RR Lyrae

Information about RR Lyrae

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AAVSO light curve of RR Lyrae. Different colors reflect different bandpasses.


RR Lyrae is a variable star in the Lyra constellation. It is the prototype of the RR Lyrae variables star class. It has a period of about 13 hours, and oscillates between apparent magnitudes 7 and 8. Its variable nature was discovered by the Scottish astronomer Williamina Fleming at Harvard Observatory in 1901. As RR Lyrae variables are important standard candles, knowing the precise distance of this star is necessary to determine its luminosity, and hence that of other stars in its class.

Its distance long uncertain, the Hubble Space Telescope's Fine Guidance Sensor was used in 2002 to determine the distance of RR Lyrae within ~5%: 262 parsecs, or 854 light-years. If accurate, this gives RR Lyrae an absolute magnitude of 0.61, roughly 49 times solar luminosity.

References

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Variable Star

Author Robert A. Heinlein & Spider Robinson
Cover artist Stephan Martiniere
Country United States
Language English
Genre(s) Science fiction
Publisher Tor Books
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Lyra

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List of stars in Lyra
Abbreviation: Lyr
Genitive: Lyrae
Symbology: the Lyre
Right ascension: 19 h
Declination: +40
Area: 286 sq. deg.
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RR Lyrae variables are variable stars often used as standard candles.

RR Lyrae are pulsating Horizontal branch stars, with a mass of around half the Sun's. RR Lyrae stars shed mass prior to becoming RR Lyrae and consequently, RR Lyrae were once stars with similar or slightly
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The apparent magnitude (m) of a celestial body is a measure of its brightness as seen by an observer on Earth, normalized to the value it would have in the absence of the atmosphere.
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Williamina Paton Stevens Fleming (May 15, 1857 – May 21, 1911), astronomer, was born in Dundee, Scotland, to Robert Stevens and Mary Walker Stevens. She attended public schools in Dundee, and at the age of 14, she became a pupil-teacher.
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Harvard College Observatory (or HCO) is an institution managing a complex of buildings and multiple instruments used for astronomical research by the Department of Astronomy of Harvard. It is located in Cambridge, Massachusetts, USA, and was founded in 1839.
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19th century - 20th century - 21st century
1870s  1880s  1890s  - 1900s -  1910s  1920s  1930s
1898 1899 1900 - 1901 - 1902 1903 1904

Year 1901 (MCMI
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A standard candle is an astronomical object that has a known luminosity. Several important methods of deriving distances in extragalactic astronomy and cosmology are based on standard candles.
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Luminosity has different meanings in several different fields of science.

In photometry and color imaging

Main article: luminance
In photometry, luminosity
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Hubble Space Telescope (HST) is a telescope in orbit around the Earth, named after astronomer Edwin Hubble. Its position outside the Earth's atmosphere provides significant advantages over ground-based telescopes — images are not blurred by the atmosphere, there is no
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Fine Guidance Sensor (FGS) is an interferometric instrument on board the Hubble Space Telescope (HST) that provides high-precision pointing information as input to the observatory's attitude control systems.
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20th century - 21st century - 22nd century
1970s  1980s  1990s  - 2000s -  2010s  2020s  2030s
1999 2000 2001 - 2002 - 2003 2004 2005

2002 by topic:
News by month
Jan - Feb - Mar - Apr - May - Jun
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parsec (symbol pc) is a unit of length used in astronomy. The length of the parsec is based on the method of trigonometric parallax, one of the oldest methods for measuring the distances to stars.
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1 light-year =
SI units
01015 m 01012 km
Astronomical units
0103 AU 0 pc
US customary / Imperial units
01015 ft 01012 mi
A light-year or lightyear (symbol:
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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. It allows the overall brightnesses of objects to be compared without regard to distance.
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Robert Burnham may refer to one of several people:
  • Robert Burnham, Jr. (1931-1993), author of Burnham's Celestial Handbook.
  • Robert Burnham (1947- ), a science writer at the Mars Space Flight Facility of Arizona State University.

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RR Lyrae variables are variable stars often used as standard candles.

RR Lyrae are pulsating Horizontal branch stars, with a mass of around half the Sun's. RR Lyrae stars shed mass prior to becoming RR Lyrae and consequently, RR Lyrae were once stars with similar or slightly
..... Click the link for more information.

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