Blue giant Bellatrix
In astronomy, a blue giant is a hot star with a luminosity class of III (giant) or II (bright giant). In the standard Hertzsprung–Russell diagram, these stars lie above and to the right of the main sequence.
In astronomy, a blue giant is a hot star with a luminosity class of III (giant) or II (bright giant). In the standard Hertzsprung–Russell diagram, these stars lie above and to the right of the main sequence.
Green NGC 6572
If you happen to be in the neighborhood of Ophiuchus, look for a brilliant green "star", NGC 6572, off the giant's right shoulder. See attached Starry Night screenshot for general location. Of course, this is no star. Rather, it is a planetary nebula.
If you happen to be in the neighborhood of Ophiuchus, look for a brilliant green "star", NGC 6572, off the giant's right shoulder. See attached Starry Night screenshot for general location. Of course, this is no star. Rather, it is a planetary nebula.
Red Giants Mira
Mira was the first variable star to be discovered (discovery 1596, variability 1639). Mira or Omicron Ceti is a red giant, which irregularly pulsates very strong. When all hydrogen in the core of a star is spent the hydrogen fusion migrates to its outer layers. The hull of the star is driven outside by the radiation pressure, the star increases its diameter up to a hundred times. So far outside the surface cools down to 2000 - 4000 kelvin and shines red. Although the surface temperature is lower than before, the star has become considerably more luminous than before and produces by far more energy. Red giants very often pulsate and in doing so change their brightness.
Champagne Supernova
Thermonuclear supernovae were thought to occur only when white-dwarf stars of a certain mass explode. The discovery of a supernova that is way over the mass limit might require a reworking of the model.
Thermonuclear supernovae were thought to occur only when white-dwarf stars of a certain mass explode. The discovery of a supernova that is way over the mass limit might require a reworking of the model.
White Dwarf
The dead remainder of a normal sized star, its former core. This has about the size of the Earth, its mass is below 1.44 solar masses. So it has an enormous average density, a hundered thousand times more than this of a normal star. Young white dwarfs are still surrounded by the rest of their former hull, so called planetary nebulae. This name they have got because in small telescopes they look like planets, but have nothing to do with planets.
The dead remainder of a normal sized star, its former core. This has about the size of the Earth, its mass is below 1.44 solar masses. So it has an enormous average density, a hundered thousand times more than this of a normal star. Young white dwarfs are still surrounded by the rest of their former hull, so called planetary nebulae. This name they have got because in small telescopes they look like planets, but have nothing to do with planets.
Our Yellow Sun
Stars as our Sun. With three quarters solar mass a star shines orange, with three times it is white. The surface temperature varies according to this between 4000 and 10000 kelvin. Our Sun has 5770 kelvin and therefore is yellow.
Stars as our Sun. With three quarters solar mass a star shines orange, with three times it is white. The surface temperature varies according to this between 4000 and 10000 kelvin. Our Sun has 5770 kelvin and therefore is yellow.
Note:
Bintang yang kelap kelip dilangit malam tempat kita tinggal sekarang, sebenarnya adalah matahari. Jadi diluar angkasa sana, bertebaran beribu ribu matahari seperti matahari yang tiap pagi dan siang menyengat kita dengan sinarnya,dan malam hari tetap menyinari kita dengan pantulan cahayanya kebulan lalu kebumi. Dan matahari matahari ini memiliki umur yang berbeda beda. Karena itulah bintang bintang terlihat kelap kelip. Semakin muda umurnya dia akan berwarna kebiruan (yang artinya juga semakin panas). Dan kuning ke-orange seperti matahari kita, ya umurnya bisa dibilang masih remaja 20-an lah. Kalau warnanya merah, berarti bintang itu sudah menua. Yang sampai pada akhirnya menjadi warna putih...bintang mati...dan bila si bintang mati ini meledak, terjadilah champagne supernova (macam lagunya Oasis ya *grin*).
Bintang yang kelap kelip dilangit malam tempat kita tinggal sekarang, sebenarnya adalah matahari. Jadi diluar angkasa sana, bertebaran beribu ribu matahari seperti matahari yang tiap pagi dan siang menyengat kita dengan sinarnya,dan malam hari tetap menyinari kita dengan pantulan cahayanya kebulan lalu kebumi. Dan matahari matahari ini memiliki umur yang berbeda beda. Karena itulah bintang bintang terlihat kelap kelip. Semakin muda umurnya dia akan berwarna kebiruan (yang artinya juga semakin panas). Dan kuning ke-orange seperti matahari kita, ya umurnya bisa dibilang masih remaja 20-an lah. Kalau warnanya merah, berarti bintang itu sudah menua. Yang sampai pada akhirnya menjadi warna putih...bintang mati...dan bila si bintang mati ini meledak, terjadilah champagne supernova (macam lagunya Oasis ya *grin*).
Cakep....
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