SY Equulei (original) (raw)
SY Equulei, also known as HD 203664, is a single variable star located in the equatorial constellation Equuleus. It has an average apparent magnitude of about 8.5, varying by a few hundredths of a magnitude, making it readily visible in binoculars and small telescopes, but not to the naked eye. The star is relatively far away at a distance of 8,000 light years and is receding with a heliocentric radial velocity of 48 km/s. At that distance, SY Equulei is dimmed by 0.19 magnitudes due to interstellar dust.
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| dbo:abstract | SY Equulei, also known as HD 203664, is a single variable star located in the equatorial constellation Equuleus. It has an average apparent magnitude of about 8.5, varying by a few hundredths of a magnitude, making it readily visible in binoculars and small telescopes, but not to the naked eye. The star is relatively far away at a distance of 8,000 light years and is receding with a heliocentric radial velocity of 48 km/s. At that distance, SY Equulei is dimmed by 0.19 magnitudes due to interstellar dust. Throughout the late 20th century, HD 203664 was known to have a dust cloud surrounding it. Subsequent observations from Kenneth R. Sembach (1995) reveal it to contain high abundances of calcium as well as traces of magnesium, aluminum, and silicon. The cloud probably came from outside the galactic plane and is moving towards the star at a rate of 70 km/s. The star has a high galactic latitude, indicating its location in the galactic halo. HD 203664 was most likely ejected from its birthplace to its current distance. However, its status as a Beta Cephei variable wasn't discovered until a survey of 2000 using Hipparcos data. It was then given the designation SY Equulei. SY Equulei has a stellar classification of B0.5 IIIn, indicating an evolved B-type star with nebulous (broad) absorption lines due to rapid rotation. Unlike most stars of its type, it spins rapidly with a projected rotational velocity of 180 km/s, which is 40% of its break-up velocity. It has 14 times the mass of the Sun and a radius of 10.4 radius. It radiates at 2,490 times the luminosity of the Sun from its photosphere at an effective temperature of 28,184 K, giving a whitish blue hue. SY Equueli is a variable star with an amplitude of 0.07 magnitudes and an average period of 3.98 hours. In later observations, SY Equulei was found to have multiple periods. (en) |
| dbo:thumbnail | wiki-commons:Special:FilePath/SYEquLightCurve.png?width=300 |
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| dbo:wikiPageRevisionID | 1102782110 (xsd:integer) |
| dbo:wikiPageWikiLink | dbr:Calcium dbr:B-type_star dbr:Beta_Cephei_variable dbr:Stellar_classification dbr:Light_curve dbc:B-type_giants dbc:Beta_Cephei_variables dbc:Durchmusterung_objects dbc:Henry_Draper_Catalogue_objects dbc:Hipparcos_objects dbc:Objects_with_variable_star_designations dbr:Constellation dbr:Naked_eye dbr:Photosphere dbr:Effective_temperature dbr:Apparent_magnitude dbr:Light_year dbr:Magnesium dbr:Hours dbr:Galactic_halo dbr:Aluminum dbc:Equuleus dbr:Equuleus dbr:Kenneth_R._Sembach dbr:Radius dbr:Hipparcos dbr:International_Celestial_Reference_System dbr:J2000.0 dbr:Telescopes dbr:Radial_velocity dbr:Silicon dbr:Variable_star dbr:Variable_star_designation dbr:Mass_of_the_Sun dbr:Galactic_latitude dbr:Break-up_velocity dbr:Absorption_lines dbr:Projected_rotational_velocity dbr:Luminosity_of_the_Sun dbr:File:SYEquLightCurve.png |
| dbp:absmagBol | −6.04 (en) |
| dbp:ageMyr | ~7.5 (en) |
| dbp:appmagV | 8.520000 (xsd:double) |
| dbp:bV | −0.20 (en) |
| dbp:class | B0.5 IIIn (en) |
| dbp:constell | dbr:Equuleus |
| dbp:epoch | J2000.0 (en) |
| dbp:gravity | 3.800000 (xsd:double) |
| dbp:luminosity | 2490 (xsd:integer) |
| dbp:mass | 14 (xsd:integer) |
| dbp:metalFe | 0 (xsd:integer) |
| dbp:pError | 0.055800 (xsd:double) |
| dbp:parallax | 0.386900 (xsd:double) |
| dbp:propMoDec | −9.049 (en) |
| dbp:propMoRa | −0.185 (en) |
| dbp:radialV | 48 (xsd:integer) |
| dbp:radius | 10.440000 (xsd:double) |
| dbp:rotationalVelocity | 180 (xsd:integer) |
| dbp:temperature | 28184 (xsd:integer) |
| dbp:uB | −1.00 (en) |
| dbp:variable | dbr:Beta_Cephei_variable |
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| dcterms:subject | dbc:B-type_giants dbc:Beta_Cephei_variables dbc:Durchmusterung_objects dbc:Henry_Draper_Catalogue_objects dbc:Hipparcos_objects dbc:Objects_with_variable_star_designations dbc:Equuleus |
| rdf:type | owl:Thing dbo:Place dbo:Location schema:Place dbo:CelestialBody dbo:Star |
| rdfs:comment | SY Equulei, also known as HD 203664, is a single variable star located in the equatorial constellation Equuleus. It has an average apparent magnitude of about 8.5, varying by a few hundredths of a magnitude, making it readily visible in binoculars and small telescopes, but not to the naked eye. The star is relatively far away at a distance of 8,000 light years and is receding with a heliocentric radial velocity of 48 km/s. At that distance, SY Equulei is dimmed by 0.19 magnitudes due to interstellar dust. (en) |
| rdfs:label | SY Equulei (en) |
| owl:sameAs | wikidata:SY Equulei https://global.dbpedia.org/id/GQp55 |
| prov:wasDerivedFrom | wikipedia-en:SY_Equulei?oldid=1102782110&ns=0 |
| foaf:depiction | wiki-commons:Special:FilePath/SYEquLightCurve.png |
| foaf:isPrimaryTopicOf | wikipedia-en:SY_Equulei |
| foaf:name | SY Equulei (en) |
| is dbo:wikiPageRedirects of | dbr:HD_203664 |
| is dbo:wikiPageWikiLink of | dbr:HD_203664 dbr:List_of_stars_in_Equuleus |
| is foaf:primaryTopic of | wikipedia-en:SY_Equulei |
