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Stars that have magnitudes between 1.5 and 2.5 are called second-magnitude; there are some 20 stars brighter than 1.5, which are first-magnitude stars (see the list of brightest stars). For example, Sirius is magnitude −1.46, Arcturus is −0.04, Aldebaran is 0.85, Spica is 1.04, and Procyon is 0.34. Under the ancient magnitude system, all of ...
Many TNOs are often just assumed to have Pluto's density of 2.0 g/cm 3, but it is just as likely that they have a comet-like density of only 0.5 g/cm 3. [ 4 ] For example, if a TNO is incorrectly assumed to have a mass of 3.59 × 10 20 kg based on a radius of 350 km with a density of 2 g/cm 3 but is later discovered to have a radius of only 175 ...
She also used types such as B5A for stars halfway between types B and A, F2G for stars one fifth of the way from F to G, and so on. [60] [61] Finally, by 1912, Cannon had changed the types B, A, B5A, F2G, etc. to B0, A0, B5, F2, etc. [62] [63] This is essentially the modern form of the Harvard classification system. This system was developed ...
A class of extrasolar planets whose characteristics are similar to Jupiter, but that have high surface temperatures because they orbit very close—between approximately 0.015 and 0.5 AU (2.2 × 10 ^ 6 and 74.8 × 10 ^ 6 km)—to their parent stars, whereas Jupiter orbits its parent star (the Sun) at 5.2 AU (780 × 10 ^ 6 km), causing low ...
18 Tm – 123.5 AU – distance between the Sun to the farthest dwarf planet in the Solar System, the Farout 2018 VG18; 20.0 Tm – 135 AU – distance to Voyager 1 as of May 2016; 20.6 Tm – 138 AU – distance to Voyager 1 as of late February 2017; 21.1 Tm – 141 AU – distance to Voyager 1 as of November 2017
A difference of 5 magnitudes between the absolute magnitudes of two objects corresponds to a ratio of 100 in their luminosities, and a difference of n magnitudes in absolute magnitude corresponds to a luminosity ratio of 100 n/5. For example, a star of absolute magnitude M V = 3.0 would be 100 times as luminous as a star of absolute magnitude M ...
The planet may be similar in size and composition to Neptune, the smallest of our solar system's four gas planets. Neptune's diameter is about four times that of Earth.
An artist's concept of a planetary system. A planetary system is a set of gravitationally bound non-stellar bodies in or out of orbit around a star or star system.Generally speaking, systems with one or more planets constitute a planetary system, although such systems may also consist of bodies such as dwarf planets, asteroids, natural satellites, meteoroids, comets, planetesimals [1] [2] and ...