Bow shocks in astrophysics magnetized, such as Jupiter or Saturn. Earth's bow shock is about thick and located about from the planet. Bow shocks form at comets as a result of the interaction between the solar wind and the cometary ionosphere. Far away from the Sun, a comet is an icy boulder without an atmosphere. As it approaches the Sun, the heat of the sunlight causes gas to be released from the cometary nucleus, creating an atmosphere called a coma. The coma is partially ionized by the sunlight, and when the solar wind passes through this ion coma, the bow shock appears. The first
Planet mass until the object collapses into a sphere. Mass is also the prime attribute by which planets are distinguished from stars. The upper mass limit for planethood is roughly 13 times Jupiter's mass for objects with solar-type isotopic abundance, beyond which it achieves conditions suitable for nuclear fusion. Other than the Sun, no objects of such mass exist in the Solar System; but there are exoplanets of this size. The 13-Jupiter-mass limit is not universally agreed upon and the Extrasolar Planets Encyclopaedia includes objects up to 20 Jupiter masses, and the Exoplanet Data Explorer up to 24 Jupiter masses. The