Skrzynka do zadań specjalnych

Skrzynka : klop, Subskrybuj: RSS, Alias:

Same Plusy!

  • Niepodam.pl nie wymaga rejestracji, aktywacji, nie wysyła SPAMU!
  • Nie dostaniesz spamu na swoją prywatną skrzynkę E-mail
  • Nigdy nie usuniemy Twojej skrzynki i będziesz mógł przypomnieć sobie hasło do innej strony kiedy chcesz
  • Używając aliasów nikt inny nie będzie wiedział jakiego użyłeś loginu do naszego serwisu
  • Nowe! W dowolnym formularzu rejestracyjnym użyj adresu rozpoczynającego się na a_ (np. a_tomek@niepodam.pl) a Twój link aktywacyjny zostanie automatycznie kliknięty.

Hey, sending you a free bottle of probiotics (need your address)

<< Starsza wiadomość Nowsza wiadomość >>

Treść wiadomości:

Newsletter

If you wish to opt-out from our mailing list please visit here



Hey, sending you a free bottle of probiotics (need your address)







 

 

 

 

 

 






 

 





 
given in terms of an effective temperature, which is the temperature of an idealized black body that radiates its energy at the same luminosity per surface area as the star. Note that the effective temperature is only a representative of the surface, as the temperature increases toward the core. The temperature in the core region of a star is several million kelvins. The stellar temperature will determine the rate of ionization of various elements, resulting in characteristic absorption lines in the spectrum. The surface temperature of a star, along with its visual absolute magnitude and absorption features, is used to classify a star (see classification below). Massive main sequence stars can have surface temperatures of 50,000 K. Smaller stars such as the Sun have surface temperatures of a few thousand K. Red giants have relatively low surface temperatures of about 3,600 K; but they also have a high luminosity due to their large exterior surface area. Radiation The energy produced by stars, a product of nuclear fusion, radiates to space as both electromagnetic radiation and particle radiation. The particle radiation emitted by a star is manifested as the stellar wind, which streams from the outer layers as electrically charged protons and alpha and beta particles. Although almost massless, there also exists a steady stream of neutrinos emanating from the star's core. The production of energy at the core is the reason stars shine so brightly: every time two or more atomic nuclei fuse together to form a single atomic nucleus of a new heavier element, gamma ray photons are released from the nuclear fusion product. This energy is converted to other forms of electromagnetic energy of lower frequency, such as visible light, by the time it reaches the star's outer layers. The color of a star, as determined by the most intense frequency of the visible light, depends on the temperature of the star's outer layers, including its photosphere. Besides visible light, stars also emit forms of electromagnetic radiation that are invisible to the human eye. In fact, stellar electromagnetic radiation spans the entire electromagnetic spectrum, from the longest wavelengths of radio waves through infrared, visible light, ultraviolet, to the shortest of X-rays, and gamma rays. From the standpoint of total energy emitted by a star, not all components of stellar electromagnetic radiation are significant, but all frequencies provide insight into the star's physics. Using the stellar spectrum, astronomers can also determine the surface temperature, surface gravity, metallicity and rotational velocity of a star. If the distance of the star is found, such as by measuring the parallax, then the luminosity of the star can be derived. The mass, radius, surface gravity, and rotation period can then be estimated based on stellar models. (Mass can be calculated for stars in binary systems by measuring their orbital velocities and distances. Gravitational microlensing has been used to measure the mass of a single star.) With these parameters, astronomers can also estimate the age of the star. Luminosity The luminosity of a star is the amount of light and other forms of radiant energy it radiates per unit of time. It has units of power. The luminosity of a star is determined by its radius and surface temperature. Many stars do not radiate uniformly across their entire surface. The rapidly rotating star Vega, for example, has a higher energy flux (power per unit area) at its poles than along its equator. Patches of the star's surface with a lower temperature and luminosity than average are known as starspots. Small, dwarf stars such as our Sun generally have essentially featureless disks with only small starspots. Giant stars have much larger, more obvious starspots, and they also exhibit strong stellar limb darkening. That is, the brightness decreases towards the edge of the stellar disk. Red dwarf flare stars such as UV Ceti may also possess prominent starspot features
W celu usunięcia maila wpisz ten tekst: 0fa78a1a
Aby zaznaczyć ten mail jako spam wpisz ten tekst: 0fa78a1a

<< Starsza wiadomość Nowsza wiadomość >>
Ważne: nasze strony wykorzystują pliki cookies.

Bez tych plików serwis nie będzie działał poprawnie. W każdej chwili, w programie służącym do obsługi internetu, można zmienić ustawienia dotyczące cookies. Korzystanie z naszego serwisu bez zmiany ustawień oznacza, że będą one zapisane w pamięci urządzenia. Więcej informacji w Polityce prywatności.

Zapoznałem się z informacją