our sun. iii. present and future (1993apj_418_475s)

Our Sun. III. Present and Future

(1993ApJ_418_475s)

Jae Gyu, Byeon

Contents

• Methods– Values of M, R, L, and t– Opacities– Presolar Helium and the Mixing Length– Mass Loss

• Results– The Sun’s evolution in the HR diagram– The Sun’s Mass Loss– Convection– The Sun’s Radial Excursions

• Conclusions

Methods

• Values of M⊙, R⊙, L⊙, and t⊙

– The solar mass is M⊙ = 1.9891 × 1033 g

– The solar radius at an optical depth of 0.001 is R⊙ = 6.9598 × 1033 cm

– The Solar luminosity L⊙ = 3.854 × 1033 erg s-1

– T⊙ = 4.55 Gyr

• Opacities– Use the Los Alamos Opacity from Keady(1985)

– At low temperatures, use the molecular opacities by Keady

– Modify recent molecular opacities of Sharp(1992)

Methods

• Presolar Helium and the Mixing Length– Presolar helium abundance, Y = 0.274– Mixing Length parameter, α = 2.10– Metallicity Z = 0.01954

• Mass Loss

– η is the mass-loss parameter– Normalized from the RGB mass loss inferred from (low mass) glob

ular cluster horizontal branch stars– Solar mass loss of 0.275 M⊙ on the RGB and 0.184 M⊙

on the AGB

The Sun’s evolution in the HRD

The Sun’s evolution in the HRD

The Sun’s Mass Loss

Convection

The Sun’s Radial Excursions