UY Scuti

UY Scuti is a very large star.

It is far away in space. You cannot see it with your eyes. It is much bigger than our Sun.

If it were in our space, it would be huge. It would reach past Mars. This star also changes its brightness. It grows dim and bright over time.

It is a very special star to study.

UY Scuti is a massive star in the Scutum constellation.

It is a red supergiant. This means it is a very large and bright star. It is also a variable star. This means its brightness changes over time.

It can be seen as dim or bright. You cannot see it with just your eyes. It is about 5,900 light-years away.

This star is one of the largest stars we know. Its size is hard to measure. Some say it is 750 million times the volume of our Sun. If we put it in our solar system, it would reach past Mars.

The star is also very cool. It loses mass by giving off gas and dust. Right now, the star is fusing helium. It also fuses hydrogen in a shell around its core. Later, it will make iron. This will cause the star to collapse. It will then end in a supernova. A supernova is a very big star explosion.

UY Scuti is a truly giant star located in the Scutum constellation.

It is known as a red supergiant or a hypergiant. This star is also a pulsating variable star. This means its brightness changes over time. It is too dim to see with just your eyes. It sits about 5,900 light-years away from Earth.

This star works by changing its size and light. It is a semiregular variable star. This means it pulses with a period of about 740 days. Inside the star, a special process is happening. It is currently fusing helium in its center. It also fuses hydrogen in a shell around that core. Eventually, the star will make iron in its core. This will cause the star to collapse and explode.

People first found this star in 1860. German astronomers at the Bonn Observatory cataloged it. They were working on the Bonner Durchmusterung Stellar Catalogue. They gave it the name BD-12°5055. This name shows its place in their star survey. Later, it was named UY Scuti. This name means it was the 38th variable star in Scutum.

Scientists use many numbers to describe this huge star. Some estimates say its volume is 750 million times the Sun. If placed in our solar system, it would reach past Mars. In 2012, the Very Large Telescope in Chile studied it. Scientists found it was much more luminous than the Sun. A 2023 measurement put its radius at 1,700 times the Sun. Its temperature is about 3,550K.

It is helpful to think about how big this star is. Imagine our Sun as a tiny marble. UY Scuti would be like a giant building next to it. It is also very dusty and loses mass every year. This creates a big cloud of gas and dust around it. It sits deep in the Milky Way disc. This makes it a metal-rich star. Even though it is huge, it is hard to see clearly. It sits in a place called the Zone of Avoidance.

UY Scuti is a massive red supergiant or hypergiant star.

It is located approximately 5,900 light-years away in the constellation Scutum. This star is also classified as a pulsating variable star. This means its brightness changes over time. Because of its distance and its location, it is too dim for naked-eye visibility. It has a maximum brightness of magnitude 8.29 and a minimum of magnitude 10.56.

The star is famous for its enormous size. Some estimates suggest its volume is 750 million times that of the Sun. If UY Scuti were placed at the center of our Solar System, its photosphere would extend past the orbit of Mars or even the asteroid belt.

Scientists use the Rosseland radius to measure such stars. This is the location where the optical depth is 2/3. In 2012, the Very Large Telescope in Chile helped determine its scale. Researchers found it was much more luminous than the Sun. They also found it was much larger than the Sun.

UY Scuti is a semiregular variable star. It has a pulsation period of approximately 740 days. This pulsation might be an overtone of its fundamental period. It could also be a fundamental mode if the star has a smaller radius. The star is also a maser source. This means it emits intense, concentrated radio waves from molecules like H2O, SiO, and OH. It is a dust-enshrouded star. It loses mass at a rate of 10^-4 solar masses per year. This loss creates a complex circumstellar environment of gas and dust.

Astronomers first cataloged the star in 1860. German astronomers at the Bonn Observatory were working on the Bonner Durchmusterung Stellar Catalogue. They gave it the designation BD-12°5055. This name indicates it was the 5,055th star in that specific section of the survey. During a second survey, they noticed the brightness had changed. This suggested it was a variable star. It was later named UY Scuti. This name marks it as the 38th variable star discovered in the constellation Scutum.

Measuring the exact size of UY Scuti is difficult. Different studies provide different numbers. In 2012, one analysis suggested a radius of 1,700 solar radii. This was based on an angular diameter of 51 milliarcseconds. However, Gaia Data Release 2 provided a different parallax. This suggested the star was much closer. A closer distance would mean a much lower luminosity and radius. In 2021, a new measurement used Gaia EDR3 data. It placed the distance at 9.3 kiloparsecs. A 2023 measurement estimated the radius at 1,700 solar radii. This study assumed an effective temperature of 3,550K.

The life of UY Scuti is driven by nuclear fusion. Currently, it is fusing helium in its core. It also fuses hydrogen in a shell around that core. Because it sits deep in the Milky Way disc, it is a metal-rich star. Eventually, the star will fuse heavier elements. When it begins to produce iron in its core, the balance will break. Gravity and radiation will no longer be in equilibrium. This will lead to a core collapse supernova.

Before the explosion, the star may change its appearance. It might evolve into a yellow hypergiant or a Wolf–Rayet star. It could also become a luminous blue variable. These stages involve strong stellar winds. These winds eject the outer layers of the star. This process eventually exposes the core. The star will then explode as a specific type of supernova. These include type IIb, IIn, or type Ib/Ic supernovae. This process represents the dramatic end of a massive star's life.