BE Ursae Majoris (original) (raw)
おおぐま座BE星（BE Ursae Majoris、BE UMa）は、おおぐま座の方角、地球からおよそ7,000光年の距離にある食変光星である。
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|---|---|
| dbo:abstract | BE Ursae Majoris is a binary star system in the northern circumpolar constellation of Ursa Major, abbreviated BE UMa. The two components are an unusual M-class dwarf star and a subdwarf O star, borderline white dwarf. It is classified as a detached Algol variable and ranges in brightness from an apparent visual magnitude of 14.8 down to 17.8. This is too faint to be visible to the naked eye. The distance to this system is approximately 4,600 light years based on parallax measurements. The variability of SVS 1424 was announced in 1964 by N. E. Kurochkin from Sternberg, and was found to have a period of 2.291 days while ranging in brightness from magnitude 14.1 down to 15.6. After being assigned the variable star designation BE UMa, it was discovered to be a source of hot ultraviolet emission with a helium-rich spectrum by and associates in 1981. and associates found variability of spectral features on a time scale as low as a few hours. They interpreted this as a detached binary system consisting of a compact, high temperature white dwarf and a cool red dwarf star. The outer layers of the cooler star are being ionized by radiation from the hotter component, and the changing orientation of this heated region over the course of an orbit is creating a sinusoidal variability of about 1.5 magnitudes. In 1982, a deep eclipse was discovered in the light curve by and associates. This put a strong limit on the possible models for the system, which indicated that the compact component is a hot O-type subdwarf. and associates in 1983 found that the temperature and radius of the cool component suggested that it is an evolved subgiant star. At present, no mass transfer is taking place, but the system appears to be evolving into a cataclysmic variable as the subdwarf cools to become a normal white dwarf. In 1995, and associates discovered that the system is surrounded by a planetary nebula with a diameter of 3′, which was likely shed when the present day subdwarf was leaving the asymptotic giant branch stage. The two components would have shared a common envelope as little as 10,000 years ago. As a result, rather than being a subgiant, the cool component has not yet reached the thermal equilibrium of a late dwarf star. The pair have a circular orbit with a period of 2.2911658 days and a separation of 7.5±0.5 R☉. The orbital plane is inclined at an angle of 84°±1° to the line of sight from the Earth. (en) おおぐま座BE星（BE Ursae Majoris、BE UMa）は、おおぐま座の方角、地球からおよそ7,000光年の距離にある食変光星である。 (ja) BE Большой Медведицы (лат. BE Ursae Majoris) — двойная затменная переменная звезда типа Алголя (EA) в созвездии Близнецов на расстоянии приблизительно 5412 световых лет (около 1659 парсеков) от Солнца. Видимая звёздная величина звезды — от +17,8m до +14,8m. Орбитальный период — около 2,2912 суток. (ru) |
| dbo:thumbnail | wiki-commons:Special:FilePath/BEUMaLightCurve.png?width=300 |
| dbo:wikiPageID | 71881524 (xsd:integer) |
| dbo:wikiPageLength | 13776 (xsd:nonNegativeInteger) |
| dbo:wikiPageRevisionID | 1113469684 (xsd:integer) |
| dbo:wikiPageWikiLink | dbr:Binary_star dbr:Algol_variable dbr:Ursa_Major dbr:Light_curve dbr:Late-type_star dbc:Algol_variables dbc:M-type_main-sequence_stars dbc:Objects_with_variable_star_designations dbc:Ursa_Major_(constellation) dbc:White_dwarfs dbr:Orbital_plane dbr:Light_year dbr:Stellar_evolution dbr:Common_envelope dbr:Detached_binary dbr:Orbital_period dbr:Stellar_parallax dbc:O-type_subdwarfs dbr:White_dwarf dbr:Subdwarf_O_star dbr:Asymptotic_giant_branch dbr:Eclipse dbr:Red_dwarf dbr:Planetary_nebula dbr:Circumpolar_constellation dbr:Apparent_visual_magnitude dbr:Sternberg_Astronomical_Institute dbr:Variable_star_designation dbr:Sinusoidal dbr:Subgiant_star dbr:Detached_binaries dbr:Cataclysmic_variable dbr:Bruce_Margon dbr:David_Crampton dbr:Donald_H._Ferguson dbr:File:BEUMaLightCurve.png dbr:Hiroyasu_Ando dbr:James_Liebert |
| dbp:class | (en) DO + M1e–M5e (en) |
| dbp:component | M class dwarf (en) Subdwarf O star (en) |
| dbp:constell | dbr:Ursa_Major |
| dbp:epoch | J2000 (en) |
| dbp:gravity | 6.500000 (xsd:double) |
| dbp:mass | 0.250000 (xsd:double) 0.590000 (xsd:double) |
| dbp:pError | 0.025700 (xsd:double) |
| dbp:parallax | 0.707900 (xsd:double) |
| dbp:propMoDec | −12.783 (en) |
| dbp:propMoRa | 10.706000 (xsd:double) |
| dbp:radialV | −67 (en) |
| dbp:radius | 0.078000 (xsd:double) 0.720000 (xsd:double) |
| dbp:temperature | 4750 (xsd:integer) |
| dbp:variable | dbr:Algol_variable dbr:Detached_binaries |
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| dcterms:subject | dbc:Algol_variables dbc:M-type_main-sequence_stars dbc:Objects_with_variable_star_designations dbc:Ursa_Major_(constellation) dbc:White_dwarfs dbc:O-type_subdwarfs |
| rdf:type | owl:Thing dbo:Place dbo:Location schema:Place dbo:CelestialBody dbo:Star |
| rdfs:comment | おおぐま座BE星（BE Ursae Majoris、BE UMa）は、おおぐま座の方角、地球からおよそ7,000光年の距離にある食変光星である。 (ja) BE Большой Медведицы (лат. BE Ursae Majoris) — двойная затменная переменная звезда типа Алголя (EA) в созвездии Близнецов на расстоянии приблизительно 5412 световых лет (около 1659 парсеков) от Солнца. Видимая звёздная величина звезды — от +17,8m до +14,8m. Орбитальный период — около 2,2912 суток. (ru) BE Ursae Majoris is a binary star system in the northern circumpolar constellation of Ursa Major, abbreviated BE UMa. The two components are an unusual M-class dwarf star and a subdwarf O star, borderline white dwarf. It is classified as a detached Algol variable and ranges in brightness from an apparent visual magnitude of 14.8 down to 17.8. This is too faint to be visible to the naked eye. The distance to this system is approximately 4,600 light years based on parallax measurements. (en) |
| rdfs:label | BE Ursae Majoris (en) おおぐま座BE星 (ja) BE Большой Медведицы (ru) |
| owl:sameAs | wikidata:BE Ursae Majoris dbpedia-ja:BE Ursae Majoris dbpedia-ru:BE Ursae Majoris https://global.dbpedia.org/id/4VKWG |
| prov:wasDerivedFrom | wikipedia-en:BE_Ursae_Majoris?oldid=1113469684&ns=0 |
| foaf:depiction | wiki-commons:Special:FilePath/BEUMaLightCurve.png |
| foaf:isPrimaryTopicOf | wikipedia-en:BE_Ursae_Majoris |
| is foaf:primaryTopic of | wikipedia-en:BE_Ursae_Majoris |
