(Redirected from Delta-1 Tauri)The
Bayer designation 'Delta Tauri' (δ Tau / δ Tauri) is shared by three star systems in the
constellation Taurus. They are all members of the
Hyades star cluster.
Because they are close to the
ecliptic, these stars can be
occulted by the
Moon and very rarely by
planets. The last occultation of δ¹ Tauri by a planet took place on
3 January,
1818, when it was occulted by
Venus.
δ¹ Tauri
'δ¹ Tauri' is a
triple star approximately 153
light years from
Earth and has the traditional name 'Hyadum II', which is
Latin for "Second Hyad", and the name '''Eudora''' (
Greek Ευδωρη), who was one of the Hyades sisters.
The primary component, 'Delta-1 Tauri A', is an orange
K-type giant with an
apparent magnitude of +3.77. Delta-1 has a
luminosity of 74 times that of the
Sun and a radius of 11.6 times solar. Its mass is calculated to be 2.6
solar masses. The surface temperature of this star is 4965
kelvins. Its companion, 'Delta-1 Tauri B', is a 12th magnitude star separated by 107
arcseconds from the primary. It is most likely not physically related to the main star. However, observations of lunar
occultations of this star has revealed a much closer, physically related, star that orbits the main star in an
eccentric orbit with an average distance of 1.76
AU. This companion takes about 530 days to orbit the main star.
δ² Tauri
'δ² Tauri' is a white
A-type main sequence dwarf with an
apparent magnitude of +4.80. It is approximately 146
light years from
Earth and is separated from δ¹ Tauri by 0.23° on the sky.
δ³ Tauri
'δ³ Tauri' is a
triple star system in the
constellation Taurus. It is approximately 148
light years from
Earth and is separated from δ¹ Tauri by 0.72° on the sky. This star also has the traditional name 'Cleeia' or '''Kleeia''' (
Greek Κλεεια), who was one of the Hyades sisters.
The primary component, 'δ³ Tauri A', is a white
A-type subgiant with a mean
apparent magnitude of +4.30. It is classified as an
Alpha2 Canum Venaticorum type variable star and its brightness varies from magnitude +4.29 to +4.32 with a period of 57.25 days. It has a close, 8th magnitude binary companion, 'δ³ Tauri B', 1.4
arcseconds, or at least 64
Astronomical Units, away. At 77
arcseconds away is the third component, the 11th magnitude 'δ³ Tauri C'.
References
★
HD 27697 -- Spectroscopic binary
★
HD 27819 -- Star in double system
★
HD 27962 -- Variable Star
External links
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Delta-1 Tau
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Star Names