Heliophysics is the study of the effects of the Sun on the Solar System. This encompasses everything we have learned so far in ESS205 and more

figures from HELIOPHYSICS I, II and III PLASMA PHYSICS OF THE LOCAL COSMOS edited by CAROLUS J. SCHRIJVER Lockheed Martin Advanced Technology Center and GEORGE L. SISCOE Boston University 2010 Heliophysics has a rich history of interpretations, story and folklore about the sun and its effects on the planets. Folklore and the Aurora Robert H. Holzworth II

Holzworth, R. H., Folklore and the Aurora, Trans. Am. Geophys. Union, 56 (10) p. 686-9, 1975. [reprinted in: History of Geophysics, V.1, Ed. C. S. Gillmor, Am. Geophys. Union, Washington DC, p.41-4, 1984]

Northern Lights woodcut. Adapted from illustration by Fridjof Nansen based on a sketch from 1883 We talked about how to model the physics of the sun, but how did it start?

25+ years of Hubble Images: http://hubblesite.org/ This turbulent cosmic pinnacle lies within a tempestuous stellar nursery called the Carina Nebula, located 7,500 light- years away in the southern constellation Carina. Nestled inside this dense mountain are fledgling stars. Long streamers of gas can be seen shooting in opposite directions off the pedestal at the top of the image NASA Hubble Image ABOUT THIS IMAGE: This craggy fantasy mountaintop enshrouded by wispy clouds looks like a bizarre landscape from Tolkien's "The Lord of the Rings" or a Dr. Seuss book, depending on your imagination. The NASA Hubble Space Telescope image, which is even more dramatic than fiction, captures the chaotic activity atop a three-light-year-tall pillar of gas and dust that is being eaten away by the brilliant light from nearby bright stars. The pillar is also being assaulted from within, as infant stars buried inside it fire off jets of gas that can be seen streaming from towering peaks. This turbulent cosmic pinnacle lies within a tempestuous stellar nursery called the Carina Nebula, located 7,500 light-years away in the southern constellation Carina. The image celebrates the 20th anniversary of Hubble's launch and deployment into an orbit around Earth. Scorching radiation and fast winds (streams of charged particles) from super-hot newborn stars in the nebula are shaping and compressing the pillar, causing new stars to form within it. Streamers of hot ionized gas can be seen flowing off the ridges of the structure, and wispy veils of gas and dust, illuminated by starlight, float around its towering peaks. The denser parts of the pillar are resisting being eroded by radiation much like a towering butte in Utah's Monument Valley withstands erosion by water and wind. Nestled inside this dense mountain are fledgling stars. Long streamers of gas can be seen shooting in opposite directions off the pedestal at the top of the image. Another pair of jets is visible at another peak near the center of the image. These jets (known as HH 901 and HH 902, respectively) are the signpost for new star birth. The jets are launched by swirling disks around the young stars, which allow material to slowly accrete onto the stars' surfaces. Hubble's Wide Field Camera 3 observed the pillar on Feb. 1-2, 2010. The colors in this composite image correspond to the glow of oxygen (blue), hydrogen and nitrogen (green), and sulfur (red).

How do we relate the absolute magnitude of these stars to the energy and mass of our sun?

In addition to their apparent magnitude, we need to know how far away they are. Cepheid Variable stars have a brightness which is related to the period. So, observing similar period pulsating Cepheid-type stars can give an idea about distance away. The periodicity comes from the fact that He ions have a different opacity depending on the ionization state (one or two electrons). As the gas near the photosphere heats up, He ionization is affected so more of the opaque ion is formed. This heats the star, which expands, and as the outer gas cools with expansion, the other less opaque form of He ion dominates, cooling the star, which constricts and it starts over again. Once the star is formed and stabilized (like our sun on the Main sequence) we can start thinking about the influence of the sun and its emitted plasma (Solar wind) on the planets and other solar system bodies. Turbulence in Space Plasmas, and the relation between plasma and magnetic field

Mothers Day (last year) Aurora from turbulent solar wind stream hitting the earth

(see http://spaceweather.com )

Radiation Belts

But, how stable is that magnetic field?

SUN

Note: 342 W/m2 is average over a whole day (less than the solar constant) Heliospheric Physics brings in the importance of plasmas and magnetic fields to the evolution of the bodies in the solar system

• Additional figs below