Located at a site about the proposed
Darwin
mission. In addition to the links related to extrasolar planets,
there are also links related to exobiology, SETI, and similar
topics.
Good site by the team which has found the largest number of
extrasolar planets. Contains a
table of discovered planets, news,
published papers,
external links, and other useful resources. Material for a
more general audience is
here.
An umbrella organization for NASA projects to detect and
study extrasolar planets. "The primary goal of these
interrelated missions is to discover and characterize
planetary systems and Earth-like planets around nearby
stars. The missions are designed to build on each other's
success, each providing an essential step forward toward
the goal of discovering habitable planets and evidence
of life beyond." Missions include
SIM PlanetQuest and
Terrestrial Planet Finder.
The site includes a great deal of background information.
"The Keck Interferometer combines light from the twin Keck
telescopes to measure the emission from dust orbiting nearby
stars and to directly detect and characterizse hot gas giant
planets in other solar systems." Site describes many aspects of
the research program.
Part of NASA's
Planet Quest site.
Kepler "is a special purpose space mission in the NASA
Headquarters Discovery Program for detecting terrestrial planets,
that is, rocky and Earth-size, around other stars." The mission is
scheduled for launch in 2007. The Web site provides information
about the mission, scientific background, a substantial
bibliography of
additional reading, and
external links.
"Kepler, a NASA Discovery mission, is a spaceborne
telescope designed to look for Earth-like planets around
stars beyond our solar system."
Part of NASA's
Planet Quest site.
Official NASA Kepler mission site. Provides a mission overview,
information on the science of
searching for habitable planets, description of the
spacecraft and instrumentation, and news releases.
A NASA research mission "scheduled for launch in 2009, [which]
will determine the positions and distances of stars several hundred
times more accurately than any previous program. This accuracy will
allow SIM to determine the distances to stars throughout the galaxy
and to probe nearby stars for Earth-sized planets."
Part of NASA's
Planet Quest site.
NASA project to develop a space-based telescope especially
for detecting Earth-like extrasolar planets. It is currently
scheduled for launch about 2015.
"The Terrestrial Planet Finder (TPF) will study all aspects of
planets outside our solar system: from their formation and
development in disks of dust and gas around newly forming stars
to the presence and features of those planets orbiting the
nearest stars; from the numbers at various sizes and places
to their suitability as an abode for life."
Part of NASA's
Planet Quest site.
"The COROT space telescope is a mission of astronomy
led by CNES in association with French laboratories (CNRS)
and with several international partners (European countries,
Brazil)." The mission is scheduled to be launched in December,
2006. This site is maintained by
CNES, the French space agency.
Home page of the
European Space Agency's mission
to search for signs of life on extrasolar planets. The mission,
planned for about 2015, will use six telescopes, each at least
1.5 meters in diameter, in orbit at the L2 point. The
"main objective is to detect and characterise Earth-like worlds.
To do this, Darwin will survey 1000 of the closest stars, primarily
looking for small, rocky planets. It will provide images of these
worlds as points of lights." Spectroscopes will be used to detect
and analyze any atmosphere such planets may possess. Darwin will
also be capable of performing other ultra-high-resolution
astronomical research in areas such as star and planet formation,
galactic evolution,
black holes, and the center of the Milky Way.
A site by
Alan Penny about the
European Space Agency mission
planned for
about 2015, which will (among other things) be capable of
searching for signs of life on Earth like planetws orbiting
nearby stars. Includes good
external links.
"MicroFUN is an informal consortium of observers dedicated
to photometric monitoring of interesting microlensing events
in the Galactic Bulge. Our primary scientific objective is to
observe high-magnification microlensing events that give the
best potential for detecting extra-solar planets orbiting the
lensing star."
"The Optical Gravitational Lensing Experiment (OGLE) is a
long term observational program with the main goal to search
for dark, unseen matter using the microlensing phenomena."
Detection of distant extrasolar planets is one possible
product of the experiment.
"The Anglo-Australian Planet Search (AAPS) is a long-term
program being carried out on the 3.9m Anglo-Australian Telescope
(AAT) to search for giant planets around 200 nearby Solar-type stars."
The site includes research news and a brief description of
planet search technique.
PLANET stands for Probing Lensing Anomalies NETwork.
"PLANET uses a network of five 1m-class optical telescopes
distributed in longitude around the southern hemisphere in
order to perform quasi-continuous round-the-clock precision
monitoring of Galactic bulge microlensing events."
Explanation of "microlensing", as used in detection of
extrasolar planets in the
SIM PlanetQuest experiment. Other objects that are otherwise
invisible can be detected with microlensing, such as brown dwarf
stars and concentrations of dark matter. The article is from
the
PlanetQuest site.
June 2007 article about discovery of two planets of the star
HD 155358. The planets are unusual because of their low density
and the low metal content of their parent star.
March 2009 article from
Physics World, by
Alan Boss.
"The abundance of Earth-like planets will be determined in the
next five years, with profound implications for the prevalence
of life in the universe. The author describes the coming
revolution in extrasolar planetology."
June 2004 article from
Physics World, by
Keith Horne. "Astronomers have used gravitational microlensing to
detect a cool planet orbiting a star some 15,000 light-years away."
January 2001 article from
Physics World, by
Andrew Collier Cameron. "Astronomers have detected over 50 giant
planets outside our solar system and made remarkable progress
in determining their properties. But the real prize would be
an Earth-like planet that could harbour life."
February 2007
article from Space.com
about discussions and debates taking place among astronomers
who study extrasolar planets. One of the more significant debates
cocerns the formation and orbital evolution of giant planets.
December 2002
article from Space.com.
Provides an interview with Vikki Meadows, who oversees a computer
simulation project called the Virtual Planetary Laboratory,
which is investigating what observable properties a planet capable
of sustaining some form of life should have.
June 2002
article from Space.com.
Describes new technique for discovering extrasolar planets which
involves detecting fluctuations in light from a star due to
planetary transits.
November 2001
article from Space.com.
Describes how extrasolar planets may be detected by their
variation in brightness as they circle their parent star.
January 2001 article from
Physics World, by
Andrew Collier Cameron.
"Astronomers have detected over 50 giant planets outside our
solar system and made remarkable progress in determining their
properties. But the real prize would be an Earth-like planet
that could harbour life."
December 1999 news article from
PhysicsWeb about an
extrasolar planet believed to have been discovered, by reflected
light, in orbit around tau Bootis.
Science Notes article by Solana Pyne concerning the information
that extrasolar gas giant planets may provide about the process
of planetary formation.
April 1999 Scientific American In Focus article, subtitled
"The discovery of a nearby solar system renders our corner of space
a little bit less lonely."
"Few if any astronomers expected the sheer diversity
of planets beyond our solar system. The most extreme systems
are those that orbit neutron stars, white dwarfs and brown dwarfs."
Search for Other Earths
Tim Appenzeller National Geographic, December 2004, pp. 68-95
Since many Jupiter-size planets have been found orbiting
nearby stars, it is quite likely that Earthlike planets exist
also. The problem is how to detect them.
[Additional resources]
Burning Down to Rock
Charles Choi Scientific American, May 2004
Unlocking New Worlds
Robert Naeye Astronomy, November 2002, pp. 48-53
About 100 extrasolar planets have been identified to date.
There are four different methods of detecting such planets, and
each strains the limits of observational precision in order to
identify solar systems that more closely resemble our own.
Disks of dust and debris around stars are much easier to
observe than planets, but patterns in the disks may still
indicate the existence of planets.
Can We Find Another Earth?
Michael D. Lemonick Discover, March 2002, pp. 32-37
Novel telescope designs based on the principle of interferometry
may make it possible within 20 years to directly detect planets
as small as Earth orbiting other stars.
We Are Not Alone
Oliver Morton Wired, June 2001, pp. 162-169
Finding extrasolar planets has become one of NASA's clearest
long-term goals. The relatively simple and inexpensive Kepler
spacecraft, which would detect extrasolar planets by measuring
minute dips in stellar brightness during planetary transits,
may be the key tool.
Astronomers are now searching for very young stars within
200 light years of Earth which may have planets observable
in infrared.
Discovering Worlds in Transit
Laurance R. Doyle; Hans-Jörg-Deeg; Jon M. Jenkins Astronomy, March 2001, pp. 38-43
All extra-solar planets detected so far have been identified by
means of Doppler shifts caused by wobbles in stellar motion due to
the presence of very massive planets. A different technique is
required to detect Earth-size planets -- observation of very small
dips in stellar brightness that occur when a planet transits in
front of its star.
Searching for Shadows of Other Earths
Laurance R. Doyle; Hans-Jörg Deeg; Timothy M. Brown Scientific American, September 2000, pp. 58-65
Until recently, only giant planets could be detected in
other solar systems. Very sensitive measurements of stellar
brigntness now make it possible to detect Earth-like planets
if they pass in front of their star on their orbit.
Field Guide to New Planets
Kathy A. Svitil Discover, March 2000, pp. 48-55
29 extrasolar planets had been detected
as of the writing of this article. Although such planets must be
very massive to be detected at all, hence quite unlike Earth,
they are quickly adding to our knowledge of planetary systems.
Spying on Planetary Nurseries
Ray Jayawardhana Astronomy, November 1998, pp. 62-67
Within the last year images of dust disks around young stars
have been obtained. Such disks are probably similar to earliest
stage of formation of our own Solar system.
Wanted: Life-Bearing Planets
Doug McInnis Astronomy, April 1998, pp. 38-43
All of the extrasolar planets discovered so far have been
similar in size to Jupiter, much larger than Earth. A variety of
new observational techniques and equipment will search for
Earth-size planets over the next 20 years.
Impossible Planets
Sam Flamsteed Discover, September 1997, pp. 78-83
The extrasolar planets discovered so far have all been very
massive - necessarily so, in order to have been discovered at
all. The solar systems they are part of may be rather different
from ours and have formed in different ways.
The Strange New Planetary Zoo
Robert Naeye Astronomy, April 1997, pp. 42-49
Many of the extrasolar planets discovered so far are
surprising for their size and proximity to their host star.
Some of the objects may even be "brown dwarfs", and planet-like
objects have even been found in orbit around pulsars (neutron
stars).
Extrasolar Planets
Alan P. Boss Physics Today, September 1996, pp. 32-38
Not only have planets similar to those of the Solar System
been discovered associated with other stars, but also more
exotic objects, such as brown dwarf stars and circumstellar
disks.
Searching for Life on Other Planets
J. Roger P. Angel; Neville J. Woolf Scientific American, April 1996, pp. 60-66
Although we are now able to detect planets of other stars,
determining whether they probably harbor life is a much more
difficult problem. A space-based telescope using sensitive
spectroscopic equipment is proposed.
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