Related Research Articles
In astronomy, the main sequence is a classification of stars which appear on plots of stellar color versus brightness as a continuous and distinctive band. Stars on this band are known as main-sequence stars or dwarf stars, and positions of stars on and off the band are believed to indicate their physical properties, as well as their progress through several types of star life-cycles. These are the most numerous true stars in the universe and include the Sun. Color-magnitude plots are known as Hertzsprung–Russell diagrams after Ejnar Hertzsprung and Henry Norris Russell.
A red dwarf is the smallest kind of star on the main sequence. Red dwarfs are by far the most common type of fusing star in the Milky Way, at least in the neighborhood of the Sun. However, due to their low luminosity, individual red dwarfs cannot be easily observed. From Earth, not one star that fits the stricter definitions of a red dwarf is visible to the naked eye. Proxima Centauri, the star nearest to the Sun, is a red dwarf, as are fifty of the sixty nearest stars. According to some estimates, red dwarfs make up three-quarters of the fusing stars in the Milky Way.
The solar mass (M☉) is a standard unit of mass in astronomy, equal to approximately 2×1030 kg (20 nonillion kilograms in US short scale). It is approximately equal to the mass of the Sun. It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxies and black holes. More precisely, the mass of the Sun is
The red-giant branch (RGB), sometimes called the first giant branch, is the portion of the giant branch before helium ignition occurs in the course of stellar evolution. It is a stage that follows the main sequence for low- to intermediate-mass stars. Red-giant-branch stars have an inert helium core surrounded by a shell of hydrogen fusing via the CNO cycle. They are K- and M-class stars much larger and more luminous than main-sequence stars of the same temperature.
OGLE-TR-122 is a binary stellar system containing one of the smallest main-sequence stars whose radius has been measured. It was discovered when the Optical Gravitational Lensing Experiment (OGLE) survey observed the smaller star eclipsing the larger primary. The orbital period is approximately 7.3 days. The system's primary is thought to resemble the Sun.
OGLE-TR-111 is a yellow dwarf star approximately 5,000 light-years away in the constellation of Carina. Having an apparent magnitude of about 17, this distant and dim star has not yet been cataloged. Because its apparent brightness changes when one of its planets transits, the star has been given the variable star designation V759 Carinae.
OGLE-TR-10 is a distant, magnitude 16 star in the constellation of Sagittarius. It is located near the Galactic Center. This star is listed as an eclipsing type variable star with the eclipse due to the passage of the planet as noted in the discovery papers.
OGLE-TR-132 is a distant magnitude 15.72 star in the star fields of the constellation Carina. Because of its great distance, about 4,900 light-years, and location in the crowded field it was not notable in any way. Because its apparent brightness changes when one of its planets transits, the star has been given the variable star designation V742 Carinae. The spectral type of the star is type F. A yellow-white, very metal-rich dwarf star, it is slightly hotter and more luminous than the Sun.
OGLE-TR-10b is an extrasolar planet orbiting the star OGLE-TR-10.
OGLE-2005-BLG-390Lb is a super-Earth ice exoplanet orbiting OGLE-2005-BLG-390L, a star 21,500 ± 3,300 light-years from Earth near the center of the Milky Way, making it one of the most distant planets known. On January 25, 2006, Probing Lensing Anomalies NETwork/Robotic Telescope Network (PLANET/Robonet), Optical Gravitational Lensing Experiment (OGLE), and Microlensing Observations in Astrophysics (MOA) made a joint announcement of the discovery. The planet does not appear to meet conditions presumed necessary to support life.
The Optical Gravitational Lensing Experiment (OGLE) is a Polish astronomical project based at the University of Warsaw that runs a long-term variability sky survey (1992–present). The main goals are the detection and classification of variable stars, discovery of microlensing events, dwarf novae, and studies of the structure of the Galaxy and the Magellanic Clouds. Since the project began in 1992, it has discovered a multitude of extrasolar planets, together with the first planet discovered using the transit method (OGLE-TR-56b) and gravitational microlensing. The project has been led by professor Andrzej Udalski since its inception.
OGLE-TR-56 is a dim, distant, magnitude 17 Sun-like star located approximately 1,500 parsecs away in the constellation of Sagittarius. This star is listed as an eclipsing type variable star with the eclipse due to the passage of the planet as noted in the discovery papers.
OGLE-TR-113 is a dim, distant magnitude 16 binary star in the star fields of the constellation Carina. Because of its distance of about 1170 light years, and location in a crowded field it was not notable in any way. Its apparent brightness changes when one of its planets transits, so the star has been given the variable star designation V752 Carinae. Spectral type of the star is type K dwarf star, slightly cooler and less luminous than the Sun.
OGLE-TR-211b is a transiting planet in Carina constellation. Its radius is about 36% more than Jupiter and has mass 3% more than Jupiter, which is considered an “inflated Hot Jupiter”. The planet takes 3.7 days at about the same distance as 51 Pegasi b orbits around 51 Pegasi.
OGLE-TR-113b is an extrasolar planet orbiting the star OGLE-TR-113.
OGLE-TR-111b is an extrasolar planet approximately 5,000 light-years away in the constellation of Carina. The planet is currently the only confirmed planet orbiting the star OGLE-TR-111.
OGLE-TR-132b is an extrasolar planet orbiting the star OGLE-TR-132.
2MASS J0523−1403 is a very-low-mass red dwarf about 40 light-years from Earth in the southern constellation of Lepus, with a very faint visual magnitude of 21.05 and a low effective temperature of 2074 K. It is visible primarily in large telescopes sensitive to infrared light. 2MASS J0523−1403 was first observed as part of the Two Micron All-Sky Survey (2MASS).
OGLE-2007-BLG-349(AB)b is a circumbinary extrasolar planet about 8,000 light-years away in the constellation of Sagittarius. It is the first circumbinary exoplanet to be discovered using the microlensing method of detecting exoplanets.
EBLM J0555-57 is a triple star system approximately 670 light-years from Earth. The system's discovery was released on July 12, 2017. EBLM J0555-57Ab, the smallest star in the system, orbits its primary star with a period of 7.8 days, and currently is the smallest known star with a mass sufficient to enable the fusion of hydrogen in its core.
References
- 1 2 3 The Optical Gravitational Lensing Experiment. Additional Planetary and Low-Luminosity Object Transits from the OGLE 2001 and 2002 Observational Campaigns, A. Udalski, G. Pietrzynski, M. Szymanski, M. Kubiak, K. Zebrun, I. Soszynski, O. Szewczyk, and L. Wyrzykowski, Acta Astronomica53 (June 2003), pp. 133–149.
- 1 2 3 4 5 6 7 8 Radius and mass of a transiting M dwarf near the hydrogen-burning limit. OGLE-TR-123, F. Pont, C. Moutou, F. Bouchy, R. Behrend, M. Mayor, S. Udry, D. Queloz, N. Santos, and C. Melo, Astronomy and Astrophysics447, #3 (March 1, 2006), pp. 1035–1039. doi:10.1051/0004-6361:20053692. Bibcode:2006A&A...447.1035P.
- ↑ Theory of Low-Mass Stars and Substellar Objects, Gilles Chabrier and Isabelle Baraffe, Annual Review of Astronomy and Astrophysics38 (2000), pp. 337–377.
| Stars |
| ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| |||||||||||
| Star clusters |
| ||||||||||
| Nebulae |
| ||||||||||
| Galaxies |
| ||||||||||
| |||||||||||
| |||||||||||
 | This binary or multiple star system–related article is a stub. You can help Wikipedia by expanding it. |