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I work on theoretical and observational projects related to
directly imaging Extrasolar Planetary Systems.
This page describes some of my research interests
and provides links to other pages useful to my collaborators.
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Some White Dwarfs appear to host clouds of dust
similar to cometary dust in the solar system. Our sun will eventually
become a white dwarf; dusty white dwarfs may represent the future of
planetary systems like the solar system. Directly imaging planets
around white dwarfs may be especially easy, because a white dwarf is
smaller than Jupiter!
Powerpoint Press Release Talk on
Cometary Dust around a White Dwarf
Powerpoint Talk on WDs I gave at
Carnegie DTM 2/06
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The technique of Coronagraphy increases the dynamic range of a telescope so
it can see planets without being swamped by the glare from the stars they orbit.
Here is an image of Sirius made with a conventional coronagraph.
I am working on a new design concept for a
Terrestrial Planet Finder
telescope in space: a Coronagraph with a Band-Limited Mask..
The latest version of the band-limited mask is the
eighth-order mask.
Another potential way to directly image extrasolar planets is with
a groundbased Giant Segmented Mirror Telescope.
We may also someday see radio synchrotron emission from extrasolar
planets.
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Imagining New Kinds of Planets can help us decide where and how to look for
extrasolar planets.
Extrasolar planets are not necessarily like the ones in the solar system; they may
have completely different chemistries, like
Water Planets or
Carbon Planets .
Life on a carbon planet would be through-the-looking-glass. The processes of burning and
metabolism on Earth are oxidation (combining things with oxygen); on a carbon planet,
these processes would probably be replaced by reduction (combining things with carbon).
Artist Lynette Cook created this image of a Carbon Planet.
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General Astrophysics with TPF
What can the Terrestrial Planet Finder missions do besides look for extrasolar Earths?
They can study Jupiters, Neptunes, and debris disks.
And with an extra instrument or two, they can potentially search
for high-z supernovae, map protoplanetary disks in molecular
hydrogen, and image AGNs, AGBs and distant galaxies at a
resolution of 1 milliarcsecond.
General Astrophysics with TPF Workshop
General Astrophysics and Comparative Planetology White Paper
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Our Sun sports a handsome disk of zodiacal dust, full of structures
due to the dynamical effects of planets. Here is an explanation, with illustrations,
of how planets on low-eccentricity orbits make rings and wakes in an optically thin
circumstellar dust cloud. Zodiacal dust around other stars is called Exozodiacal Dust.
This animation shows what a few-jupiter-mass planet
on an eccentric orbit (e=0.6) can do to a dust cloud.
The solar system doesn't have any such planets, but extrasolar planetary systems often do.
Millimeter maps of the debris around Vega show two blobs of
emission at different distances from the star which may be the same phenomenon.
However, this disk and other Debris Disks may be much more complicated than
the solar dust cloud.
Animation of Dust Orbiting Vega
Press Release on Millimeter Maps of Vega
Powerpoint Talk on Resonant Signatures in Debris Disks
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Finding faint objects such as planets and dust disks near bright,
nearby stars takes high resolution and high dynamic range. Optical
and infrared Interferometry
can provide high resolution and high dynamic range by combining the light from
two or more widely-spaced telescopes. Interferometers like the
Palomar Testbed
Interferometer are already capable of resolutions of almost 1 milliarcsecond,
enough to resolve an object the size of a nickel in New York---from a mountaintop
in California.
The Keck
Interferometer will have almost as high resolution as
PTI, and it will harness the collecting area of the two 10-meter Keck telescopes.
This new tool can probe the central 1 AU of debris disks, and
disks around Young Stellar Objects.
Powerpoint Talk on Keck Interferometer Nuller Shared Risk Science Program
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Here is the ZODIPIC package, an IDL program
for synthesizing images of exozodiacal clouds.
It also has enough tweakable parameters to serve as a
general-purpose modeling tool for optically-thin disks. To use it, you may
download zodipic
to your idl directory. Save the file as "zodipic.2.1.tar". Then
type
tar xvf zodipic.2.1.tar
to unpack the files (total about 57K). The README.zodipic file describes how to run the code.
The picture above was made by running zodipic twice:
zodipic, fnu1, 1, 0.5, inclination=60, positionangle=-10, ring=1, blob=1, pixnum=256, /noiterate, /nofan
zodipic, fnu2, 1, 0.5, inclination=60, positionangle=-10, ring=1, blob=1, pixnum=256, /noiterate, /nofan, radring=0.72, earthlong=100
NEW! Zodipic Version 2.1.
Includes dust with real optical constants, user-specified dust maps, and more!
See also
Kuchner, M. J., & Serabyn, E. 2001, submitted to ApJ
Powerpoint Talk on ZODIPIC
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On some cloudy nights, I like to write
Observing Manuals like this
guide to the Palomar 60" CCD Camera.
And here are some of my other Powerpoint Talks
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I am lucky to work with some talented
Graduate Students and Postdocs:
Chris Stark Graduate Student, U. Maryland Physics Dept.
Daniel
Jontof-Hutter Grad. Student, U.M.D. Astronomy
Justin Crepp Graduate
Student, U. Florida, Astronomy Dept.
Aki Roberge NPP Postdoctoral Fellow, GSFC
Ruslan Belikov NPP Postdoctoral Fellow, GSFC
Hannah
Jang-Condell Michelson Post. Fellow,
GSFC
John Wisniewski NPP Postdoctoral Fellow, GSFC
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If you are in the DC area, please stop by and give a talk at the Goddard
Exoplanets Club. We meet on Thursdays at noon at Goddard
in Building 21, Room 183.
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Here are some possibly useful
Astronomy Links:
Q&A
With Astronomy Magazine
Princeton Astronomy Webmail
Aspen Conference on Planet Formation and
Detection February 6-12, 2005
JPL Docushare
Princeton Seminar Series on Extrasolar Planets and Astrobiology
Paw Points
Database of Observational Mishaps
Statistical Consulting Center for Astronomy
Cosmic Dust
Caltech Ge 167
CfA Star and Planet Formation Journal Club
Astronomy Meetings
CDS 270
Ephemerides
SOFIA
Exploring Neighboring Planetary Systems
Harvard Extrasolar Planets Site
California/Carnegie Extrasolar Planets Site
Astrophysics Data System
Caltech Astronomy Department
Astronomical Pronunciation Guide
Simbad astronomical database
Skyview virtual telescope
RECONS Research Consortium on Nearby Stars
NStars
astro-ph Preprint Server
Division of Dynamical Astronomy
ExNPS Exploring Neighboring Planetary Systems site at JPL
Protostars and Planets IV
Astrobiology Office at NASA Ames Research Center.
NED NASA/IPAC Extragalactic Database.
The Large Binocular Telescope
The Submillimeter Array
Atacama Large Millimeter Array
Harvard College Observatory Tennis Club
Did you know that Queen guitarist Brian May used to
study zodiacal dust?
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