Using Hubble to Measure the
Distances to Stars
Gail Schaefer
Space Telescope Science Institute
Luminosity and the
Inverse Square Law
Luminosity
Apparent Brightness=
2
4 Distance
Luminosity and the
Inverse Square Law
Luminosity
Apparent Brightness=
2
4 Distance
Luminosity and the
Inverse Square Law
Luminosity
Apparent Brightness=
2
4 Distance
Luminosity and the
Inverse Square Law
Luminosity
Apparent Brightness=
2
4 Distance
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Parallax
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1 AU
Parallax =
Distance
p
d
1 AU
Stellar Spectra
Spectral Type
Temperature (K)
O
>28,000
B
10,000 - 28,000
A
7500 - 10,000
F
6000 - 7500
G
5000 - 6000
K
3500 - 5000
M
<3500
Image Credit: ESA Educational Support
Hertzsprung-Russell Diagram
Hipparcos Satellite (ESA)
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Launched in 1989
Measured positions
of 120,000 stars
Measured distances
to of 21,000 stars out
to 300 light-years
(10%)
Hertzsprung-Russell Diagram
Figure credit:
Richard Powell
based on data
Hipparcos Catalog
and Gliese Catalog
Star Clusters
Stars in clusters
are located at the
same distance
and have the
same age.
Image Credit: M. Bolte (University of California, Santa Cruz)
Hyades Cluster
Luminosity
Distance = 150 light-years
Temperature
Image Credit: Sobolev Astronomical Institute,
St. Petersburg
Figure Credit: Perryman et al. 1998
Pleiades - Main Sequence Fitting
Distance = 440 light-years
Image Credit: NASA, ESA, AURA, Caltech
Figure Credit: Bennet, Donohue,
Schneider, “The Cosmic Perspective”
Red Clump Stars
Figure Credit: Stanek & Garnavich
based on Hipparcos data
Cepheid Variables
Credit: NASA, HST,W. Freedman (CIW), R. Kennicutt (U. Arizona), J. Mould (ANU)
Cepheid Variables
Credit: NASA, HST,W. Freedman (CIW), R. Kennicutt (U. Arizona), J. Mould (ANU)
Cepheid Variables
Credit: ESA Educational Support
Cepheid: Period Luminosity
Relation
Figure Credit: Bennett, Donohue, Schneider, “The Cosmic Perspective”
Type Ia Supernova
SN 1994D
NGC 4526
Distance:
52 Million Light-years
Image Credit: High-Z Supernova Search Team, HST, NASA
Type Ia Supernova
Figure Credit: Paul Ricker
Type Ia Supernova
Light Curve
Figure Credit: Richmond et al. 1995
Rotation of Spiral Galaxies
Figure Credit: Nick Strobel's Astronomy Notes
Galaxy Luminosity
Tully-Fisher Relation
Rotation Velocity
Credit: ESA, NASA
Credit: The Internet Encyclopedia of Science
Extragalactic Distance Scale
Figure Credit: Bennett, Donohue, Schneider, “The Cosmic Perspective”
Hubble's Law
Hubble Constant:
H0 = 72 km/s/Mpc
Age of Universe:
13.7 billion years
Figure Credit: Imamura (University of Oregon)
Cosmic Distance Ladder
Supernovae
Tully-Fisher
Cepheids
Red Clump
Main Sequence
Parallax
Cosmic Distance Ladder
Supernovae
Tully-Fisher
Cepheids
Red Clump
Main Sequence
Parallax
Cosmic Distance Ladder
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Cosmic Distance Ladder
Supernovae
Tully-Fisher
Cepheids
Red Clump
Main Sequence
Parallax
Hubble Space Telescope and
the Fine Guidance Sensors
The Fine Guidance Sensors
The Fine Guidance Sensors
The Fine Guidance Sensors
FGS Scan of a Star
Transfer Mode
Position Mode
Credit: STScI
FGS Scan of a Star
Single Star
Binary Star
Credit: STScI
FGS Scan of a Star
Transfer Mode
Position Mode
Credit: STScI
FGS Parallax Observations
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FGS Parallax Observations
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FGS Distance to the Pleiades
Distance = 440 light-years
Image Credit: NASA, ESA, AURA, Caltech
Soderblom et al. 2005
Cepheids and the
Large Magellanic Cloud
Image Credit: Chris Smith (CTIO)
FGS Distances to Cepheids
Period-Luminosity Relation
from Benedict et al. 2007
4 more Cepheid distances
are being measured by
Howard Bond & collaborators
at STScI
Future Space Missions
Gaia - ESA
Space Interferometry Mission
NASA