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F-type Main-sequence Stars
An F-type main-sequence star (F V) is a main-sequence, hydrogen-fusing star of spectral type F and luminosity class V. These stars have from 1.0 to 1.4 times the mass of the Sun and surface temperatures between 6,000 and 7,600 K.Tables VII and VIII. This temperature range gives the F-type stars a whitish hue when observed by the atmosphere. Because a main-sequence star is referred to as a dwarf star, this class of star may also be termed a yellow-white dwarf (not to be confused with white dwarfs, remnant stars that are a possible final stage of stellar evolution). Notable examples include Procyon A, Gamma Virginis A and B, and KIC 8462852. Spectral standard stars The revised Yerkes Atlas system (Johnson & Morgan 1953) listed a dense grid of F-type dwarf spectral standard stars; however, not all of these have survived to this day as stable standards. The ''anchor points'' of the MK spectral classification system among the F-type main-sequence dwarf stars, i.e. those standa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New Insights Into Debris Discs
New is an adjective referring to something recently made, discovered, or created. New or NEW may refer to: Music * New, singer of K-pop group The Boyz Albums and EPs * ''New'' (album), by Paul McCartney, 2013 * ''New'' (EP), by Regurgitator, 1995 Songs * "New" (Daya song), 2017 * "New" (Paul McCartney song), 2013 * "New" (No Doubt song), 1999 *"new", by Loona from '' Yves'', 2017 *"The New", by Interpol from ''Turn On the Bright Lights'', 2002 Acronyms * Net economic welfare, a proposed macroeconomic indicator * Net explosive weight, also known as net explosive quantity * Network of enlightened Women, a conservative university women's organization * Next Entertainment World, a South Korean film distribution company Identification codes * Nepal Bhasa language ISO 639 language code * New Century Financial Corporation (NYSE stock abbreviation) * Northeast Wrestling, a professional wrestling promotion in the northeastern United States Transport * New Orleans Lakefront Ai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Luminosity
Luminosity is an absolute measure of radiated electromagnetic power (light), the radiant power emitted by a light-emitting object over time. In astronomy, luminosity is the total amount of electromagnetic energy emitted per unit of time by a star, galaxy, or other astronomical object. In SI units, luminosity is measured in joules per second, or watts. In astronomy, values for luminosity are often given in the terms of the luminosity of the Sun, ''L''⊙. Luminosity can also be given in terms of the astronomical magnitude system: the absolute bolometric magnitude (''M''bol) of an object is a logarithmic measure of its total energy emission rate, while absolute magnitude is a logarithmic measure of the luminosity within some specific wavelength range or filter band. In contrast, the term ''brightness'' in astronomy is generally used to refer to an object's apparent brightness: that is, how bright an object appears to an observer. Apparent brightness depends on both the lumin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beta Virginis
Beta Virginis, a name Latinised from β Virginis, is a star in the equatorial constellation of Virgo. It has the proper name Zavijava (), and, despite its designation ' beta', is the fifth-brightest star in Virgo with an apparent visual magnitude of 3.604. The distance to this star is 35.7 light-years based on parallax, and it is drifting further away with a radial velocity of +4.1 km/s. It is 0.69 of a degree north of the ecliptic, so it can be occulted by the Moon and (rarely) by planets. The next planetary occultation of Beta Virginis will take place on 11 August 2069, by Venus. Properties This is an F-type main-sequence star with a stellar classification of F9 V, which means it is generating energy through core hydrogen fusion. Sun-like oscillations have been detected in Beta Virginis, allowing its internal structure to be modeled in more detail. It is around 2.9 billion years old with a projected rotational velocity of 4.3 km/s and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HR 1279
HR, Hr or hr may refer to: Arts and media Film and television * ''H.R. Pufnstuf'', a children's television series from 1969 * ''HR'', a 2013 television drama starring Alicia Silverstone * HR, a criminal organisation in the American TV series ''Person of Interest'' Other media * HR (girl group), Japan * Hessischer Rundfunk (Hessian Broadcasting), Germany * ''Homestar Runner'', an Internet cartoon * HyperRogue, a roguelike video game Fictional characters * H. R. Wells, a character from ''The Flash'' television series Business and finance * Human resources, personnel * Human resource management * Ukrainian hryvnia, currency Government and politics * Human rights * High Representative of the Union for Foreign Affairs and Security Policy of the European Union * United States House of Representatives Languages * hr (ISO 639-1 code) for the Croatian language * , a two-letter combination used in some languages ** Reduction of /hr/ to /r/ in Old/Middle English People * H.R. (bo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
78 Ursae Majoris
78 Ursae Majoris is a binary star system in the northern circumpolar constellation of Ursa Major. It is visible to the naked eye as a faint point of light with a combined apparent visual magnitude of 4.93. Parallax estimates by Hipparcos put it at a distance of , but it is drifting closer with a radial velocity of −5 km/s. The system is a candidate member of the Ursa Major Moving Group. The binary nature of this system was announced by S. W. Burnham in 1894. The pair orbit each other with a period of 105 years and an eccentricity of 0.39. Their semimajor axis has an angular size of and the orbital plane is inclined by 47°. The primary member, designated component A, has a magnitude of 5.02 and is an F-type main-sequence star with a stellar classification of F2V. It is 785 million years old and is spinning with a projected rotational velocity of 92 km/s. The star has 1.34 times the mass of the Sun and is radiating 5.75 times the Sun's luminosity fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
