Star in the constellation Hydrus
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! style="text-align: center; background-color: #FFFFC0;" colspan="2" | Observation dataEpoch J2000      Equinox J2000
! style="text-align:left" | Constellation
! style="text-align:left" | Right ascension
! style="text-align:left" | Declination
! style="text-align:left" | Apparent magnitude (V)
! style="background-color: #FFFFC0; text-align: center;" colspan="2"| Characteristics
! style="text-align:left" | Spectral type
! style="text-align:left" | U−B 
! style="text-align:left" | B−V 
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Delta Hydri, Latinized from δ Hydri, is a single, white-hued star in the southern constellation of Hydrus. It is bright enough to be faintly visible to the naked eye with an apparent visual magnitude of 4.09. The distance to this star, based upon an annual parallax shift of 23.35 mas, is about 140 light years. It is moving away from the Sun with a radial velocity of +6 km/s.
This is an ordinary A-type main-sequence star with a stellar classification of A2 V It is about 209 million years old and has a high rate of spin, showing a projected rotational velocity of 162 km/s. This is giving the star an oblate shape with an equatorial bulge that is 7% larger than the polar radius. The star has 2.25 times the mass of the Sun and 2.3 times the Sun's radius. It is radiating 39.5 times the Sun's luminosity from its photosphere at an effective temperature of around 9.880. Delta Hydri has been checked for an infrared excess, but none was found.
References.
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