Universe Guide


84 Ceti - HD16765 - HIP12530

84 Ceti is a blue to white subgiant star that can be located in the constellation of Cetus. HIP12530 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD16765. The Id of the star in the Gould Star Catalogue is 288. Stars in the southern hemisphere are more likely to have a Gould Id than the northern hemisphere. For example, there are no Gould classified stars in Ursa Major. 84 Ceti has alternative name(s), 84 Ceti , 84 Cet. 84 Ceti is a multiple star system with 2 stars orbiting in its solar system.

Location of 84 Ceti

The location of the star in the galaxy is determined by the Right Ascension (R.A.) and Declination (Dec.), these are equivalent to the Longitude and Latitude on the Earth. The Right Ascension is how far expressed in time (hh:mm:ss) the star is along the celestial equator. If the R.A. is positive then its eastwards. The Declination is how far north or south the star is compared to the celestial equator and is expressed in degrees. For 84 Ceti, the location is 02h 41m 13.87 and -00d41`43.3 .

Proper Motion of 84 Ceti

All stars like planets orbit round a central spot, in the case of planets, its the central star such as the Sun. In the case of a star, its the galactic centre. The constellations that we see today will be different than they were 50,000 years ago or 50,000 years from now. Proper Motion details the movements of these stars and are measured in milliarcseconds. The star is moving -129.33 ± 000.76 towards the north and 216.51 ± 000.84 east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of 84 Ceti

84 Ceti has a spectral type of F7IV. This means the star is a blue to white subgiant star. The star has a B-V Colour Index of 0.51 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 6,243 Kelvin.

84 Ceti has been calculated as 1.24 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 864,095.01.km.

84 Ceti Apparent and Absolute Magnitudes

84 Ceti has an apparent magnitude of 5.72 which is how bright we see the star from Earth. Apparent Magnitude is also known as Visual Magnitude. If you used the 1997 Parallax value, you would get an absolute magnitude of 4.04 If you used the 2007 Parallax value, you would get an absolute magnitude of 3.95. Magnitude, whether it be apparent/visual or absolute magnitude is measured by a number, the smaller the number, the brighter the Star is. Our own Sun is the brightest star and therefore has the lowest of all magnitudes, -26.74. A faint star will have a high number.

Distance to 84 Ceti

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 46.24 which gave the calculated distance to 84 Ceti as 70.54 light years away from Earth or 21.63 parsecs. It would take a spaceship travelling at the speed of light, 70.54 years to get there. We don't have the technology or spaceship that can carry people over that distance yet.

In 2007, Hipparcos data was revised with a new parallax of 44.27 which put 84 Ceti at a distance of 73.68 light years or 22.59 parsecs. It should not be taken as though the star is moving closer or further away from us. It is purely that the distance was recalculated.

Source of Information

The source of the information if it has a Hip I.D. is from Simbad, the Hipparcos data library based at the University at Strasbourg, France. Hipparcos was a E.S.A. satellite operation launched in 1989 for four years. The items in red are values that I've calculated so they could well be wrong. Information regarding Stellar Age, Metallicity or Mass is from the E.U. Exoplanets. The information was obtained as of 12th Feb 2017.

84 Ceti Facts

Alternative Names

Traditional Name84 Ceti
Short Name84 Cet
Alternative Name(s)84 Ceti
Hipparcos Library I.D.12530
Bonner DurchmusterungBD-01 377
Gould I.D.288
Henry Draper Designation16765

Visual Facts

Star Typesubgiant star
Absolute Magnitude4.04 / 3.95
Apparent Magnitude5.72
Right Ascension (R.A.)02h 41m 13.87
Declination (Dec.)-00d41`43.3
1997 Distance from Earth46.24 Parallax (milliarcseconds)
 70.54 Light Years
 21.63 Parsecs
2007 Revised Distance from Earth44.27 Parallax (milliarcseconds)
 73.68 Light Years
 22.59 Parsecs
Proper Motion Dec.-129.33 ± 0.76 milliarcseconds/year
Proper Motion RA.216.51 ± 0.84 milliarcseconds/year
B-V Index0.51
Spectral TypeF7IV
Colour(F) blue to white
Stars in Solar System2

Estimated Facts

Radius (x the Sun)1.24
Calculated Effective Temperature6,243 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars

Multi-Star System

The star has been identified as being a multi-star system, one in which there is at least one star in close orbit to another star or two or more stars orbiting a central point. The stars may be of equal mass, unequal mass where one star is stronger than the other or be in groups orbiting a central point which doesn't necessarily have to be a star. More information can be found on my dedicated multiple star systems page. The source of the info is Simbad. The file is dated 2000 so any differences between this and any other source will be down to the actual source from where the information came from.

Proper Motion mas/yr
H.D. IdB.D. IdStar CodeMagnitudeR.A.Dec.SpectrumColourYear
16765-01 377.0A5.80000222.00000-144.00000F5Yellow/White

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