Sagittarius Window Eclipsing Extrasolar Planet Search
Encyclopedia
The Sagittarius Window Eclipsing Extrasolar Planet Search, or SWEEPS, was a 2006 astronomical survey project using the Hubble Space Telescope
's Advanced Camera for Surveys - Wide Field Channel to monitor 180,000 stars for seven days to detect extrasolar planet
s via the transit method.
The stars that were monitored in this astronomical survey were all located in the Sagittarius-I Window, a rare transparent
view to the Milky Way
's central bulge stars in the Sagittarius
constellation
as our view to most of the galaxy's central stars is blocked by lanes of dust
. These stars in the galaxy's central bulge region are approximately 27,000 light years from Earth.
s. Planets with orbital periods less than 1.2 days have not previously been detected, and have been dubbed "ultra-short period planets" (USPPs) by the search team. USPPs were discovered only around low-mass stars, suggesting that larger stars destroyed any planets orbiting so closely or that planets were unable to migrate as far inward around larger stars.
Planets were found with roughly the same frequency of occurrence as in the local neighborhood of Earth.
SWEEPS-4 and SWEEPS-11 orbited stars that were sufficiently visually distinct from their neighbors that followup observations using the radial velocity method were possible, allowing their masses to be determined.
This table is constructed from information obtained from the Extrasolar Planets Encyclopedia and SIMBAD
databases that reference the Nature
article as their source.
Hubble Space Telescope
The Hubble Space Telescope is a space telescope that was carried into orbit by a Space Shuttle in 1990 and remains in operation. A 2.4 meter aperture telescope in low Earth orbit, Hubble's four main instruments observe in the near ultraviolet, visible, and near infrared...
's Advanced Camera for Surveys - Wide Field Channel to monitor 180,000 stars for seven days to detect extrasolar planet
Extrasolar planet
An extrasolar planet, or exoplanet, is a planet outside the Solar System. A total of such planets have been identified as of . It is now known that a substantial fraction of stars have planets, including perhaps half of all Sun-like stars...
s via the transit method.
Area examined
Transparency and translucency
In the field of optics, transparency is the physical property of allowing light to pass through a material; translucency only allows light to pass through diffusely. The opposite property is opacity...
view to the Milky Way
Milky Way
The Milky Way is the galaxy that contains the Solar System. This name derives from its appearance as a dim un-resolved "milky" glowing band arching across the night sky...
's central bulge stars in the Sagittarius
Sagittarius (constellation)
Sagittarius is a constellation of the zodiac, the one containing the galactic center. Its name is Latin for the archer, and its symbol is , a stylized arrow. Sagittarius is commonly represented as a centaur drawing a bow...
constellation
Constellation
In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....
as our view to most of the galaxy's central stars is blocked by lanes of dust
Dark nebula
A dark nebula is a type of interstellar cloud that is so dense that it obscures the light from the background emission or reflection nebula or that it blocks out background stars . The extinction of the light is caused by interstellar dust grains located in the coldest, densest parts of larger...
. These stars in the galaxy's central bulge region are approximately 27,000 light years from Earth.
Planets discovered
Sixteen candidate planets were discovered with orbital periods ranging from 0.6 to 4.2 dayDay
A day is a unit of time, commonly defined as an interval equal to 24 hours. It also can mean that portion of the full day during which a location is illuminated by the light of the sun...
s. Planets with orbital periods less than 1.2 days have not previously been detected, and have been dubbed "ultra-short period planets" (USPPs) by the search team. USPPs were discovered only around low-mass stars, suggesting that larger stars destroyed any planets orbiting so closely or that planets were unable to migrate as far inward around larger stars.
Planets were found with roughly the same frequency of occurrence as in the local neighborhood of Earth.
SWEEPS-4 and SWEEPS-11 orbited stars that were sufficiently visually distinct from their neighbors that followup observations using the radial velocity method were possible, allowing their masses to be determined.
This table is constructed from information obtained from the Extrasolar Planets Encyclopedia and SIMBAD
SIMBAD
SIMBAD is an astronomical database of objects beyond the Solar System...
databases that reference the Nature
Nature (journal)
Nature, first published on 4 November 1869, is ranked the world's most cited interdisciplinary scientific journal by the Science Edition of the 2010 Journal Citation Reports...
article as their source.
| Star Star A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth... |
Constellation Constellation In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky.... |
Right ascension Right ascension Right ascension is the astronomical term for one of the two coordinates of a point on the celestial sphere when using the equatorial coordinate system. The other coordinate is the declination.-Explanation:... |
Declination Declination In astronomy, declination is one of the two coordinates of the equatorial coordinate system, the other being either right ascension or hour angle. Declination in astronomy is comparable to geographic latitude, but projected onto the celestial sphere. Declination is measured in degrees north and... |
App. mag. Apparent magnitude The apparent magnitude of a celestial body is a measure of its brightness as seen by an observer on Earth, adjusted to the value it would have in the absence of the atmosphere... |
Distance (ly) | Spectral type Stellar classification In astronomy, stellar classification is a classification of stars based on their spectral characteristics. The spectral class of a star is a designated class of a star describing the ionization of its chromosphere, what atomic excitations are most prominent in the light, giving an objective measure... |
Planet Planet A planet is a celestial body orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and has cleared its neighbouring region of planetesimals.The term planet is ancient, with ties to history, science,... |
Mass Mass Mass can be defined as a quantitive measure of the resistance an object has to change in its velocity.In physics, mass commonly refers to any of the following three properties of matter, which have been shown experimentally to be equivalent:... (MJ Jupiter mass Jupiter mass , is the unit of mass equal to the total mass of the planet Jupiter . Jupiter mass is used to describe masses of the gas giants, such as the outer planets and extrasolar planets. It is also used in describing brown dwarfs.... ) |
Radius Radius In classical geometry, a radius of a circle or sphere is any line segment from its center to its perimeter. By extension, the radius of a circle or sphere is the length of any such segment, which is half the diameter. If the object does not have an obvious center, the term may refer to its... (RJ) |
Orbital period Orbital period The orbital period is the time taken for a given object to make one complete orbit about another object.When mentioned without further qualification in astronomy this refers to the sidereal period of an astronomical object, which is calculated with respect to the stars.There are several kinds of... (d Day A day is a unit of time, commonly defined as an interval equal to 24 hours. It also can mean that portion of the full day during which a location is illuminated by the light of the sun... ) |
Semimajor axis (AU Astronomical unit An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance.... ) |
Orbital eccentricity |
Inclination Inclination Inclination in general is the angle between a reference plane and another plane or axis of direction.-Orbits:The inclination is one of the six orbital parameters describing the shape and orientation of a celestial orbit... (° Degree (angle) A degree , usually denoted by ° , is a measurement of plane angle, representing 1⁄360 of a full rotation; one degree is equivalent to π/180 radians... ) |
Discovery year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| SWEEPS J175853.29-291233.5 | Sagittarius Sagittarius (constellation) Sagittarius is a constellation of the zodiac, the one containing the galactic center. Its name is Latin for the archer, and its symbol is , a stylized arrow. Sagittarius is commonly represented as a centaur drawing a bow... |
22.2 | ~22000 | SWEEPS-01 | ? | 1.01 | 1.56 | 0.025 | ? | 86+ | 2006 | |||
| SWEEPS J175853.38-291217.8 | Sagittarius Sagittarius (constellation) Sagittarius is a constellation of the zodiac, the one containing the galactic center. Its name is Latin for the archer, and its symbol is , a stylized arrow. Sagittarius is commonly represented as a centaur drawing a bow... |
25.1 | ~22000 | SWEEPS-02 | ? | 1.37 | 0.912 | 0.015 | ? | 86+ | 2006 | |||
| SWEEPS J175853.57-291144.1 | Sagittarius Sagittarius (constellation) Sagittarius is a constellation of the zodiac, the one containing the galactic center. Its name is Latin for the archer, and its symbol is , a stylized arrow. Sagittarius is commonly represented as a centaur drawing a bow... |
22.5 | ~22000 | SWEEPS-03 | ? | 0.87 | 1.27 | 0.021 | ? | 86+ | 2006 | |||
| SWEEPS J175853.92−291120.6 | Sagittarius Sagittarius (constellation) Sagittarius is a constellation of the zodiac, the one containing the galactic center. Its name is Latin for the archer, and its symbol is , a stylized arrow. Sagittarius is commonly represented as a centaur drawing a bow... |
18.8 | ~22000 | SWEEPS-04 | <3.8 | 0.81 | 4.2 | 0.055 | ? | 87+ | 2006 | |||
| SWEEPS J175854.60-291128.2 | Sagittarius Sagittarius (constellation) Sagittarius is a constellation of the zodiac, the one containing the galactic center. Its name is Latin for the archer, and its symbol is , a stylized arrow. Sagittarius is commonly represented as a centaur drawing a bow... |
23.9 | ~22000 | SWEEPS-05 | ? | 1.09 | 2.313 | 0.030 | ? | 87+ | 2006 | |||
| SWEEPS J175857.29-291253.4 | Sagittarius Sagittarius (constellation) Sagittarius is a constellation of the zodiac, the one containing the galactic center. Its name is Latin for the archer, and its symbol is , a stylized arrow. Sagittarius is commonly represented as a centaur drawing a bow... |
19.5 | ~22000 | SWEEPS-06 | ? | 0.82 | 3.039 | 0.042 | ? | 86+ | 2006 | |||
| SWEEPS J175857.69-291114.5 | Sagittarius Sagittarius (constellation) Sagittarius is a constellation of the zodiac, the one containing the galactic center. Its name is Latin for the archer, and its symbol is , a stylized arrow. Sagittarius is commonly represented as a centaur drawing a bow... |
21.5 | ~22000 | SWEEPS-07 | ? | 0.9 | 1.747 | 0.027 | ? | 86+ | 2006 | |||
| SWEEPS J175859.24-291328.7 | Sagittarius Sagittarius (constellation) Sagittarius is a constellation of the zodiac, the one containing the galactic center. Its name is Latin for the archer, and its symbol is , a stylized arrow. Sagittarius is commonly represented as a centaur drawing a bow... |
21.7 | ~22000 | SWEEPS-08 | ? | 0.98 | 0.868 | 0.017 | ? | 84+ | 2006 | |||
| SWEEPS J175859.60-291211.8 | Sagittarius Sagittarius (constellation) Sagittarius is a constellation of the zodiac, the one containing the galactic center. Its name is Latin for the archer, and its symbol is , a stylized arrow. Sagittarius is commonly represented as a centaur drawing a bow... |
22.5 | ~22000 | SWEEPS-09 | ? | 1.01 | 1.617 | 0.025 | ? | 86+ | 2006 | |||
| SWEEPS J175902.00-291323.7 SWEEPS-10 |- style="vertical-align: top;"SWEEPS-10 is, as of June 2007, the planet candidate with the shortest orbital period yet found. The planet orbits the star SWEEPS J175902.00−291323.7 located in the Galactic bulge at a distance of approximately 22000 light years from Earth... |
Sagittarius Sagittarius (constellation) Sagittarius is a constellation of the zodiac, the one containing the galactic center. Its name is Latin for the archer, and its symbol is , a stylized arrow. Sagittarius is commonly represented as a centaur drawing a bow... |
26.2 | ~22000 | SWEEPS-10 SWEEPS-10 |- style="vertical-align: top;"SWEEPS-10 is, as of June 2007, the planet candidate with the shortest orbital period yet found. The planet orbits the star SWEEPS J175902.00−291323.7 located in the Galactic bulge at a distance of approximately 22000 light years from Earth... |
? | 1.24 | 0.424 | 0.008 | ? | 84+ | 2006 | |||
| SWEEPS J175902.67−291153.5 SWEEPS-11 SWEEPS-11 is an extrasolar planet orbiting the star SWEEPS J175902.67−291153.5 in the constellation Sagittarius approximately 22000 light years away from the Solar System... |
Sagittarius Sagittarius (constellation) Sagittarius is a constellation of the zodiac, the one containing the galactic center. Its name is Latin for the archer, and its symbol is , a stylized arrow. Sagittarius is commonly represented as a centaur drawing a bow... |
19.83 | ~22000 | SWEEPS-11 SWEEPS-11 SWEEPS-11 is an extrasolar planet orbiting the star SWEEPS J175902.67−291153.5 in the constellation Sagittarius approximately 22000 light years away from the Solar System... |
9.7 | 1.13 | 1.796 | 0.03 | ? | 84+ | 2006 | |||
| SWEEPS J175904.44-291317.1 | Sagittarius Sagittarius (constellation) Sagittarius is a constellation of the zodiac, the one containing the galactic center. Its name is Latin for the archer, and its symbol is , a stylized arrow. Sagittarius is commonly represented as a centaur drawing a bow... |
21.8 | ~22000 | SWEEPS-12 | ? | 0.91 | 2.952 | 0.038 | ? | 87+ | 2006 | |||
| SWEEPS J175905.95-291305.6 | Sagittarius Sagittarius (constellation) Sagittarius is a constellation of the zodiac, the one containing the galactic center. Its name is Latin for the archer, and its symbol is , a stylized arrow. Sagittarius is commonly represented as a centaur drawing a bow... |
21.38 | ~22000 | SWEEPS-13 | ? | 0.78 | 1.684 | 0.027 | ? | 86+ | 2006 | |||
| SWEEPS J175907.56-291039.8 | Sagittarius Sagittarius (constellation) Sagittarius is a constellation of the zodiac, the one containing the galactic center. Its name is Latin for the archer, and its symbol is , a stylized arrow. Sagittarius is commonly represented as a centaur drawing a bow... |
22.38 | ~22000 | SWEEPS-14 | ? | 0.93 | 2.965 | 0.037 | ? | 87+ | 2006 | |||
| SWEEPS J175907.64-291023.7 | Sagittarius Sagittarius (constellation) Sagittarius is a constellation of the zodiac, the one containing the galactic center. Its name is Latin for the archer, and its symbol is , a stylized arrow. Sagittarius is commonly represented as a centaur drawing a bow... |
25.66 | ~22000 | SWEEPS-15 | ? | 1.37 | 0.541 | 0.010 | ? | 84+ | 2006 | |||
| SWEEPS J175908.44-291140.6 | Sagittarius Sagittarius (constellation) Sagittarius is a constellation of the zodiac, the one containing the galactic center. Its name is Latin for the archer, and its symbol is , a stylized arrow. Sagittarius is commonly represented as a centaur drawing a bow... |
23.78 | ~22000 | SWEEPS-16 | ? | 1.4 | 0.969 | 0.017 | ? | 85+ | 2006 |
See also
- Optical Gravitational Lensing ExperimentOptical Gravitational Lensing ExperimentThe Optical Gravitational Lensing Experiment or OGLE is a Polish astronomical project based at the University of Warsaw that is chiefly concerned with discovering dark matter using the microlensing technique. Since the project began in 1992, it has discovered several extrasolar planets as a side...
or OGLE also examines the galactic bulge for planets. - Baade's WindowBaade's WindowBaade's Window is an area of the sky with relatively low amounts of interstellar "dust" along the line of sight from the Earth. This area is considered an observational "window" as the normally obscured Galactic Center of the Milky Way is visible in this direction. It is named for astronomer Walter...