Observing the Sun. Corona: EUV; X-rays Chromosphere: H , UV, EUV Photosphere: near UV, Visible...
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Transcript of Observing the Sun. Corona: EUV; X-rays Chromosphere: H , UV, EUV Photosphere: near UV, Visible...
Observing the Sun
Observing the Sun
Corona: EUV; X-rays
Chromosphere: H, UV, EUV
Photosphere: near UV, Visible light, infra-red
Observing the SunRadio Waves
Solar flare on October 29, 200117 GHz, Nobeya Radioheliograph
Observing the SunNear Infrared
Helium I (10830 Å) weaker in coronal holes strong in active regions, filaments
National Solar Observatory (Kitt Peak)
Observing the SunVisible light: all wave lengths
All wave lengths
Photosphere: visible surface of the Sun sunspots, faculae
Catania Astrophysical Observatory in Italy
sharp boundary!
density
less material, less dense
opaque to transparent
0I I e
temperature
Observing the SunVisible light: filtered
Calcium K line 3933.7 ÅChromosphere: plages, supergranules,..
National Solar Observatory, Sacramento Peak in Sunspot, New Mexico
Observing the SunVisible light: filtered
H-alpha 6562.8 Å, 0.01 MK
Chromosphere: filaments, plages,..
(e.g. Big Bear Solar Observatory)
Observing the SunUltraviolet
Fe IX, 171 Å1.3 MK
Fe XII, 195 Å1.6 MK
Layer of the Sun: upper chromosphere, lower corona
Temperature: ~MK
Active regions, loops, flares, ..
Wavelength: ~10-~8 m
e.g. SOHO/EIT
Helium II 304 Å, ~0.1 MK
Observing the SunX-rays
Satellites: e.g. Yohkoh, Trace
Active regions, coronal loops, flares
Dark areas: coronal holes
Layer of the Sun: corona
Temperature: 2-4 MK
Wavelength: ~10-9 m
Gamma-ray observations
solar flares
RHESSI
Magnetograms
line-of-sight component of magnetic flux at the photosphere.
The fields are measured by Zeeman splitting in a suitable magnetically sensitive absorption line (e.g. Ca K line)
National Solar Observatory (Kitt Peak)
White-light corona
“artificial” solar eclipse
Plane of the sky projection
Coronagraph
- Skylab (first CME): 1973-1974- Solwind: 1979-1980; 1984-1985 - SMM: 1980; 1984-1989- SOHO/LASCO: 1996 →- STEREO/SECCHI 2007 →
+ ground based coronagraphs MK3 Mauna Loa Solar Observatory
Observing the Sun
Some on-going missions:
• RHESSI: particle acceleration; solar flares; soft X-rays to gamma rays; launched February 2002
• TRACE: corona and transition region; X-ray and EUV; launched April 1998
• HINODE: solar magnetic fields; EUV, X-rays, optical telescope; launched September 2002
• SOHO: various instruments (see e.g. http://soho.esac.esa.int/about/instruments.html) launched December 1995• SDO (Solar Dynamic Observatory): launched 2010 (see e.g. http://sdo.gsfc.nasa.gov/)
The latest addition to solar observatories
• NASA’s STEREO spacecraft launched on Oct 25 2006
3-D with STEREO
An encounter with a comet
STEREO-A records a CME ripping off comet Encke’s tail in April 20, 2007
See story and the movie:
http://science.nasa.gov/headlines/y2007/01oct_encke.htm