page_title: G-type main-sequence star
hierarchical_section_title: G-type main-sequence star
caption_attribution_description: English: The image was taken through a 80mm Vixen refractor mounted on a Super Polaris equatorial mounting. Sonnenfilter SF100 full aperture solar filter (bought from: http://astronomia.co.uk/index.php/accessories/filters/emc-solarfilter-sf100-59-71-mm.html) was used to reduce the light intensity. The film is used as a filter that goes over the aperture of the telescope making it safe to observe and image the Sun. The camera was a Canon 550D DSLR at prime focus. Exposure was 1/400 sec at ISO100. Русский: Фотография получена через телескоп-рефрактор «Vixen» диаметром апертуры 80 мм установленный на экваториальной монтировке «Super Polaris». Использован полноапертурный солнечный фильтр SF100 (купленный на сайте: http://astronomia.co.uk/index.php/accessories/filters/emc-solarfilter-sf100-59-71-mm.html). Фотоаппарат: Canon 550D DSLR установленный в главном фокусе. Экспозиция: 1/400 sec ISO 100. Время съёмки: 10:45, 27 Октября 2013. Общество популярной астрономии, секция Солнца, http://www.popastro.com/solar/solarobserving/chapter.php?id_pag=30. Автор: Geoff Elston.
context_page_description: A G-type main-sequence star, often called a yellow dwarf, or G dwarf star, is a main-sequence star of spectral type G. Such a star has about 0.84 to 1.15 solar masses and surface temperature of between 5,300 and 6,000 K., Tables VII, VIII. Like other main-sequence stars, a G-type main-sequence star is converting the element hydrogen to helium in its core by means of nuclear fusion. The Sun, the star to which the Earth is gravitationally bound in the Solar System, is an example of a G-type main-sequence star. Each second, the Sun fuses approximately 600 million tons of hydrogen into helium in a process known as the proton-proton chain, converting about 4 million tons of matter to energy. Besides the Sun, other well-known examples of G-type main-sequence stars include Alpha Centauri A, Tau Ceti, and 51 Pegasi.
  The term yellow dwarf is a misnomer, because G-type stars actually range in color from white, for more luminous types like the Sun, to only very slightly yellow for the less massive and luminous G-type main-sequence stars.
context_section_description: A G-type main-sequence star (Spectral type: G-V), often (and imprecisely) called a yellow dwarf, or G dwarf star, is a main-sequence star (luminosity class V) of spectral type G. Such a star has about 0.84 to 1.15 solar masses and  surface temperature of between 5,300 and 6,000 K., Tables VII, VIII. Like other main-sequence stars, a G-type main-sequence star is converting the element hydrogen to helium in its core by means of nuclear fusion. The Sun, the star to which the Earth is gravitationally bound in the Solar System, is an example of a G-type main-sequence star (G2V type). Each second, the Sun fuses approximately 600 million tons of hydrogen into helium in a process known as the proton-proton chain (4 hydrogens form 1 helium), converting about 4 million tons of matter to energy. Besides the Sun, other well-known examples of G-type main-sequence stars include Alpha Centauri A, Tau Ceti, and 51 Pegasi.
  The term yellow dwarf is a misnomer, because G-type stars actually range in color from white, for more luminous types like the Sun, to only very slightly yellow for the less massive and luminous G-type main-sequence stars. The Sun is in fact white, and its spectrum peaks in blue and green light, but it can often appear yellow, orange or red through Earth's atmosphere due to atmospheric Rayleigh scattering, especially at sunrise and sunset. In addition, although the term "dwarf" is used to contrast yellow main-sequence stars from giant stars, yellow dwarfs like the Sun outshine 90% of the stars in the Milky Way (which are largely much dimmer orange dwarfs, red dwarfs, and white dwarfs, the last being a stellar remnant).
  A G-type main-sequence star will fuse hydrogen for approximately 10 billion years, until it is exhausted at the center of the star. When this happens, the star expands to many times its previous size and becomes a red giant, such as Aldebaran (or Alpha Tauri).  Eventually the red giant sheds its outer layers of gas, which become a planetary nebula, while the core rapidly cools and contracts into a compact, dense white dwarf.
caption: The Sun, a typical example of a G-type main-sequence star.
exif: {"Image ImageWidth": "3846", "Image ImageLength": "2564", "Image BitsPerSample": "[8, 8, 8]", "Image PhotometricInterpretation": "2", "Image Make": "Canon", "Image Model": "Canon EOS 550D", "Image Orientation": "Horizontal (normal)", "Image SamplesPerPixel": "3", "Image XResolution": "72", "Image YResolution": "72", "Image ResolutionUnit": "Pixels/Inch", "Image Software": "Adobe Photoshop CS6 (Macintosh)", "Image DateTime": "2014:08:27 15:45:42", "Image YCbCrPositioning": "Co-sited", "Image ExifOffset": "292", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail XResolution": "72", "Thumbnail YResolution": "72", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "1158", "Thumbnail JPEGInterchangeFormatLength": "5850", "EXIF ExposureTime": "1/400", "EXIF FNumber": "0", "EXIF ExposureProgram": "Manual", "EXIF ISOSpeedRatings": "100", "EXIF ExifVersion": "0221", "EXIF DateTimeOriginal": "2013:10:27 10:45:09", "EXIF DateTimeDigitized": "2013:10:27 10:45:09", "EXIF ComponentsConfiguration": "YCbCr", "EXIF ShutterSpeedValue": "69/8", "EXIF ApertureValue": "2147483648", "EXIF ExposureBiasValue": "0", "EXIF MeteringMode": "Pattern", "EXIF Flash": "Flash did not fire, compulsory flash mode", "EXIF FocalLength": "0", "EXIF SubSecTime": "00", "EXIF SubSecTimeOriginal": "00", "EXIF SubSecTimeDigitized": "00", "EXIF FlashPixVersion": "0100", "EXIF ColorSpace": "sRGB", "EXIF ExifImageWidth": "2328", "EXIF ExifImageLength": "2328", "Interoperability InteroperabilityIndex": "R98", "Interoperability InteroperabilityVersion": "[48, 49, 48, 48]", "EXIF InteroperabilityOffset": "1028", "EXIF FocalPlaneXResolution": "1036800/181", "EXIF FocalPlaneYResolution": "691200/119", "EXIF FocalPlaneResolutionUnit": "2", "EXIF CustomRendered": "Normal", "EXIF ExposureMode": "Manual Exposure", "EXIF WhiteBalance": "Auto", "EXIF SceneCaptureType": "Standard"}