例句與造句

1. It is located at the center of a planetary nebula and is believed to currently be in thermal instability and within its final shell helium flash phase.
2. Stars with below 8 9 Solar masses never reach high enough core temperature to burn carbon, instead ending their lives as carbon-oxygen white dwarfs after shell helium flashes gently expel the outer envelope in a planetary nebula.
3. During these " shell helium flashes ", the mass loss from the star is significant, and after many shell helium flashes, an AGB star is transformed into a hot white dwarf and its atmosphere becomes material for a planetary nebula.
4. During these " shell helium flashes ", the mass loss from the star is significant, and after many shell helium flashes, an AGB star is transformed into a hot white dwarf and its atmosphere becomes material for a planetary nebula.
5. Variable star observers Janet Mattei and Grant Foster proposed that the star had just undergone a shell helium flash & ndash; a point at which " the helium shell around the dense core of the star reaches a critical mass and ignites ", which " influences the star's pulsation via changes in surface luminosity and radius ".
6. It's difficult to find shell helium flash in a sentence. 用shell helium flash造句挺難的