R Leonis

R Leonis is a red giant Mira-type variable star in the constellation Leo.

The apparent magnitude of R Leonis varies between 4.31 and 11.65 with a period of 312 days. At maximum it can be seen with the naked eye, while at minimum a telescope of at least 7 cm is needed. The star's effective temperature is estimated between 2930 and 3080 kelvins and radius spans between 320 and 350 solar radii (as large as 1.36–1.5 astronomical units, roughly Mars's orbital zone).

Read more about R Leonis:  A Planetary System?