Star

The nearest star to Earth is the Sun.

The Sun is the star at the center of the Solar System.

Historically, the most prominent stars were grouped into constellations and asterisms, the brightest of which gained proper names.

A constellation is a group of stars that forms an imaginary outline or pattern on the celestial sphere, typically representing an animal, mythological person or creature, a god, or an inanimate object.

A star is an astronomical object consisting of a luminous spheroid of plasma held together by its own gravity.

Gravity, or gravitation, is a natural phenomenon by which all things with mass or energy—including planets, stars, galaxies, and even light —are brought toward (or gravitate toward) one another.

A star is an astronomical object consisting of a luminous spheroid of plasma held together by its own gravity.

Examples of astronomical objects include planetary systems, star clusters, nebulae, and galaxies, while asteroids, moons, planets, and stars are astronomical bodies.

Historically, the most prominent stars were grouped into constellations and asterisms, the brightest of which gained proper names.

In observational astronomy, an asterism is a popularly known pattern or group of stars that can be seen in the night sky.

The observable Universe contains an estimated 1e24 stars, but most are invisible to the naked eye from Earth, including all stars outside our galaxy, the Milky Way.

A galaxy is a gravitationally bound system of stars, stellar remnants, interstellar gas, dust, and dark matter.

Astronomers have assembled star catalogues that identify the known stars and provide standardized stellar designations.

A star catalogue (Commonwealth English) or star catalog (American English), is an astronomical catalogue that lists stars.

A star is an astronomical object consisting of a luminous spheroid of plasma held together by its own gravity.

The interior of the Sun is an example of fully ionized plasma, along with the solar corona and stars.

For at least a portion of its life, a star shines due to thermonuclear fusion of hydrogen into helium in its core, releasing energy that traverses the star's interior and then radiates into outer space.

Hydrogen is the most abundant chemical substance in the Universe, constituting roughly 75% of all baryonic mass. Non-remnant stars are mainly composed of hydrogen in the plasma state.

The observable Universe contains an estimated 1e24 stars, but most are invisible to the naked eye from Earth, including all stars outside our galaxy, the Milky Way.

It is estimated to contain 100–400 billion stars and more than 100 billion planets.

Many other stars are visible to the naked eye from Earth during the night, appearing as a multitude of fixed luminous points in the sky due to their immense distance from Earth.

Generally, the fixed stars are taken to include all stars other than the Sun.

The total mass of a star is the main factor that determines its evolution and eventual fate.

Stellar evolution is the process by which a star changes over the course of time.

For at least a portion of its life, a star shines due to thermonuclear fusion of hydrogen into helium in its core, releasing energy that traverses the star's interior and then radiates into outer space.

There are two forms of thermonuclear fusion: uncontrolled, in which the resulting energy is released in an uncontrolled manner, as it is in thermonuclear weapons ("hydrogen bombs") and in most stars; and controlled, where the fusion reactions take place in an environment allowing some or all of the energy released to be harnessed for constructive purposes.

For at least a portion of its life, a star shines due to thermonuclear fusion of hydrogen into helium in its core, releasing energy that traverses the star's interior and then radiates into outer space.

Large amounts of new helium are being created by nuclear fusion of hydrogen in stars.

Astronomers can determine the mass, age, metallicity (chemical composition), and many other properties of a star by observing its motion through space, its luminosity, and spectrum respectively.

Stellar mass is a phrase that is used by astronomers to describe the mass of a star.

For at least a portion of its life, a star shines due to thermonuclear fusion of hydrogen into helium in its core, releasing energy that traverses the star's interior and then radiates into outer space.

Local concentrations of matter have condensed into stars and galaxies.

Astronomers can determine the mass, age, metallicity (chemical composition), and many other properties of a star by observing its motion through space, its luminosity, and spectrum respectively.

Astronomical spectroscopy is the study of astronomy using the techniques of spectroscopy to measure the spectrum of electromagnetic radiation, including visible light and radio, which radiates from stars and other celestial objects.

A star's life begins with the gravitational collapse of a gaseous nebula of material composed primarily of hydrogen, along with helium and trace amounts of heavier elements.

Star formation is the process by which dense regions within molecular clouds in interstellar space, sometimes referred to as "stellar nurseries" or "star-forming regions", collapse and form stars.

Stars can form part of a much larger gravitationally bound structure, such as a star cluster or a galaxy.

Star clusters are very large groups of stars.

Astronomers can determine the mass, age, metallicity (chemical composition), and many other properties of a star by observing its motion through space, its luminosity, and spectrum respectively.

In astronomy, luminosity is the total amount of electromagnetic energy emitted per unit of time by a star, galaxy, or other astronomical object.

Astronomers can determine the mass, age, metallicity (chemical composition), and many other properties of a star by observing its motion through space, its luminosity, and spectrum respectively.

They observe astronomical objects such as stars, planets, moons, comets, and galaxies – in either observational (by analyzing the data) or theoretical astronomy.

Astronomers can determine the mass, age, metallicity (chemical composition), and many other properties of a star by observing its motion through space, its luminosity, and spectrum respectively.

For example, stars and nebulae with relatively high abundances of carbon, nitrogen, oxygen, and neon are called "metal-rich" in astrophysical terms, even though those elements are non-metals in chemistry.

They have been part of religious practices and used for celestial navigation and orientation.

Celestial navigation uses "sights", or angular measurements taken between a celestial body (e.g. the Sun, the Moon, a planet, or a star) and the visible horizon.

The oldest accurately dated star chart was the result of ancient Egyptian astronomy in 1534 BC.

They are used to identify and locate constellations and astronomical objects such as stars, nebulae, and galaxies.

In 185 AD, they were the first to observe and write about a supernova, now known as the SN 185.

This transient astronomical event occurs during the last evolutionary stages of a massive star or when a white dwarf is triggered into runaway nuclear fusion.