As of right now Tabby's star rightfully holds the title of the galaxy's strangest star,
but there are two others that defy explanation and even years after their discovery they
remain mysteries.
One of them should not exist at all.
And the other is missing something really important.
Located in the constellation Leo, there exists a star known as SDSS J102915 + 172927, that
one taxes even my abilities to rattle off numbers.
This star defies explanation.
The star is composed almost entirely out of hydrogen and helium.
Stars typically have some heavier elements in small quantities, a few percent for our
own sun and less for older stars, but this star has almost none.
This is thought to be vital in star formation however.
The heavier elements come together through gravity to form a core that then attracts
hydrogen and helium until the star has enough material to begin fusion reactions when enough
heat and pressure are built up.
However, hydrogen and helium alone are not thought to be heavy enough to condense into
a star by themselves.
They are simply too light.
Enter this weird star.
One thing about this star is that it's extremely old, coming in at about 13 billion years of
age, far older than our sun and is one of the oldest stars ever found.
It's also a little smaller than the sun.
But what's strange is that it has the lowest observed amount of heavier elements in a star's
composition so far seen, about 20,000 times smaller than the amount in our sun.
So much so that it should have never have been able to condense in the first place if
the standard model of star formation is correct.
Apparently it isn't.
Another head-scratcher regarding this star is its very low levels of lithium.
A star this old that approaches the time of the big bang should be composed of the same
things that the universe at the time was thought to be composed of.
The lighter elements.
Everything else came later and that explains why the star has so little heavier material.
But it turns out that the star has 50 times less lithium than what was thought to be produced
after the Big Bang making this star a dual mystery.
Could our theories on how stars form be wrong?
Why is this star so freakish?
Those questions remain unanswered, though they probably eventually will be answered
as more stars like this are found and studied.
And that brings us to our second story which may never be solved at all because it remains
really unique and probably will remain so.
There is a young star named TYC 8241 2652 that presented a mystery to astronomers that
may never be solved because what they wanted to study regarding the star up and disappeared.
When they first started observing this star in 1983 it was surrounded by enormous amounts
of dust and gas glowing brightly in the infrared.
It predictably stayed that way for a quarter of a century.
This accumulation of dust and gas is not unusual.
The star is young and in a stage where protoplanets are still crashing into each other in its
solar system and forming into planets.
That gas and dust absorbs energy from the star and then reradiates it into space in
the infrared.
It warms everything up in effect.
Nothing out of the ordinary there.
But then all the material suddenly just disappeared.
In 2010 NASA's WISE spacecraft discovered that the material was apparently gone, which
was confirmed a few years later with a ground telescope.
The dust and gas is simply gone in the same way as if the asteroid belt around the sun
just suddenly up and disappeared.
Things like that don't just happen in regards to astronomical objects.
But in this case, they did.
And what's even weirder is that it did it really fast.
The universe does not usually work on short time scales, especially not over human time
scales of just a few years.
Typically natural processes as planetary discs condensing into planets occurs over timescales
of millions of years.
It can't happen much faster than that in most cases.
But here it did it in just a few years?
Not likely.
So something else must have happened.
There are a number of theories about how it might have happened ranging from an impact
causing the disc to fall into the star or something causing the dust to crush into smaller
undetectable particles, but no theory seems particularly satisfying and to this day no
one really knows where all that material went.
Was the material harvested by someone or something for some purpose?
Very probably not, but we'll never know for sure.
Thanks for listening.
I am futurist and science fiction author John Michael Godier, and be sure to check out my
books at your favorite online book retailer and subscribe to my channel for in-depth regular
explorations into the interesting, weird and unknown aspects of this amazing universe in
which we live.