G type main sequence star11/11/2023 Watch this amazing video of the Sun taken by NASA’s Solar Dynamics Observatory. In its core, the Sun fuses 620 million metric tons of hydrogen each second. The Sun’s stellar classification, based on spectral class, is a G-type main sequence star (G2V), and is informally designated as a yellow dwarf, because its visible radiation is most intense in the yellow-green portion of the spectrum and although its color is white, from the surface of the Earth it may appear yellow because of atmospheric scattering of blue light.In the spectral class label, G2 indicates its surface temperature of approximately 5778 K (5505 ☌), and V indicates that the Sun, like most stars, is a main-sequence star, and thus generates its energy by nuclear fusion of hydrogen nuclei into helium. It is thought that almost all other stars form in this way. The central mass became increasingly hot and dense, eventually initiating thermonuclear fusion in its core. Most of the matter gathered in the center, while the rest flattened into an orbiting disk that would become the Solar System. The Sun formed about 4.6 billion years ago from the gravitational collapse of a region within a large molecular cloud. The remainder (1.69%, which nonetheless equals 5,628 times the mass of Earth) consists of heavier elements, including oxygen, carbon, neon and iron, among others. The luminosity of the star is the energy released per unit time. Chemically, about three quarters of the Sun’s mass consists of hydrogen, while the rest is mostly helium. The Sun, a G-type star with a main sequence lifetime of 10 billion years, is currently 5 billion years old about half way through its main sequence lifetime. It is almost perfectly spherical and consists of hot plasma interwovenwith magnetic fields. It has a diameter of about 1,392,684 km,about 109 times that of Earth, and its mass (about 2×10 30 kilograms, 330,000 times that of Earth) accounts for about 99.86% of the total mass of the Solar System. There are giant stars that are actually larger than some supergiant stars.The Sun is the star at the center of the Solar System. These stars are white to white-yellow with strong spectral absorption lines due to. The classification as a giant or supergiant star, however, is as much dependent upon the grouping of stars in the HR diagram as upon radial size. these are stars of spectral types B5 to F5 and have strong magnetic fields. These immense stars are accordingly termed supergiants. As most stars of this type are cooler and redder, the term red giant is often used.Ī similar comparison with an even brighter G star at M = –7.5 produces a size that is 310 times that of the Sun, or a radius of 220 million km, placing the photosphere at the orbit of Mars if this star were to replace the Sun in the solar system. It is because of the size of these objects that they are termed giant stars. Giant stars can also fall in the G-class (yellow giants), including. As seen from Earth, it would appear 15° in diameter. Some example G-type stars are Alpha Centauri and T Tauri (a pre-main-sequence star). If such a star were placed in the center of the solar system, its surface would be one‐third of the distance out to the planet Mercury. This temperature range gives the F-type stars a whitish hue when observed by the atmosphere. These stars have from 1.0 to 1.4 times the mass of the Sun and surface temperatures between 6,000 and 7,600 K. As the Sun has a radius of 700,000 km, the radius of the more luminous star is 22 million km. An F-type main-sequence star (F V) is a main-sequence, hydrogen -fusing star of spectral type F and luminosity class V. Relating the luminosity of the first star to the second,Ī ratio of 1000 in luminosity means the more luminous star must be √1000 = 31 times larger than the main sequence star. For example, L = σT 44πR 2, where R is the radius of the star. Stefan‐Boltzman's law allows the luminosity of each star to be expressed in terms of its surface temperature and surface area. By the definition of spectral type, both stars have the same surface temperature T, yet their luminosities L differ by 7.5 magnitudes or a factor of 1000 in luminosity. One could be a main sequence star with M = +5 and the other a giant star with M = –2.5. Two stars at the same spectral type, say type G, can have quite different brightnesses. SETI-The Search for Extraterrestrial Intelligence.T/F: The spectral type of a star tells us the star's mass and luminosity. T/F: All else being equal, the hotter a star is, the brighter it will be. T/F: A type B9 star is hotter than a type A0. Internal Structure Standard Solar Model T/F: Arcturus is absolute magnitude 0, so it is about 100X more luminous than our Sun.Interior Structure: Core, Mantle, Crust.Minor Objects: Asteroids, Comets, and More.Origin and Evolution of the Solar System.
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