) – it's currently one of the most exciting targets in our Solar System in the search for life beyond Earth. Between the moon's icy outer crust and rocky core lies a huge reservoir of salty water! In the coming years, JWST will serve as the primary observation tool for Enceladus; discoveries will help inform future Solar System satellite missions that will look to explore the subsurface ocean’s depth, how thick the ice crust is, and more.

Supermoon

Our Moon becomes a 'supermoon' in the month of July. A supermoon is a full moon or a new moon that nearly coincides with perigree – the closest that the Moon comes to the Earth on its elliptical orbit. The Moon will look slightly bigger from our point of view (14% bigger and 30% brighter than a 'micromoon', when the Moon is the furthest away from the Earth (at the apogee)). Sadly, the human eye can't really make out this change in size, so the Moon won't look too different when you look up at it this coming month :*( Still cool to know though, I think?

published: 27/06/23 by kaan evcimen