The Spectrum

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Huggins and Miller, Proc. Roy. Soc. (1863)

Sun

Betelgeuse

Sirius

Aldebaran

The stars were undoubtedly suns after the order of our sun*…

—Huggins (1897)

*What was it that Giordano Bruno had conjectured?

Slide 58

Interpreting nebular spectra

Huggins and Huggins, Proc. Roy. Soc. (1889)

Remember: these are hand-drawn spectragrams

Slide 59

Other Stellar Mysteries

Huggins observed the planetary nebula 37. H IV Draconis

… after a few moments of hesitation, I put my eye to the spectroscope. Was I not about to look into a secret place of creation? . I looked into the spectroscope. No spectrum such as I expected! A single bright line only!

Slide 60

The bright line was something new in the spectrum

Huggins called it nebulium

In a planetary nebula, ionized oxygen and other elements are blasted off a giant star

This is the line ionized oxygen makes, not reproducible in 19th century chemistry labs

Slide 61

Slide 62

Margaret Lindsay Huggins (1848-1915)

Married William when he was around 50

Margaret was an accomplished photographer

She designed photographic equipment for use with the spectroscope

Huggins laboratory notebooks also become much more organized and informative due to Margaret

Slide 63

William Huggins

in the

Tulse Hill Observatory

(ca. 1905)

Slide 64

The Modern Variety of Data

The data plots don’t necessarily look like rainbows

Infrared, gamma-ray, microwave, x-ray spectra are all valuable data

Slide 65

The discovery of helium

P.J.C. Janssen (Fr) and J. Norman Lockyer (UK) independently determined that the solar atmosphere could be studied spectroscopically

Consequently, the bright orange ‘D’ line that was assumed to be sodium turned out to be an indication of a new element

Helium isolated in the laboratory in 1895 by William Ramsay

Slide 66

VVVVVrrrrroooooommmm

Spectra can also tell Astronomers if a distant object is moving towards or away from us

And also how fast it is spinning

The technique is to use the Doppler Effect to see how the spectral lines are affected