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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 ]
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]
The planet has a mass less than 0.3 Jupiter masses (90 Earth masses) and a radius nearly equal to that of Jupiter, just 4% smaller, or the same as 10.7 Earth radii. [1] It is still enshrouded in an hydrogen envelope, and will shed its outer layers during its evolution, [2] becoming either a sub-Neptune, super-Earth or a sub-Saturn.
A star forms by accumulation of material that falls in to a protostar from a circumstellar disk or envelope. Material in the disk is cooler than the surface of the protostar, so it radiates at longer wavelengths of light producing excess infrared emission. As material in the disk is depleted, the infrared excess decreases.
A pre-main-sequence star (also known as a PMS star and PMS object) is a star in the stage when it has not yet reached the main sequence.Earlier in its life, the object is a protostar that grows by acquiring mass from its surrounding envelope of interstellar dust and gas.
HOPS 383 is a Class 0 protostar. It is the first Class 0 protostar discovered to have had an outburst, [1] and as of 2020, the youngest protostar known to have had an outburst. [1] The outburst, discovered by the Herschel Orion Protostar Survey (HOPS) team, was first reported in February 2015 in The Astrophysical Journal Letters. [2]
V883 Orionis is a protostar in the constellation of Orion. It is associated with IC 430 (Haro 13A), a peculiar Hα object surveyed by Guillermo Haro in 1952. [4] It is assumed to be a member of the Orion Nebula cluster at 414 ± 7 pc. [2] V883 Orionis, like most protostars, is surrounded by a circumstellar disc of dust.
This follows from the free-fall time ~ 1/√(gxdensity). The initial collapse of the core is quite fast; time ~ 1/√(6.7×10 −8 ×10 −18 g/cm 3) ~ 50,000–100,000 years or so. The lower density envelope takes longer to collapse accrete (collapse onto the protostar); time ~ millions of years or so. Roughly speaking, the Sun forms as shown ...