Wavelength flux Spectral energy distributions of bright stars can be used to derive effective...
-
date post
20-Dec-2015 -
Category
Documents
-
view
217 -
download
1
Transcript of Wavelength flux Spectral energy distributions of bright stars can be used to derive effective...
![Page 1: Wavelength flux Spectral energy distributions of bright stars can be used to derive effective temperatures Ay 123 Lecture I - Physical Properties.](https://reader033.fdocuments.net/reader033/viewer/2022042821/56649d4b5503460f94a27e4b/html5/thumbnails/1.jpg)
wavelengthflux
Spectral energy distributions of bright stars can be used to derive effective temperatures
Ay 123 Lecture I - Physical Properties
![Page 2: Wavelength flux Spectral energy distributions of bright stars can be used to derive effective temperatures Ay 123 Lecture I - Physical Properties.](https://reader033.fdocuments.net/reader033/viewer/2022042821/56649d4b5503460f94a27e4b/html5/thumbnails/2.jpg)
Wavelength(m)
fluxTeff
Model atmospheres of varying [Teff, g] used to fit data
![Page 3: Wavelength flux Spectral energy distributions of bright stars can be used to derive effective temperatures Ay 123 Lecture I - Physical Properties.](https://reader033.fdocuments.net/reader033/viewer/2022042821/56649d4b5503460f94a27e4b/html5/thumbnails/3.jpg)
Stellar Spectral Energy Distributions
Wavelength(Å)
flux
![Page 4: Wavelength flux Spectral energy distributions of bright stars can be used to derive effective temperatures Ay 123 Lecture I - Physical Properties.](https://reader033.fdocuments.net/reader033/viewer/2022042821/56649d4b5503460f94a27e4b/html5/thumbnails/4.jpg)
Spectral Classification
Diagnostic spectral lines act as independent measures of temperature in stellar atmosphere provided surface gravity is known
![Page 5: Wavelength flux Spectral energy distributions of bright stars can be used to derive effective temperatures Ay 123 Lecture I - Physical Properties.](https://reader033.fdocuments.net/reader033/viewer/2022042821/56649d4b5503460f94a27e4b/html5/thumbnails/5.jpg)
Stellar Spectra: Giants vs Dwarfs
G
K
Stars are a 2-D sequence!
Giants are slightly cooler than dwarfs of a similar spectral class with redder continua. This is because line strengths depend on Teff and g
![Page 6: Wavelength flux Spectral energy distributions of bright stars can be used to derive effective temperatures Ay 123 Lecture I - Physical Properties.](https://reader033.fdocuments.net/reader033/viewer/2022042821/56649d4b5503460f94a27e4b/html5/thumbnails/6.jpg)
Luminosity Classes
![Page 7: Wavelength flux Spectral energy distributions of bright stars can be used to derive effective temperatures Ay 123 Lecture I - Physical Properties.](https://reader033.fdocuments.net/reader033/viewer/2022042821/56649d4b5503460f94a27e4b/html5/thumbnails/7.jpg)
Overview of Stellar Evolution on H-R Diagram
![Page 8: Wavelength flux Spectral energy distributions of bright stars can be used to derive effective temperatures Ay 123 Lecture I - Physical Properties.](https://reader033.fdocuments.net/reader033/viewer/2022042821/56649d4b5503460f94a27e4b/html5/thumbnails/8.jpg)
Evolution During the Main Sequence
Zero Age MS