Who knows the oldest star?

American astronomers have discovered what may be one of the oldest stars in the universe, and it is made up almost exclusively of material ejected from the universe. The star is about 13.5 billion years old, which means that there may be more low-mass, low-metal stars, some of which may be the first stars in the universe.

Kevin Schlaufman, the first author of the study and an associate professor at Johns Hopkins University in the United States, said that the newly discovered star has a very low metal content and a heavy element content equivalent to the mass of Mercury, indicating that it may be the first generation of stars after the big **. The Sun, by contrast, is a star thousands of generations from now.

Astronomers have discovered about 30 "supermetal-poor" stars with a similar mass to the Sun, but the newly discovered star is only 14 of the mass of the Sun, making it a companion star in a binary star system.

This ancient star is located on the same "thin disk" of the Milky Way as the Sun, suggesting that the Milky Way may be at least 3 billion years older than we previously thought.

The first stars produced in the post-universe were entirely composed of elements such as hydrogen, helium and a small amount of lithium, and elements heavier than helium were produced in the nuclei of these stars and dispersed with supernovae, and the metal content in the universe increased with the evolution of stars.

Astronomers have discovered one of the oldest stars in the universe, which has been around for 13.5 billion years. The star was named 2Mass J18082002-5104378 B, and has the lowest metal content of any known star. Because of its small mass, only about one-tenth of that of the Sun, it has not been discovered in the Milky Way for a long time.

he 1523-0901

According to Russia on May 11, the generally accepted age of the universe is 13.7 billion years old, and scientists have recently calculated that a star in the Milky Way called HE 1523-0901 is as old as 13.2 billion years old, almost "the same age" as the universe, and can be called the oldest star that came out at the beginning of the universe.

There is no way to calculate how many stars there are, and the question of the number of stars was only announced by Australian astronomers at the International Astronomical Union in 2003 that the entire visible universe is about 700 trillion billion stars. Not to mention the unseen universe that humans have not yet seen and touched.

There are about 700 trillion stars in the visible universe.

The specific number of stars in the universe is simply innumerable, galaxies like the Milky Way contain more than 200 billion stars, not to mention how many large and small galaxies there are in the universe, and how many stars are contained in them. In 2003, at the International Astronomical Union, astronomers said that there are about 700 trillion stars in the entire visible universe.

However, the most famous star for mankind should be the sun in the solar system. The planets in the solar system all revolve around the sun, and the sun moves around the center of the galaxy. About three-quarters of the mass of the sun is hydrogen, and the rest is helium and small parts of oxygen, carbon, iron and other elements, which are emitted by nuclear fusion.

If a celestial body has fuel supplied internally, is massive enough to ignite itself, generates fusion reactions inside, and thus shines and heats, and it has 9% of the volume of the Sun, then we can call it a star.

The largest star is Stevenson 2-18.

Stevenson 2-18, also known as Stephenson 2 DFK 1 or RSGC2-18, is a red supergiant located in the constellation Shield. Discovered by American astronomer Charles Bruce Stevenson in 1990. It is located near the open star cluster Stephenson 2, which is about 6,000 parsecs away from Earth (about 20,000 light-years, one parsec is about equal to light-years), and is considered one of a group of stars at a similar distance.

It is the largest star known to man and one of the brightest red supergiants, with a radius of about 2,158 times that of the Sun, which equates to a volume 10 billion times larger than the Sun. If you place it in the center of the solar system, its edge will engulf Saturn's orbit. If it replaces the Sun in our solar system, it will extend into Saturn's orbit.

Physical attributes of Stevenson 2-18

Stevenson 2-18 shows the features and characteristics of a red supergiant with a high rotten burner brightness, with a spectral type of M6, which is unusual for a supergiant, which places it in the upper right corner of the Herrault diagram.

The calculation of finding plug luminosity by fitting the spectral energy distribution yields that the star has a luminosity of nearly 440,000 times the solar luminosity and an effective temperature of 3200 K, indicating that the star has a very large radius, which would be much larger and brighter than the theoretically possible models of the largest and brightest red supergiant (about 1500 times the solar radius and 320,000 times the solar luminosity, respectively).

Another older calculation from 2010 still assumes that the members of the cluster are 5,500 parsecs away from Earth, but based on fluxes of 12 and 25 microns, gives a much lower, relatively modest brightness segment, or 90,000 times the luminosity of the sun. A newer calculation, based on the SED integral and assuming a distance of 5,800 parsecs, gives a value of 630,000 times the luminosity of the sun, although the authors suspect that the star is actually a member of a star cluster and is so far away.

Reference: Encyclopedia—Stevenson 2-18