Temperatures of stars

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Temperatures of stars
Gert Schooten Agnieten College
loc. Carolus Clusius Zwolle, The Netherlands
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Content of the workshop

• Determining the temperature of a star-
  professional method- didactic point of view
• simple hands-on tools classroom experience

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Gathering knowledge

• Light, light and nothing but light
• Watching with (special sun)glasses

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Analysing light
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Classroom (1)
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Spectroscope experiment

• Make drawings of
• - spectrum of the sun - spectrum of a light
  bulb- spectrum of a fluorescent lightNB -
  mind colour and intensity - mind temperature
  of the filament

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Classroom (2)
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Splitting light
You can make histograms of it !
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Histograms of spectra
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Spectrum as a fingerprint
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Conclusion

• Light bulb- a continuous spectrum as
  sunlight- as the voltage increases more
  light more colours more heat ??
• Watching gt collecting radiation

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EM-spectrum (1)
Shorter wavelenghts, more energy
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EM spectrum (2)

• wavelength frequency constant
• ?f c with c 3,0108 m/s (velocity of
  light)

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Planck-curves
histogram
continuous line
Notice the different sequence of colours /
wavelength !
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Excel-sheet
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Excel-curves
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Thermal radiation

• strongly depends on the temperature
• displacement of the maximum

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Starspectrum
To take this spectrum costs a lot of time, so
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Filter experiment

• Use filter and spectroscoop to look at -
  spectrum of the sun - spectrum of a light
  bulb - spectrum of a fluorescent light

Transmission mainly in the wavelength area!
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Professional filters
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Blue and Red stars
large colour number small
colour number
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Constructing a gauge curve

• Determine the colour number for each temperature
• Make a diagram (colour number, temperatuur)

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Gauge curve
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Globular cluster M12
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Milky Way
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Data M12

• Ophiuchus (Oph)
• coördinates- RA 16 h 47 m- Dec 0157
• distance 18.000 ly
• diameter 75 ly
• velocity - 16 km/s

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B- and V-band of M12
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Determining temperatures

• gauge on a star gt diameter
• B-band stars and V-band stars
• calculate the colour number
• deteremine the temperature with your gauge diagram

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HR-diagram of M12