Delta Cephei (δ Cep / δ Cephei) is a star in the constellation Cepheus. From the Glossary of Astronomical Terms by the Harvard-Smithsonian Center for Astrophysics: Either of the two points (vernal, autumnal) on the celestial sphere where the ecliptic (which is the apparent path of the sun on the sky) intersects the celestial equator. ... This article or section does not cite its references or sources. ... Cepheus (IPA: ) is a northern constellation named after King Cepheus in Greek mythology, and is considered to represent a king. ... Equatorial Coordinates Right ascension (abbrev. ... In astronomy, declination (abbrev. ... // Headline text HEY!! HOW ARE YOU ALL?? Its nice of you to come read this page. ... In astronomy, stellar classification is a classification of stars based initially on photospheric temperature and its associated spectral characteristics, and subsequently refined in terms of other characteristics. ... In astronomy, the color index is a simple numerical expression that determines the color of an object, which in the case of a star gives its temperature. ... In astronomy, the color index is a simple numerical expression that determines the color of an object, which in the case of a star gives its temperature. ... Most stars are of almost constant luminosity. ... Cepheid in the Spiral Galaxy M100 A Cepheid variable or Cepheid is a member of a particular class of variable stars, notable for a fairly tight correlation between their period of variability and absolute luminosity. ... Illustration of the use of optical wavelength interferometry to determine precise positions of stars. ... Radial velocity is the velocity of an object in the direction of the line of sight. ... kilometre per second is an SI derived unit of both speed (scalar) and velocity (vector), signified by the symbol km/s or km s-1. ... The proper motion of a star is the motion of the position of the star in the sky (the change in direction in which we see it, as opposed to the radial velocity) after eliminating the improper motions of the stars, which affect their measured coordinates but are not real... A milliarcsecond (m, mas) , or a thoundsanth of an arcsecond. ... A year is the time between two recurrences of an event related to the orbit of the Earth around the Sun. ... A milliarcsecond (m, mas) , or a thoundsanth of an arcsecond. ... A year is the time between two recurrences of an event related to the orbit of the Earth around the Sun. ... This does not adequately cite its references or sources. ... A milliarcsecond (m, mas) , or a thoundsanth of an arcsecond. ... Distance is a numerical description of how far apart things lie. ... A light-year or lightyear (symbol: ly) is a unit of measurement of length, specifically the distance light travels in vacuum in one Julian year. ... Stellar parallax motion The parsec (symbol pc) is a unit of length used in astronomy. ... In astronomy, absolute magnitude is the apparent magnitude, m, an object would have if it were at a standard luminosity distance away from us, in the absence of interstellar extinction. ... Unsolved problems in physics: What causes anything to have mass? The U.S. National Prototype Kilogram, which currently serves as the primary standard for measuring mass in the U.S. Mass is the property of a physical object that quantifies the amount of matter and energy it is equivalent to. ... In astronomy, the solar mass is a unit of mass used to express the mass of stars and larger objects such as galaxies. ... Remote Authentication Dial In User Service (RADIUS) is an AAA (authentication, authorization and accounting) protocol for applications such as network access or IP mobility. ... In astronomy, the solar radius is a unit of length used to express the size of stars and larger objects such as galaxies. ... Luminosity has different meanings in several different fields of science. ... The solar luminosity, , is a unit of luminosity (power emitted in the form of photons) conventionally used by astronomers to give the luminosities of stars. ... Fig. ... The Kelvin scale is a thermodynamic (absolute) temperature scale where absolute zero—the lowest possible temperature where nothing could be colder and no heat energy remains in a substance—is defined as zero kelvin (0 K). ... The globular cluster M80. ... A sphere rotating around its axis. ... This article is about the astronomical object. ... A year is the time between two recurrences of an event related to the orbit of the Earth around the Sun. ... In astronomy, many stars are referred to simply by catalogue numbers. ... In astronomy, many stars are referred to simply by catalogue numbers. ... In astronomy, many stars are referred to simply by catalogue numbers. ... The Henry Draper Catalogue is an astronomy catalogue with astrometric and spectroscopic data about more than 225,000 stars. ... Smithsonian Astrophysical Observatory Star Catalog contain the 258,996 stars. ... Fifth Fundamental Catalogue is a glossary of positions of stars. ... The Hipparcos and Tycho Catalogues (Tycho-1) are the primary products of the European Space Agencys astrometric mission, Hipparcos. ... This article is about the astronomical object. ... This article or section does not cite its references or sources. ... Cepheus (IPA: ) is a northern constellation named after King Cepheus in Greek mythology, and is considered to represent a king. ...

Delta Cephei is the prototype of the Cepheid variables, hence its Latin proper name Cepheidus Prototypus, and it is also the closest star of this type to the Sun. Its variability was discovered by John Goodricke in 1784, the second Cepheid variable discovered following Eta Aquilae earlier the same year. Cepheid in the Spiral Galaxy M100 A Cepheid variable or Cepheid is a member of a particular class of variable stars, notable for a fairly tight correlation between their period of variability and absolute luminosity. ... Latin is an ancient Indo-European language originally spoken in Latium, the region immediately surrounding Rome. ... The Sun is the star at the center of the Solar System. ... John Goodricke (September 17, 1764 – April 20, 1786) was an amateur astronomer. ... 1784 was a leap year starting on Thursday (see link for calendar). ... Eta Aquilae (η Aql / η Aquilae) is a star in the constellation Aquila. ...

Unlike the eclipsing binary Algol, Delta Cephei's variability is due to pulsation of the star. It varies from magnitude 3.6 to 4.3, and its spectral type also varies, from about F5 to G3. The period is 5.36634 days; rise to maximum is quicker than the subsequent decline to minimum. It was later discovered that there are two types of Cepheid variables, and Delta Cephei is now known as a type I (Classical) Cepheid. Animation showing how an eclipsing binary stars light intensity changes as they orbit An eclipsing binary star is a binary star in which the orbit plane of the two stars lies so nearly in the line of sight of the observer that the components undergo mutual eclipses. ... ALGOL (short for ALGOrithmic Language) is a family of imperative computer programming languages originally developed in the mid 1950s which became the de facto standard way to report algorithms in print for almost the next 30 years. ... // Headline text HEY!! HOW ARE YOU ALL?? Its nice of you to come read this page. ... In astronomy, stellar classification is a classification of stars based initially on photospheric temperature and its associated spectral characteristics, and subsequently refined in terms of other characteristics. ...

Stars of this type are believed to form with masses of 3–30 times that of our Sun, and then have passed through the main sequence as B-class stars. With the hydrogen burnt up in their core, these unstable stars are now passing through later stages of nuclear burning.^[2] The Sun is the star at the center of the Solar System. ... Hertzsprung-Russell diagram The main sequence of the Hertzsprung-Russell diagram is the curve where the majority of stars are located in this diagram. ... This article is about the chemistry of hydrogen. ...

Knowing the distance of Delta Cephei and others in its class is fundamental to calibrating their period-luminosity relationship; unfortunately, these efforts were until recently marred by only fair parallax accuracy. In 2002 however, the Hubble Space Telescope was used to determine the distance to Delta Cephei (and RR Lyrae, another standard candle) within ~4%: 273 parsecs, or 890 light-years.^[3] log(P)+0. ... This does not adequately cite its references or sources. ... For album titles with the same name, see 2002 (album). ... The Hubble Space Telescope (HST) is a telescope in orbit around the Earth, named after astronomer Edwin Hubble. ... RR Lyrae is a variable star in the Lyra constellation. ... A standard candle is an astronomical object that has a known luminosity. ...

There is a companion star, separated from Delta Cephei by 41 arc seconds. A second of arc or arcsecond is a unit of angular measurement which comprises one-sixtieth of an arcminute, or 1/3600 of a degree of arc or 1/1296000 ≈ 7. ...

References

1. ^ "Database of Galactic Classical Cepheids", David Dunlop Observatory, 1995.
2. ^ Turner, David G, "Monitoring the Evolution of Cepheid Variables", Journal of the AAVSO, 26, 1998, 101-111.
3. ^ Benedict, et al., "Astrometry with the Hubble space telescope: a parallax of the fundamental distance calibrator δ Cephei"

External links

• Alcyone ephemeris.
• SEDS page.
• Delta Cephei by Professor Jim Kaler.
• AAVSO variable star of the month.