Delta Scuti variable: Difference between revisions
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A '''Delta Scuti variable''' (sometimes termed ''dwarf cepheid'') is a [[variable star]] which exhibits variations in its [[luminosity]] due to both radial and non-radial pulsations of the star's surface. The variables are important [[standard candles]] and have been used to establish the distance to the [[Large Magellanic Cloud]], [[globular clusters]], [[open clusters]], and the [[Galactic center]].<ref name=mcnamara2000> |
A '''Delta Scuti variable''' (sometimes termed ''dwarf cepheid'') is a [[variable star]] which exhibits variations in its [[luminosity]] due to both radial and non-radial pulsations of the star's surface. The variables are important [[standard candles]] and have been used to establish the distance to the [[Large Magellanic Cloud]], [[globular clusters]], [[open clusters]], and the [[Galactic center]].<ref name=mcnamara2000> |
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McNamara, D. H.; Madsen, J. B.; Barnes, J.; Ericksen, B. F. (2000). [http://adsabs.harvard.edu/abs/2000PASP..112..202M ''The Distance to the Galactic Center''], PASP</ref><ref name=mcnamara2007>McNamara, D. Harold; Clementini, Gisella; Marconi, Marcella (2007). [http://adsabs.harvard.edu/abs/2007AJ....133.2752M ''The Distance to the Galactic Center''], AJ</ref><ref name=majaess2011>Majaess, D. J.; Turner, D. G.; Lane, D. J.; Henden, A. A.; Krajci, T. (2011). [http://adsabs.harvard.edu/abs/2011JAVSO..39..122M ''Anchoring the Universal Distance Scale Via a Wesenheit Template''], JAAVSO</ref><ref name=majaess2011b>Majaess, D. J.; Turner, D. G.; Lane, D. J.; Krajci, T. (2011). [http://adsabs.harvard.edu/cgi-bin/bib_query?arXiv:1102.1705 ''Deep Infrared ZAMS Fits to Benchmark Open Clusters Hosting Delta Scuti Stars''], JAAVSO</ref> The variables follow a period-luminosity relation in certain passbands like other [[standard candles]] such as [[Cepheids]].<ref name=poleski2010>Poleski, R.; Soszyñski, I.; Udalski, A.; Szymañski, M. K.; Kubiak, M.; Pietrzyñski, G.; Wyrzykowski, Ł.; Szewczyk, O.; Ulaczyk, K. (2010). [http://adsabs.harvard.edu/abs/2010AcA....60....1P ''The Optical Gravitational Lensing Experiment. The OGLE-III Catalog of Variable Stars. VI. Delta Scuti Stars in the Large Magellanic Cloud''], Acta Astronomica</ref><ref name=majaess2011/><ref name=majaess2011b/><ref name=cohen2012>Cohen, Roger E.; Sarajedini, Ata (2012). [http://adsabs.harvard.edu/abs/2012MNRAS.419..342C ''SX Phoenicis period-luminosity relations and the blue straggler connection''], MNRAS</ref> [[SX Phoenicis variables]] are generally considered to be a subclass of Delta Scuti variables that contain old stars, and can be found in globular clusters. SX Phe variables also follow a period-luminosity relation.<ref name=majaess2011/><ref name=cohen2012/> The recently discovered [[Rapidly oscillating Ap stars]] are also a subclass of Delta Scuti variables, found on the main sequence.<ref name=kopacki2003>Kopacki, G.; Kołaczkowski, Z.; Pigulski, A. (2003). [http://adsabs.harvard.edu/abs/2003A%26A...398..541K ''Variable stars in the globular cluster M 13''], Acta Astronomica</ref> One last sub-class are the pre-main sequence (PMS) Delta Scuti variables, and the name says it all. |
[[D. Harold McNamara|McNamara, D. H.]]; Madsen, J. B.; Barnes, J.; Ericksen, B. F. (2000). [http://adsabs.harvard.edu/abs/2000PASP..112..202M ''The Distance to the Galactic Center''], PASP</ref><ref name=mcnamara2007>[[D. Harold McNamara|McNamara, D. Harold]]; Clementini, Gisella; Marconi, Marcella (2007). [http://adsabs.harvard.edu/abs/2007AJ....133.2752M ''The Distance to the Galactic Center''], AJ</ref><ref name=majaess2011>Majaess, D. J.; Turner, D. G.; Lane, D. J.; Henden, A. A.; Krajci, T. (2011). [http://adsabs.harvard.edu/abs/2011JAVSO..39..122M ''Anchoring the Universal Distance Scale Via a Wesenheit Template''], JAAVSO</ref><ref name=majaess2011b>Majaess, D. J.; Turner, D. G.; Lane, D. J.; Krajci, T. (2011). [http://adsabs.harvard.edu/cgi-bin/bib_query?arXiv:1102.1705 ''Deep Infrared ZAMS Fits to Benchmark Open Clusters Hosting Delta Scuti Stars''], JAAVSO</ref> The variables follow a period-luminosity relation in certain passbands like other [[standard candles]] such as [[Cepheids]].<ref name=poleski2010>Poleski, R.; Soszyñski, I.; Udalski, A.; Szymañski, M. K.; Kubiak, M.; Pietrzyñski, G.; Wyrzykowski, Ł.; Szewczyk, O.; Ulaczyk, K. (2010). [http://adsabs.harvard.edu/abs/2010AcA....60....1P ''The Optical Gravitational Lensing Experiment. The OGLE-III Catalog of Variable Stars. VI. Delta Scuti Stars in the Large Magellanic Cloud''], Acta Astronomica</ref><ref name=majaess2011/><ref name=majaess2011b/><ref name=cohen2012>Cohen, Roger E.; Sarajedini, Ata (2012). [http://adsabs.harvard.edu/abs/2012MNRAS.419..342C ''SX Phoenicis period-luminosity relations and the blue straggler connection''], MNRAS</ref> [[SX Phoenicis variables]] are generally considered to be a subclass of Delta Scuti variables that contain old stars, and can be found in globular clusters. SX Phe variables also follow a period-luminosity relation.<ref name=majaess2011/><ref name=cohen2012/> The recently discovered [[Rapidly oscillating Ap stars]] are also a subclass of Delta Scuti variables, found on the main sequence.<ref name=kopacki2003>Kopacki, G.; Kołaczkowski, Z.; Pigulski, A. (2003). [http://adsabs.harvard.edu/abs/2003A%26A...398..541K ''Variable stars in the globular cluster M 13''], Acta Astronomica</ref> One last sub-class are the pre-main sequence (PMS) Delta Scuti variables, and the name says it all. |
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The [[OGLE]] and [[MACHO]] surveys have detected nearly 3000 Delta Scuti variables in the [[Large Magellanic Cloud]].<ref name=poleski2010/><ref name=garg2010> |
The [[OGLE]] and [[MACHO]] surveys have detected nearly 3000 Delta Scuti variables in the [[Large Magellanic Cloud]].<ref name=poleski2010/><ref name=garg2010> |
Revision as of 15:55, 28 June 2013
A Delta Scuti variable (sometimes termed dwarf cepheid) is a variable star which exhibits variations in its luminosity due to both radial and non-radial pulsations of the star's surface. The variables are important standard candles and have been used to establish the distance to the Large Magellanic Cloud, globular clusters, open clusters, and the Galactic center.[1][2][3][4] The variables follow a period-luminosity relation in certain passbands like other standard candles such as Cepheids.[5][3][4][6] SX Phoenicis variables are generally considered to be a subclass of Delta Scuti variables that contain old stars, and can be found in globular clusters. SX Phe variables also follow a period-luminosity relation.[3][6] The recently discovered Rapidly oscillating Ap stars are also a subclass of Delta Scuti variables, found on the main sequence.[7] One last sub-class are the pre-main sequence (PMS) Delta Scuti variables, and the name says it all.
The OGLE and MACHO surveys have detected nearly 3000 Delta Scuti variables in the Large Magellanic Cloud.[5][8] Typical brightness fluctuations are from 0.003 to 0.9 magnitudes in V over a period of a few hours, although the amplitude and period of the fluctuations can vary greatly. The stars are usually A0 to F5 type giant or main sequence stars. The high-amplitude Delta Scuti variables are also called AI Velorum stars. They are the second most abundant variable source in the Milky Way after white dwarfs.
The prototype of these sorts of variable stars is Delta Scuti, which exhibits brightness fluctuations from +4.60 to +4.79 in apparent magnitude with a period of 4.65 hours. Other well known Delta Scuti variables include Altair, Denebola (
References
- ^ McNamara, D. H.; Madsen, J. B.; Barnes, J.; Ericksen, B. F. (2000). The Distance to the Galactic Center, PASP
- ^ McNamara, D. Harold; Clementini, Gisella; Marconi, Marcella (2007). The Distance to the Galactic Center, AJ
- ^ a b c Majaess, D. J.; Turner, D. G.; Lane, D. J.; Henden, A. A.; Krajci, T. (2011). Anchoring the Universal Distance Scale Via a Wesenheit Template, JAAVSO
- ^ a b Majaess, D. J.; Turner, D. G.; Lane, D. J.; Krajci, T. (2011). Deep Infrared ZAMS Fits to Benchmark Open Clusters Hosting Delta Scuti Stars, JAAVSO
- ^ a b Poleski, R.; Soszyñski, I.; Udalski, A.; Szymañski, M. K.; Kubiak, M.; Pietrzyñski, G.; Wyrzykowski, Ł.; Szewczyk, O.; Ulaczyk, K. (2010). The Optical Gravitational Lensing Experiment. The OGLE-III Catalog of Variable Stars. VI. Delta Scuti Stars in the Large Magellanic Cloud, Acta Astronomica
- ^ a b Cohen, Roger E.; Sarajedini, Ata (2012). SX Phoenicis period-luminosity relations and the blue straggler connection, MNRAS
- ^ Kopacki, G.; Kołaczkowski, Z.; Pigulski, A. (2003). Variable stars in the globular cluster M 13, Acta Astronomica
- ^
Garg, A.; Cook, K. H.; Nikolaev, S.; Huber, M. E.; Rest, A.; Becker, A. C.; Challis, P.; Clocchiatti, A.; Miknaitis, G.; Minniti, D.; Morelli, L.; Olsen, K.; Prieto, J. L.; Suntzeff, N. B.; Welch, D. L.; Wood-Vasey, W. M. (2010). High-amplitude
δ -Scutis in the Large Magellanic Cloud, AJ
- Samus N.N., Durlevich O.V., et al. Combined General Catalog of Variable Stars (GCVS4.2, 2004 Ed.)
- AI Velorum star at The Encyclopedia of Astrobiology, Astronomy, and Spaceflight
- AAVSO: Delta Scuti and the Delta Scuti variables