OGLE-2003-BLG-235L
Encyclopedia
OGLE-2003-BLG-235/MOA 2003-BLG-53 was a gravitational microlensing
event which occurred in the constellation
of Sagittarius
during July 2003. The event was observed both as part of the Optical Gravitational Lensing Experiment
(OGLE) and by the Microlensing Observations in Astrophysics
group (MOA), hence the double designation. The source star in the gravitational lens is a main sequence
star of spectral type
G located around 8.8 kiloparsecs (29,000 light years) away in the galactic bulge. The lens star is an orange dwarf
star of spectral type K, which is accompanied by a giant planet.
mass range). The star was originally assumed to be a red dwarf
star, since they are the most common type of star in the galaxy.
By 2006, the source and lens star had moved far enough apart (as viewed from Earth) that their light could be separated. Observations by the Hubble Space Telescope
revealed that in fact the lens star was actually brighter and less red than expected, matching the expected spectra for a K dwarf of about 0.63 solar mass
es, more massive than the average star in the galaxy. This enables an estimate of the distance to the lens star, which puts it at around 5.8 kiloparsecs (19,000 light years) away.
Gravitational microlensing
Gravitational microlensing is an astronomical phenomenon due to the gravitational lens effect. It can be used to detect objects ranging from the mass of a planet to the mass of a star, regardless of the light they emit. Typically, astronomers can only detect bright objects that emit lots of light ...
event which occurred in the 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....
of 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...
during July 2003. The event was observed both as part of the Optical Gravitational Lensing Experiment
Optical Gravitational Lensing Experiment
The 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...
(OGLE) and by the Microlensing Observations in Astrophysics
Microlensing Observations in Astrophysics
Microlensing Observations in Astrophysics is a collaborative project between researchers in New Zealand and Japan, led by Professor Yasushi Muraki of Nagoya University. They use microlensing to observe dark matter, extra-solar planets, and stellar atmospheres from the Southern Hemisphere...
group (MOA), hence the double designation. The source star in the gravitational lens is a main sequence
Main sequence
The main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Hertzsprung and Henry Norris Russell...
star of 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...
G located around 8.8 kiloparsecs (29,000 light years) away in the galactic bulge. The lens star is an orange dwarf
Orange dwarf
A K-type main-sequence star , also referred to orange dwarf, are main-sequence stars of spectral type K and luminosity class V. These stars are intermediate in size between red M-type main-sequence stars and yellow G-type main-sequence stars...
star of spectral type K, which is accompanied by a giant planet.
Lens system
OGLE-2003-BLG-235L/MOA-2003-BLG-53L is the designation given to the star in the lens system. In 2004, analysis of the light curve produced as it passed in front of the source star allowed detection of an exoplanet orbiting the star with a mass 0.0039 times that of the host star (this would put it in the jovianJupiter
Jupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with mass one-thousandth that of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn,...
mass range). The star was originally assumed to be a red dwarf
Red dwarf
According to the Hertzsprung-Russell diagram, a red dwarf star is a small and relatively cool star, of the main sequence, either late K or M spectral type....
star, since they are the most common type of star in the galaxy.
By 2006, the source and lens star had moved far enough apart (as viewed from Earth) that their light could be separated. Observations by the Hubble Space Telescope
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...
revealed that in fact the lens star was actually brighter and less red than expected, matching the expected spectra for a K dwarf of about 0.63 solar mass
Solar mass
The solar mass , , is a standard unit of mass in astronomy, used to indicate the masses of other stars and galaxies...
es, more massive than the average star in the galaxy. This enables an estimate of the distance to the lens star, which puts it at around 5.8 kiloparsecs (19,000 light years) away.
Planetary system
The OGLE-2003-BLG-235L/MOA-2003-BLG-53L system consists of one planet as determined by the discovery team and the followup confirmation observations.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 - List of extrasolar planets