59 relations: Apparent magnitude, Apsis, Asteroid belt, Astronomical unit, Barney and Betty Hill, Bayer designation, Beryllium, Binary star, Bortle scale, Bright Star Catalogue, Brown dwarf, Chromosphere, Constellation, Debris disk, Double star, Durchmusterung, Earth, Epoch (astronomy), Exoplanet, Extraterrestrial life, Flamsteed designation, Galactic Center, Galactic coordinate system, Gliese Catalogue of Nearby Stars, Grey alien, Henry Draper Catalogue, Herschel Space Observatory, Hertzsprung–Russell diagram, Hipparcos, Horologium (constellation), Hot Jupiter, Infrared excess, John Flamsteed, Kuiper belt, Large Magellanic Cloud, Luminosity, Main sequence, Metallicity, Milky Way, Minute and second of arc, Nicolas-Louis de Lacaille, Orbital eccentricity, Orbital inclination, Parallax, Planetary objects proposed in religion, astrology, ufology and pseudoscience, Reticulum, Semi-major and semi-minor axes, Small Magellanic Cloud, Smithsonian Astrophysical Observatory Star Catalog, Solar analog, ..., Solar mass, Solar radius, Spitzer Space Telescope, Star catalogue, Stellar classification, Stellar kinematics, Thick disk, Washington Double Star Catalog, Zeta Herculis Moving Group. Expand index (9 more) » « Shrink index
The apparent magnitude of a celestial object is a number that is a measure of its brightness as seen by an observer on Earth.
An apsis (ἁψίς; plural apsides, Greek: ἁψῖδες) is an extreme point in the orbit of an object.
The asteroid belt is the circumstellar disc in the Solar System located roughly between the orbits of the planets Mars and Jupiter.
The astronomical unit (symbol: au, ua, or AU) is a unit of length, roughly the distance from Earth to the Sun.
Barney and Betty Hill were an American couple who claimed they were abducted by extraterrestrials in a rural portion of the state of New Hampshire from September 19 to September 20, 1961.
A Bayer designation is a stellar designation in which a specific star is identified by a Greek letter, followed by the genitive form of its parent constellation's Latin name.
Beryllium is a chemical element with symbol Be and atomic number 4.
A binary star is a star system consisting of two stars orbiting around their common barycenter.
The Bortle scale is a nine-level numeric scale that measures the night sky's brightness of a particular location.
The Bright Star Catalogue, also known as the Yale Catalogue of Bright Stars or Yale Bright Star Catalogue, is a star catalogue that lists all stars of stellar magnitude 6.5 or brighter, which is roughly every star visible to the naked eye from Earth.
Brown dwarfs are substellar objects that occupy the mass range between the heaviest gas giant planets and the lightest stars, having masses between approximately 13 to 75–80 times that of Jupiter, or approximately to about.
The chromosphere (literally, "sphere of color") is the second of the three main layers in the Sun's atmosphere and is roughly 3,000 to 5,000 kilometers deep.
A constellation is a group of stars that are considered to form imaginary outlines or meaningful patterns on the celestial sphere, typically representing animals, mythological people or gods, mythological creatures, or manufactured devices.
A debris disk is a circumstellar disk of dust and debris in orbit around a star.
In observational astronomy, a double star or visual double is a pair of stars that appear close to each other in the sky as seen from Earth when viewed through an optical telescope.
In astronomy, Durchmusterung or Bonner Durchmusterung (BD), is the comprehensive astrometric star catalogue of the whole sky, compiled by the Bonn Observatory (Germany) from 1859 to 1903.
Earth is the third planet from the Sun and the only astronomical object known to harbor life.
In astronomy, an epoch is a moment in time used as a reference point for some time-varying astronomical quantity, such as the celestial coordinates or elliptical orbital elements of a celestial body, because these are subject to perturbations and vary with time.
An exoplanet or extrasolar planet is a planet outside our solar system.
Extraterrestrial life,Where "extraterrestrial" is derived from the Latin extra ("beyond", "not of") and terrestris ("of Earth", "belonging to Earth").
A Flamsteed designation is a combination of a number and constellation name that uniquely identifies most naked eye stars in the modern constellations visible from southern England.
The Galactic Center is the rotational center of the Milky Way.
The galactic coordinate system is a celestial coordinate system in spherical coordinates, with the Sun as its center, the primary direction aligned with the approximate center of the Milky Way galaxy, and the fundamental plane parallel to an approximation of the galactic plane but offset to its north.
The Gliese Catalogue of Nearby Stars is a modern star catalogue of stars located within 25 parsecs (81.54 ly) of the Earth.
Grey aliens, also referred to as "Alien Greys", "Greys", "Grays" and "Roswell Greys", allegedly are extraterrestrial beings whose existence is discussed in ufological, paranormal, and New Age communities, and who are named for their unique skin color.
The Henry Draper Catalogue (HD) is an astronomical star catalogue published between 1918 and 1924, giving spectroscopic classifications for 225,300 stars; it was later expanded by the Henry Draper Extension (HDE), published between 1925 and 1936, which gave classifications for 46,850 more stars, and by the Henry Draper Extension Charts (HDEC), published from 1937 to 1949 in the form of charts, which gave classifications for 86,933 more stars.
The Herschel Space Observatory was a space observatory built and operated by the European Space Agency (ESA).
The Hertzsprung–Russell diagram, abbreviated H–R diagram, HR diagram or HRD, is a scatter plot of stars showing the relationship between the stars' absolute magnitudes or luminosities versus their stellar classifications or effective temperatures.
Hipparcos was a scientific satellite of the European Space Agency (ESA), launched in 1989 and operated until 1993.
Horologium is a faint constellation in the southern sky.
Hot Jupiters are a class of gas giant exoplanets that are inferred to be physically similar to Jupiter but that have very short orbital period (P The close proximity to their stars and high surface-atmosphere temperatures resulted in the moniker "hot Jupiters". Hot Jupiters are the easiest extrasolar planets to detect via the radial-velocity method, because the oscillations they induce in their parent stars' motion are relatively large and rapid compared to those of other known types of planets. One of the best-known hot Jupiters is 51 Pegasi b. Discovered in 1995, it was the first extrasolar planet found orbiting a Sun-like star. 51 Pegasi b has an orbital period of about 4 days.
An infrared excess is a measurement of an astronomical source, typically a star, that in their spectral energy distribution has a greater measured infrared flux than expected by assuming the star is a blackbody radiator.
John Flamsteed FRS (19 August 1646 – 31 December 1719) was an English astronomer and the first Astronomer Royal.
The Kuiper belt, occasionally called the Edgeworth–Kuiper belt, is a circumstellar disc in the outer Solar System, extending from the orbit of Neptune (at 30 AU) to approximately 50 AU from the Sun.
The Large Magellanic Cloud (LMC) is a satellite galaxy of the Milky Way.
In astronomy, luminosity is the total amount of energy emitted per unit of time by a star, galaxy, or other astronomical object.
In astronomy, the main sequence is a continuous and distinctive band of stars that appear on plots of stellar color versus brightness.
In astronomy, metallicity is used to describe the abundance of elements present in an object that are heavier than hydrogen or helium.
The Milky Way is the galaxy that contains our Solar System.
A minute of arc, arcminute (arcmin), arc minute, or minute arc is a unit of angular measurement equal to of one degree.
Abbé Nicolas-Louis de Lacaille, formerly sometimes spelled de la Caille, (15 March 1713 – 21 March 1762) was a French astronomer.
The orbital eccentricity of an astronomical object is a parameter that determines the amount by which its orbit around another body deviates from a perfect circle.
Orbital inclination measures the tilt of an object's orbit around a celestial body.
Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight, and is measured by the angle or semi-angle of inclination between those two lines.
There are a number of planets or moons whose existence is not supported by scientific evidence, but are proposed by various astrologers, pseudoscientists, conspiracy theorists, or certain religious groups.
Reticulum is a small, faint constellation in the southern sky.
In geometry, the major axis of an ellipse is its longest diameter: a line segment that runs through the center and both foci, with ends at the widest points of the perimeter.
The Small Magellanic Cloud (SMC), or Nubecula Minor, is a dwarf galaxy near the Milky Way.
The Smithsonian Astrophysical Observatory Star Catalog is an astrometric star catalogue.
Solar-type star, solar analogs (also analogues), and solar twins are stars that are particularly similar to the Sun.
The solar mass is a standard unit of mass in astronomy, equal to approximately.
Solar radius is a unit of distance used to express the size of stars in astronomy.
The Spitzer Space Telescope (SST), formerly the Space Infrared Telescope Facility (SIRTF), is an infrared space telescope launched in 2003 and still operating as of 2018.
A star catalogue (Commonwealth English) or star catalog (American English), is an astronomical catalogue that lists stars.
In astronomy, stellar classification is the classification of stars based on their spectral characteristics.
In astronomy, stellar kinematics is the observational study or measurement of the kinematics or motions of stars through space.
The thick disk is one of the structural components of about 2/3 of all disk galaxies, including the Milky Way.
The Washington Double Star Catalog, or WDS, is a catalog of double stars, maintained at the United States Naval Observatory.
Zeta Herculis Moving Group is a set of stars that share a common motion through space.
GJ 136, GJ 138, Gl 136, Gl 138, Gliese 136, Gliese 138, HD 20766, HD 20807, Zeta Ret, Zeta Reticulans, Zeta Retuculi, Zeta reticuli, Zeta1 Ret, Zeta1 Reticuli, Zeta2 Ret, Zeta2 Reticuli, Ζ Ret, Ζ Reticuli, Ζ1 Ret, Ζ1 Reticuli, Ζ2 Ret, Ζ2 Reticuli.