Stellar collisions are an amazingly rare occurrence. According to our best calculations, such events
occur once every 10,000 years in our galaxy (inside globular clusters).
Astronomers have only lately been able to see such mergers taking place, thanks to continual
developments in instrumentation and technology. No one has ever seen this phenomenon in action
before, but that could be about to change! Astronomers have discovered a binary star
system that is likely to collide and explode, resulting in a stunning explosion in the Earth's
sky in 2022. This binary star system is known as KIC 9832227
and is made up of two stars that orbit each other once every 11 hours or so.
According to a study conducted by Larry Molnar, an astronomy professor at Calvin College,
and his team, the binary star is expected to merge, resulting in a bright explosion
visible in the constellation Cygnus. This is a historic discovery because it will
allow scientists to observe a stellar merger and explosion for the first time in history.
Furthermore, they claim that observers on Earth will be able to see the explosion with
the naked eye. Molnar has been studying this binary star
system with the cooperation of Calvin College astronomy students since 2013.
Based on their measurements of the color and brightness of one of the two stars, the researchers
discovered that KIC 9832227 is part of a contact binary system, which means the two stars share
an atmosphere. Moreover, observations reveal that the star's
orbital period with its partner is rapidly decreasing, similar to how another contact
binary star, V1309 Scorpii, behaved before exploding in 2008. This strongly indicates
that the stars might actually merge. Molnar forecasts that in 2022, the stars will
collide and cause an explosion. Believing that KIC 9832227 would undergo a
similar destiny as V1309 Scorpii, they began running tests to check if it was behaving
in the same way. The first step was to conduct spectroscopic
observations to investigate if the presence of a companion star could explain their findings.
The next step was to calculate the pair's orbital period to check if it was getting
shorter with time, indicating that the stars were getting closer to each other.
In 2015, Prof. Molnar and his team predicted that the stars would collide eventually, culminating
in a type of supernova explosion known as a "red nova”. Initially, they said it would
happen between 2018 and 2020, but they later moved it to 2022.
Additionally, they believe that the resulting burst of light will be bright enough to be
seen from Earth. Because this star system is 1800 light-years away, which is six times
closer than that V1309 Scorpii, the “red nova” should be bright enough to be seen
with the naked eye. The star will be visible in the constellation
Cygnus, and it will appear as a new star in the iconic Northern Cross star pattern. This
is a once-in-a-lifetime opportunity, as no astronomer has ever been able to precisely
predict when and where a star collision would occur in the past.
Some news reports, feeling the need to exaggerate, claim it will be the brightest star in the
sky. It will most likely be the second magnitude, matching the Big Dipper's stars.
Even so, this will be fantastic, especially if you know enough backyard astronomy to recognize
Cygnus' shape and be thrilled by a new star that will extend Cygnus' right wing.
Molnar and his colleagues will closely watch KIC 9832227 over the course of the year in
multiple wavelengths. This will be done with the help of the NRAO's
Very Large Array (VLA), NASA's Infrared Telescope Facility at Mauna Kea, and the ESA's XMM-Newton
satellite. These observatories will study the radio,
infrared, and X-ray emissions of the star, respectively.
If everything goes according to plan, the astronomers will have captured a binary star
in the act of exploding for the first time. The bottom line is that the merging-star idea
should be taken seriously right now, and astronomers should spend the next year or less intensely
studying it so that if it does blow up, they will know what caused it.