Star

Stars represent substantial cosmic entities, emitting both heat and radiation. Their composition includes a core of helium and hydrogen gas undergoing combustion in a plasma state. The extreme temperatures facilitate nuclear fusion, resulting in temperatures reaching approximately 5,500 degrees on the inner surface, referred to as the "photosphere." Enveloping the photosphere is the "chromosphere," a cooler gaseous stratum that imparts a distinctive color to the star. At the periphery of a star's surface lies the corona, characterized by rarefied gas.

During the age of the High Republic Era, stars were categorized based on their chemical composition, with examples like R-class stars exhibiting elevated levels of nitrogen. Exposure to sunlight could darken a human's skin; Sergeant [Tonra](/article/tonra], usually fair-skinned, experienced significant reddening after two weeks in the sun. Protecting infants from the sun was essential; Sola Naberrie ensured her newborn, Ryoo, had sun protection before outdoor activities. Plants also derive nourishment from solar radiation.

Within the galaxy, there exist seven categories of stars that are considered main sequence:

• " O " stars exhibit a blue hue and have a relatively short existence, spanning less than a million years. For instance: Garnib. [3]

• " B " stars present a blue-white appearance and endure for approximately ten million years. For instance: Kessa. [3]

• " A " stars are characterized by their white color and can persist for durations ranging from four hundred million to two billion years. For instance: Colu. [3]

• " F " stars display a yellow-white coloration and have a lifespan of around four billion years. For instance: Ropagi. [3]

• " G " stars are yellow in color and possess a lifespan of about ten billion years. For instance: Corell. [3]

• " K " stars exhibit an orange tint and can exist for up to sixty billion years. For instance: Yavin. [3]

• " M " stars are red, emitting minimal light and heat, and boast lifespans exceeding one hundred trillion years. They are also known as red dwarfs. For instance: Barab. [3]

The sequence starts with the largest O-class stars and gradually decreases in size to the smallest M-class stars.

The non-main sequence stars include:

Pre-main sequence (smaller than M-class stars):

• Brown dwarf. Example: Doornik-1142. [3]
• Protostar. Example: Black Bantha Nebula. [3]

Post main-sequence (bigger than O-class stars):

• Red giant. Example: Sokor. [3]
• Blue giant. Example: Ku'Baku. [3]
• Red supergiant. Example: Primus Goluud. [3]

Compact stars:

• White dwarf. Example: Ardos. [3]
• Black dwarf. Example: A star in The Ring. [3]
• Neutron star. Example: Oolex pulsar. [3]
• Black hole. Example: Endor Gate. [3]

Additional unusual star classifications existed that did not neatly align with this established categorization, such as Asar, which was regarded as a blue dwarf, and yellow dwarfs.

Stars originate within stellar nurseries, regions of space, through the convergence of energy in the forms of pressure and heat. This process shapes the surrounding environment and is visible from vast distances, spanning millions of kilometers. The implosion of a nebula or the initiation of a planet's core by external forces can also give rise to star formation. Chirrut Îmwe once stated that the "strongest stars" contain [kyber](/article/kyber_crystal] at their core. During their formative stages, which can take millions of years, stars are classified as either protostars or brown dwarfs, with the latter being too small to sustain hydrogen fusion and eventually fading away.

Upon reaching their mature size, stars frequently release clouds of gas and dust, which then coalesce into planets and other celestial bodies. In such instances, these stars are referred to as suns. A sun, along with all the objects gravitationally bound to it, constitutes a planetary system. Some planetary systems may feature multiple suns, as exemplified by the planets Tatooine and Mon Cala. Life depends on the presence of stars.

Typically, a planet orbiting a star receives both light and warmth from it, although exceptions do exist. Umbara is known as the "Shadow World" due to its sun's rays being perpetually obscured, resulting in constant darkness. Distant stars appear as mere specks of light in the night sky. These points are conventionally grouped into constellations. Without a star, most worlds would become desolate and frozen. The size and distance of a sun significantly influence the characteristics of its orbiting planets.

On the planet Coruscant, stars are difficult to discern due to the pervasive [city](/article/city] lights of the sprawling [ecumenopolis](/article/ecumenopolis]. However, according to young Obi-Wan Kenobi, they can be observed with the right knowledge. Stars can serve as navigational aids: Young Kenobi utilized them to find his way back to the [Jedi Temple](/article/imperial_palace] after assisting fellow Jedi Initiate Gehren Rand, who had run away.

Following their time on the main sequence, the fusion reactions within a star gradually cease, causing them to expand into blue or red giants. Just before the complete cessation of fusion, stars transform into red supergiants, which subsequently collapse in a cataclysmic explosion known as a [supernova](/article/supernova]. These exploding stars then evolve into either highly radioactive neutron stars or, in the case of exceptionally large stars, a singularity within a black hole. Smaller to medium-sized stars become white dwarfs, which eventually fade into [black dwarfs](/article/black_dwarf] after billions of years.

Resistance member Karé Kun once described stars as "giant balls of exploding gas." Prime Minister Dreand Yens once commented that the twinkling of stars in the sky was due to their constant burning to sustain themselves, which he took as evidence that nature's beauty stems from its functionality.