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NGC 7538, near the more famous Bubble Nebula, is located in the constellation Cepheus.It is located about 9,100 light-years from Earth. It is home to the biggest yet discovered protostar which is about 300 times the size of the Solar System. [4]
Astronomers have long hypothesized that as a protostar grows to a size beyond 120 M ☉, something drastic must happen. [2] Although the limit can be stretched for very early Population III stars, and although the exact value is uncertain, if any stars still exist above 150–200 M ☉ they would challenge current theories of stellar evolution.
Below are lists of the largest stars currently known, ordered by radius and separated into categories by galaxy. The unit of measurement used is the radius of the Sun (approximately 695,700 km ; 432,300 mi ).
A protostar is a very young star that is still gathering mass from its parent molecular cloud. It is the earliest phase in the process of stellar evolution . [ 1 ] For a low-mass star (i.e. that of the Sun or lower), it lasts about 500,000 years. [ 2 ]
Some old writings envisaged the star as a very young protostar or a massive pre-main-sequence star with an age of only 1 Myr and typically a circumstellar disk. [15] It has probably evolved from a hot, dense O9 main sequence star of 5–20 R ☉ (solar radii). [28] [30] [64] The star has evolved rapidly because of its high mass. The time spent ...
Despite the uncertainty of the planet's properties, a 2017 study calculated HD 100546 b as a very highly reddened substellar object with a good-fit effective temperature of 2,630 K and a planetary mass and radius of 25 M Jup and 3.4 R Jup, making it still one of the largest exoplanets discovered by size. [25]
Brown dwarfs are substellar objects that have more mass than the biggest gas giant planets, but less than the least massive main-sequence stars.Their mass is approximately 13 to 80 times that of Jupiter (M J) [2] [3] —not big enough to sustain nuclear fusion of ordinary hydrogen (1 H) into helium in their cores, but massive enough to emit some light and heat from the fusion of deuterium (2 H).
A star is a massive luminous spheroid astronomical object made of plasma that is held together by its own gravity.Stars exhibit great diversity in their properties (such as mass, volume, velocity, stage in stellar evolution, and distance from Earth) and some of the outliers are so disproportionate in comparison with the general population that they are considered extreme.