lacaille 8760 is the closest red giant star to earth.
what is the closest red giant star to earth?
lacaille 8760
bullet::::- mimosa or beta crucis is a blue-hued giant star of magnitude 1.3, and lies 353 light-years from earth. it is a beta cephei-type variable star with a variation of less than 0.1 magnitudes.





























bullet::::- gacrux or gamma crucis is an optical double star. the primary is a red-hued giant star of magnitude 1.6, 88 light-years from earth, and is one of the closest red giants to earth. its secondary component is magnitude 6.5, 264 light-years from earth.
crux
once a star has evolved sufficiently to become a red giant, its circumstellar habitable zone will change dramatically from its main-sequence size. for example, the sun is expected to engulf the previously-habitable earth as a red giant. however, once a red giant star reaches the horizontal branch, it achieves a new equilibrium and can sustain a new circumstellar habitable zone, which in the case of the sun would range from 7 to 22 au. at such stage, saturn's moon titan would likely be habitable in earth's temperature sense. given that this new equilibrium lasts for about 1 gyr, and because life on earth emerged by 0.7 gyr from the formation of the solar system at latest, life could conceivably develop on planetary mass objects in the habitable zone of red giants. however, around such a helium-burning star, important life processes like photosynthesis could only happen around planets where the atmosphere has carbon dioxide, as by the time a solar-mass star becomes a red giant, planetary-mass bodies would have already absorbed much of their free carbon dioxide. moreover, as ramirez and kaltenegger (2016) showed, intense stellar winds would completely remove the atmospheres of such smaller planetary bodies, rendering them uninhabitable anyway. thus, titan would not be habitable even after the sun becomes a red giant. nevertheless, life need not originate during this stage of stellar evolution for it to be detected. once the star becomes a red giant, and the habitable zone extends outward, the icy surface would melt, forming a temporary atmosphere that can be searched for signs of life that may have been thriving before the start of the red giant stage.
circumstellar habitable zone