Atmospheric refraction is the deviation of light or other electromagnetic wave from a straight line as it passes through the atmosphere due to the variation in air density as a function of height. This refraction is due to the velocity of light through air, decreasing with increased density. Atmospheric refraction near the ground produces mirages. Such refraction can also raise or lower, or stretch or shorten, the images of distant objects without involving mirages. Turbulent air can make distant objects appear to twinkle or shimmer. The term also applies to the refraction of sound. Atmospheric refraction is considered in measuring the position of both celestial and terrestrial objects.
Gravitational microlensing is an astronomical phenomenon due to the gravitational lens effect. It can be used to detect objects that range 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 much light (stars) or large objects that block background light. These objects make up only a minor portion of the mass of a galaxy. Microlensing allows the study of objects that emit little or no light.
The Calar Alto Observatory is an astronomical observatory located in Almería province in Spain on Calar Alto, a 2,168-meter-high (7,113 ft) mountain in the Sierra de Los Filabres range.
OGLE-2005-BLG-390Lb is a super-Earth exoplanet orbiting OGLE-2005-BLG-390L, a star 21,500 ± 3,300 light years from Earth near the center of the Milky Way. It is one of the most distant planets known. On 25 January 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.
A telescope is an optical instrument using lenses, curved mirrors, or a combination of both to observe distant objects, or various devices used to observe distant objects by their emission, absorption, or reflection of electromagnetic radiation. The first known practical telescopes were refracting telescopes invented in the Netherlands at the beginning of the 17th century, by using glass lenses. They were used for both terrestrial applications and astronomy.
The Transiting Exoplanet Survey Satellite (TESS) is a space telescope for NASA's Explorers program, designed to search for exoplanets using the transit method in an area 400 times larger than that covered by the Kepler mission. It was launched on April 18, 2018, atop a Falcon 9 rocket and was placed into a highly elliptical 13.7-day orbit around the Earth. The first light image from TESS was taken on August 7, 2018, and released publicly on September 17, 2018.
PLAnetary Transits and Oscillations of stars (PLATO) is a space telescope under development by the European Space Agency for launch in 2026. The mission goals are to search for planetary transits across up to one million stars, and to discover and characterize rocky extrasolar planets around yellow dwarf stars, subgiant stars, and red dwarf stars. The emphasis of the mission is on earth-like planets in the habitable zone around sun-like stars where water can exist in liquid state. It is the third medium-class mission in ESA's Cosmic Vision programme and named after the influential Greek philosopher Plato, the founding figure of Western philosophy, science and mathematics. A secondary objective of the mission is to study stellar oscillations or seismic activity in stars to measure stellar masses and evolution and enabling the precise characterization of the planet host star, including its age.
The Gemini Planet Imager (GPI) is a high contrast imaging instrument that was built for the Gemini South Telescope in Chile. The instrument achieves high contrast at small angular separations, allowing for the direct imaging and integral field spectroscopy of extrasolar planets around nearby stars. The collaboration involved in planning and building the Gemini Planet imager includes the American Museum of Natural History (AMNH), Dunlap Institute, Gemini Observatory, Herzberg Institute of Astrophysics (HIA), Jet Propulsion Laboratory, Lawrence Livermore National Lab (LLNL), Lowell Observatory, SETI Institute, The Space Telescope Science Institute (STSCI), the University of Montreal, University of California, Berkeley, University of California, Los Angeles (UCLA), University of California, Santa Cruz (UCSC), University of Georgia.
An exoplanet is a planet located outside the Solar System. The first evidence of an exoplanet was noted as early as 1917, but was not recognized as such until 2016. No planet discovery has yet come from that evidence. However, the first scientific detection of an exoplanet began in 1988. Afterwards, the first confirmed detection came in 1992, with the discovery of several terrestrial-mass planets orbiting the pulsar PSR B1257+12. The first confirmation of an exoplanet orbiting a main-sequence star was made in 1995, when a giant planet was found in a four-day orbit around the nearby star 51 Pegasi. Some exoplanets have been imaged directly by telescopes, but the vast majority have been detected through indirect methods, such as the transit method and the radial-velocity method. As of 1 February 2021, there are 4,414 confirmed exoplanets in 3,257 systems, with 722 systems having more than one planet. This is a list of the most notable discoveries.
A potentially habitable exoplanet is a hypothetical type of planet that has liquid water and may support life. As of March 2020, a total of 55 potentially habitable exoplanets have been found. Of those, one is believed to be Sub-terran (Mars-size), 20 Terran (Earth-size) and 34 Super Terran. The most potentially habitable exoplanet discovered so far is Teegarden b, with an Earth Similarity Index of 0.93. The main feature of potentially habitable exoplanets is that they have to be located in the habitable zone of their stellar systems.
Kepler-186f (also known by its Kepler object of interest designation KOI-571.05) is an exoplanet orbiting the red dwarf Kepler-186, about 500 light-years (178.5 parsecs, or nearly 5.0×1015 km) from the Earth. It is the first planet with a radius similar to Earth's to be discovered in the habitable zone of another star. NASA's Kepler space telescope detected it using the transit method, along with four additional planets orbiting much closer to the star (all modestly larger than Earth). Analysis of three years of data was required to find its signal. The results were presented initially at a conference on 19 March 2014 and some details were reported in the media at the time. The public announcement was on 17 April 2014, followed by publication in Science.
Kepler-442b is a confirmed near-Earth-sized exoplanet, likely rocky, orbiting within the habitable zone of the K-type main-sequence star Kepler-442, about 1,206 light-years, from Earth in the constellation Lyra. The planet was discovered by NASA's Kepler spacecraft using the transit method, in which the dimming effect that a planet causes as it crosses in front of its star is measured. NASA announced the confirmation of the exoplanet on 6 January 2015.
Kepler-1229b is a confirmed super-Earth exoplanet, likely rocky, orbiting within the habitable zone of the red dwarf Kepler-1229, located about 870 light years from Earth in the constellation of Cygnus. It was discovered in 2016 by the Kepler space telescope. The exoplanet was found by using the transit method, in which the dimming effect that a planet causes as it crosses in front of its star is measured.
The Large Ultraviolet Optical Infrared Surveyor, commonly known as LUVOIR, is a multi-wavelength space telescope concept being developed by NASA under the leadership of a Science and Technology Definition Team. It is one of four large astrophysics space mission concepts being studied in preparation for the National Academy of Sciences 2020 Astronomy and Astrophysics Decadal Survey. While LUVOIR is a concept for a general-purpose observatory, it has the key science goal of characterizing a wide range of exoplanets, including those that might be habitable. An additional goal is to enable a broad range of astrophysics, from the reionization epoch, through galaxy formation and evolution, to star and planet formation. Powerful imaging and spectroscopy observations of Solar System bodies would also be possible. LUVOIR would be a Large Strategic Science Mission and will be considered for a development start sometime after 2020. The LUVOIR Study Team has produced designs for two variants of LUVOIR: one with a 15 m diameter telescope mirror (LUVOIR-A) and one with an 8 m diameter mirror (LUVOIR-B). LUVOIR can observe ultraviolet, visible, and near-infrared wavelengths of light. The Final Report on the 5-year LUVOIR mission concept study was publicly released on 26 August 2019.
TRAPPIST-1e, also designated as 2MASS J23062928-0502285 e, is a solid, close-to-Earth-sized exoplanet orbiting within the habitable zone around the ultra-cool dwarf star TRAPPIST-1 approximately 40 light-years (12 parsecs), or nearly 3.7336×1014 km) away from Earth in the constellation of Aquarius. The exoplanet was found by using the transit method, in which the dimming effect that a planet causes as it crosses in front of its star is measured.
The Habitable Exoplanet Imaging Mission (HabEx) is a space telescope concept that would be optimized to search for and image Earth-size habitable exoplanets in the habitable zones of their stars, where liquid water can exist. HabEx would aim to understand how common terrestrial worlds beyond the Solar System may be and the range of their characteristics. It would be an optical, UV and infrared telescope that would also use spectrographs to study planetary atmospheres and eclipse starlight with either an internal coronagraph or an external starshade.
Origins Space Telescope (OST) is a concept study for a far-Infrared Surveyor space telescope mission. Still a preliminary concept in formulation, it will be presented to the United States Decadal Survey in 2019 for a possible selection to NASA's large strategic science missions. The OST would provide an array of new tools for studying star formation and the energetics and physical state of the interstellar medium within the Milky Way using infrared radiation and new spectroscopic capabilities.
Ross 128 b is a confirmed Earth-sized exoplanet, likely rocky, orbiting within the inner habitable zone of the red dwarf Ross 128, at a distance of about 11 light-years from Earth. The exoplanet was found using a decade's worth of radial velocity data using the European Southern Observatory's HARPS spectrograph at the La Silla Observatory in Chile. Ross 128 b is the nearest exoplanet around a quiet red dwarf, and is considered one of the best candidates for habitability. The planet is only 35% more massive than Earth, receives only 38% more sunlight, and is expected to be a temperature suitable for liquid water to exist on the surface, if it has an atmosphere.
Large Interferometer For Exoplanets (LIFE) is a project started in 2017 to develop the science, technology and a roadmap for a space mission to detect and characterize the atmospheres of dozens of warm, terrestrial extrasolar planets. The current plan is for a nulling interferometer operating in the mid-infrared consisting of several formation flying collector telescopes with a beam combiner spacecraft at their center.
