Observing the Sun. Corona: EUV; X-rays Chromosphere: H , UV, EUV Photosphere: near UV, Visible...

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Observing the Sun

Transcript of Observing the Sun. Corona: EUV; X-rays Chromosphere: H , UV, EUV Photosphere: near UV, Visible...

Page 1: Observing the Sun. Corona: EUV; X-rays Chromosphere: H , UV, EUV Photosphere: near UV, Visible light, infra-red.

Observing the Sun

Page 2: Observing the Sun. Corona: EUV; X-rays Chromosphere: H , UV, EUV Photosphere: near UV, Visible light, infra-red.

Observing the Sun

Corona: EUV; X-rays

Chromosphere: H, UV, EUV

Photosphere: near UV, Visible light, infra-red

Page 3: 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

Page 4: Observing the Sun. Corona: EUV; X-rays Chromosphere: H , UV, EUV Photosphere: near UV, Visible light, infra-red.

Observing the SunNear Infrared

Helium I (10830 Å) weaker in coronal holes strong in active regions, filaments

National Solar Observatory (Kitt Peak)

Page 5: Observing the Sun. Corona: EUV; X-rays Chromosphere: H , UV, EUV Photosphere: near UV, Visible light, infra-red.

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

Page 6: Observing the Sun. Corona: EUV; X-rays Chromosphere: H , UV, EUV Photosphere: near UV, Visible light, infra-red.

Observing the SunVisible light: filtered

Calcium K line 3933.7 ÅChromosphere: plages, supergranules,..

National Solar Observatory, Sacramento Peak in Sunspot, New Mexico

Page 7: Observing the Sun. Corona: EUV; X-rays Chromosphere: H , UV, EUV Photosphere: near UV, Visible light, infra-red.

Observing the SunVisible light: filtered

H-alpha 6562.8 Å, 0.01 MK

Chromosphere: filaments, plages,..

(e.g. Big Bear Solar Observatory)

Page 8: Observing the Sun. Corona: EUV; X-rays Chromosphere: H , UV, EUV Photosphere: near UV, Visible light, infra-red.

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

Page 9: Observing the Sun. Corona: EUV; X-rays Chromosphere: H , UV, EUV Photosphere: near UV, Visible light, infra-red.

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

Page 10: Observing the Sun. Corona: EUV; X-rays Chromosphere: H , UV, EUV Photosphere: near UV, Visible light, infra-red.

Gamma-ray observations

solar flares

RHESSI

Page 11: Observing the Sun. Corona: EUV; X-rays Chromosphere: H , UV, EUV Photosphere: near UV, Visible light, infra-red.

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)

Page 12: Observing the Sun. Corona: EUV; X-rays Chromosphere: H , UV, EUV Photosphere: near UV, Visible light, infra-red.

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

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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/)

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The latest addition to solar observatories

• NASA’s STEREO spacecraft launched on Oct 25 2006

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Page 16: Observing the Sun. Corona: EUV; X-rays Chromosphere: H , UV, EUV Photosphere: near UV, Visible light, infra-red.

3-D with STEREO

Page 17: Observing the Sun. Corona: EUV; X-rays Chromosphere: H , UV, EUV Photosphere: near UV, Visible light, infra-red.

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