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Distances -- stellar parallax
STELLAR PARALLAX
“APPARENT VISUAL MAGNITUDES”
Sun:
m =
Moon:
Venus:
Mars:
Sirius:
Vega:
Antares:
Polaris:
-27
-10
-4
-2.5
-1.4
0.0
1.0
2.3
“APPARENT VISUAL MAGNITUDES”
BRIGHTEST STAR (SIRIUS):
m = -1.4
20th BRIGHTEST STAR:
+1.5
FAINTEST VISIBLE:
... about 6.5
WITH BINOCULARS:
about 8
6-INCH TELESCOPE:
about 12
PLUTO:
14
LIMIT WITH MODERN DETECTORS
ON BIG TELESCOPES:
20 -- 28
“APPARENT VISUAL MAGNITUDES”
BRIGHTEST STAR (SIRIUS):
m = -1.4
20th BRIGHTEST STAR:
+1.5
FAINTEST VISIBLE:
... about 6.5
WITH BINOCULARS:
about 8
6-INCH TELESCOPE:
about 12
PLUTO:
14
LIMIT WITH MODERN DETECTORS
ON BIG TELESCOPES:
20 -- 28
Atomic Spectra – spectra of the elements
Kirchoff’s Laws
The Spectra of the Stars and Spectral Classification
Early classification – the
Harvard system
OBAFGKM -- a temperature sequence – decreasing
Binary Stars – Weighing and Measuring the Stars
> 50% of all stars are multiple
Three Types
Visual
Eclipsing – light curve
Spectroscopic –
velocity curve
The HR Diagram
Relative Sizes
The Largest Stars – Red Supergiants