AST101H1 Lecture Notes - Lecture 8: Photosphere, Chromosphere, Cool Air

• School: UTSG
• Department: Astronomy & Astrophysics
• Course: AST101H1
• Professor: Bryan Gaensler

Document Summary

Diameter: 1,392,000km (109 times the diameter of earth) Composition (by mass): 70% hydrogen, 28% helium, 1% oxygen, 0. 4% carbon, 0. 6% heavier elements. Rotation rate: 25 days (at the equator) to 30 days (at the poles) Temperature: 5500c (average), 3700c (sunspots), 15 million c (centre) Heat & light travel outward from the core: convective zone. Lots of churning: hot air rising, cool air falling: photosphere. (cid:862)g(cid:396)a(cid:374)ulated(cid:863) with each granule being 1000km across and lasting 5 10 mins. Hot areas rising, dark (colder) areas sinking: corona. Halo of gas above photosphere and chromosphere. Seen only during total eclipse of the sun and approx. U(cid:374)"s (cid:373)ass (cid:272)o(cid:374)tai(cid:374)s (cid:373)o(cid:396)e tha(cid:374) e(cid:374)ough e(cid:374)e(cid:396)gy to a(cid:272)(cid:272)ou(cid:374)t fo(cid:396) (cid:271)illio(cid:374)s of yea(cid:396)s of su(cid:374)shi(cid:374)e. mass itself contains an enormous amount of potential energy and the sun converts this energy to thermal energy. Balance between the outward push of internal gas pressure and the inward pull of gravity.