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Associated Faculty and
Web Pages listed below.
Solar and Stellar Magnetic Activity.
Magnetic fields play an important role
in astrophysics, but the generation of these fields and the means by which
they accelerate and heat plasmas are poorly understood. In the Sun and
similar stars magnetic fields produce sunspots or starspots, activity cycles,
optical and ultraviolet emission lines, stellar winds, coronal X-ray emission,
and flares. These phenomena are being studied in the Sun and nearby stars
using optical ground-based observations, as well as space data from the
rocket-borne telescopes, and from satellites such as
ROSAT,
TRACE,
Solar and Heliospheric Observatory (SoHO)
and others. The plasma heating and acceleration of the solar wind is
studied through far ultraviolet coronal spectrometers developed by CfA
for the NASA mission SoHO. Physical conditions in the outer atmospheres of the
Sun and stars are modeled using sophisticated radiative transfer programs.
Stellar Imaging.
A new era in stellar physics is made possible by techniques
which allow us to resolve the surfaces of stars other than the Sun.
Interferometric techniques are used with CfA's telescope array
IOTA to
obtain the angular diameters of nearby stars and pulsating supergiant stars.
Direct imaging has been achieved with the
Hubble Space Telescope in the
ultraviolet. New methods for stellar imaging at very large distances with
the help of gravitational microlensing are being developed.
Solar and Stellar Seismology.
High precision radial velocity observations of
the Sun have revealed a rich spectrum of pulsations, which give valuable
information on its interior structure and dynamics. Programs are underway
using solar observations and theory to exploit this field of "helioseismology".
Also underway are efforts to detect similar small amplitude pulsations in
nearby stars, and thus provide an important check on stellar structure theory.
Associated Professors and Lecturers
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D. Charbonneau,
G. Rybicki,
D. Sasselov,
Associated Web Pages
- TRACE
- AFOE:
A Spectrograph for Precise Stellar Radial Velocity
Measurements
- ASCE:Advanced Solar Coronal
Explorer
- Spartan
Ultraviolet Coronal Spectrometer
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SOHO UltraViolet Coronagraph Spectrometer
- MOST
--Microvariability and Oscillations of Stars Microsatellite Mission
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Stellar microscopy, microlensing to image distant stars
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IOTA: Infrared Optical Telescope Array
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SMA:
The Smithsonian Submillimeter Wavelength Array
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Mid-Infrared Array Camera, MIRAC
- SIRTF, Space
Infrared Telescope Facility and
IRAC, its Infrared Camera
Associated Divisions
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Radio and Geoastronomy,
Solar and Stellar, and Planetary Sciences ,
Theoretical Astrophysics,
High Energy Astrophysics
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