Astrophysics I (8025)
Intro. Astrophysics I (4025)
A Survey of Astrophysics
(excluding planetary)
Stellar Brightnesses and Surface Temperatures
Blackbody Radiation
So hνmax ≈ 2.82 kT or
 max
T
 5.88x1010 Hz K 1
Doing the same in wavelength units: max  2900  m
T
Stellar Sizes
Model of Altair,
based on data
from the Navy
Prototype
Optical
Interferometer
(Peterson et al.
2006, ApJ,
636, 1087)
Stellar Masses
β Cyg = “Albireo”
Stellar Spectra
...no longer confined to anthropocentric visible wavelengths...
7
Most Important
Diagram #1:
HR Diagram
Empty Space is NOT Empty The Interstellar Medium
What do these mean??
The Birth of Stars
and their deaths.....
The Milky Way Galaxy
and others.....
The Universe
Active
Galaxies
Most Important
Diagram #2:
Hubble
Diagram
Baby Picture of the Universe
Locating Information
• NASA’s Astrophysics Data System (ADS):
http://adswww.harvard.edu/ and particularly
http://adsabs.harvard.edu/abstract_service.html
• SIMBAD: http://simbad.harvard.edu/simbad/ and
http://simbad.u-strasbg.fr/simbad/ (there are 2 sites)
• NOTE: VIRTUALLY ALL ELECTRONIC CATALOGS
TODAY SEARCH SIMBAD FOR RESOLVING STAR
NAMES AND GETTING THEIR COORDINATES. If
SIMBAD is down, you may be out of luck!
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