PG1159 star
PG1159 star (after the star PG 1159-035 , in the Palomar-Green- screening was discovered) refers to a special class of stars that are in their development between the red giant and the final white dwarf are stage created. In February 2007 about three dozen objects of this type were known.
About 10 percent of all white dwarfs manage to ignite the helium fusion one last time ( helium flash ), and thus reach the giant stage again before they finally burn out into a white dwarf. PG1159 stars are in this last development step and are characterized by the special chemical composition of their atmosphere : in contrast to other stars, they contain almost no hydrogen , but are dominated by helium , carbon and oxygen .
The surface temperatures of PG1159 stars are extremely high at 70,000 to 200,000 K. The PG1159 star with the catalog designation H1504 + 65 is the hottest known star at 200,000 K and made it into the Guinness Book of Records in 2004 .
See also
swell
- K. Werner, T. Rauch .: The rebirth of the red giants . In: Stars and Space . 2/2007, Spektrum Verlag, ISSN 0039-1263
- International team of researchers led by Tübingen discovers an unusual pair of double stars. Archived from the original on September 30, 2007 ; accessed on December 31, 2015 .