| The spectacular light curves and complex interactions of Red Novae(RNe) are very important and attractive phenomena. The observational data of V1309 Sco and V838 Mon suggested that RNe may originate from binary merger. If it is true, RNe offer a good chance for our understanding of binary merger. Assuming that RNe result from binary mergers and using recent observational data, we carry out a detail investigation of RNe population.Firstly, according to the special observed characteristics of RNe, we analyze and fit evolution of the luminosity and the temperature.Secondly, we compute the evolution tracks of V838 Mon, V1309 Sco and normal stars with masses between 1 M⊙and 40 M⊙. The evolution tracks of RNe are very different from those of normal stars. A RN finally evolves to a star near the Hayashi line. Mass of a RN is equivalent to the total mass of two components in progenitor binary. If a RN has a similar mass with a zero-age main sequence star, the RNe and the star will evolve to the vicinity of a Hayashi line.Then, using a population synthesis code, we calculate the Galactic birthrate of RNe. We estimate that the Galactic birthrate of RNe is 0.14 yr-1. About 62% of them are merged by giants and main sequence stars, about 22% originate from the merger of white dwarfs and main sequence stars, about 11% of them are powered by the merger of Hertzsprung gap stars and main sequence stars, about 3% of them come from the merger of main sequence stars and main sequence stars, and any other binary mergers are negligible.Finally, we study the properties of progenitor systems of RNe. We find that the primaries(donors) are mainly low-mass stars, and the orbital periods are usually about 2 ~ 62 days. |
