Zeta Delphini (ΞΆ Delphini) is a
star
A star is an astronomical object comprising a luminous spheroid of plasma (physics), plasma held together by its gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked ...
in the
constellation
A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object.
The origins of the e ...
of
Delphinus. With an apparent magnitude of about 4.6,
[ it is faintly visible to the naked eye. ]Parallax
Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight and is measured by the angle or semi-angle of inclination between those two lines. Due to foreshortening, nearby objects ...
measurements of the system made by the Hipparcos
''Hipparcos'' was a scientific satellite of the European Space Agency (ESA), launched in 1989 and operated until 1993. It was the first space experiment devoted to precision astrometry, the accurate measurement of the positions of celestial obj ...
spacecraft put it at a distance of about 220 light-year
A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 1012 ...
s, or 67 parsecs.[
Zeta Delphini has a spectral type of A3V, implying it is an ]A-type main-sequence star
An A-type main-sequence star (A V) or A dwarf star is a main-sequence (hydrogen-burning) star of spectral type A and luminosity class V (five). These stars have spectra defined by strong hydrogen Balmer absorption lines. They measure between 1 ...
.[ These types of stars are bluish-white colored, and have ]effective temperature
The effective temperature of a body such as a star or planet is the temperature of a black body that would emit the same total amount of electromagnetic radiation. Effective temperature is often used as an estimate of a body's surface temperature ...
s between 7100 and 11500 K:[ Its age is estimated to be around 500 million years, considerably younger than the Sun.][
In 2014, the discovery of a brown dwarf around Zeta Delphini was announced. Zeta Delphini B is a brown dwarf with a spectral type of L5 (but may be from L3 to L7), and has a mass of about 55 Jupiters. At over 13 ]arcsecond
A minute of arc, arcminute (arcmin), arc minute, or minute arc, denoted by the symbol , is a unit of angular measurement equal to of one degree. Since one degree is of a turn (or complete rotation), one minute of arc is of a turn. The na ...
s away, this brown dwarf is separated at least 910 AU from Zeta Delphini.[
]
References
External links
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{{DEFAULTSORT:Zeta Delphini
Delphinus (constellation)
A-type main-sequence stars
Delphini, Zeta
101589
Delphini, 04
Brown dwarfs
196180
7871
Durchmusterung objects
L-type stars