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Deneb Algenub, Eta Ceti, 31 Ceti, HD6805, HIP5364, HR334

Deneb Algenub (Eta Ceti) is a orange to red star that can be located in the constellation of Cetus. The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it.

Eta Ceti is the Bayer Classification for the star. The Id of the star in the Yale Bright Star Catalogue is HR334. HIP5364 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD6805. The Id of the star in the Gould Star Catalogue is 111. 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.

Deneb Algenub has alternative name(s), Algenudi , Eta Ceti.

Location of Deneb Algenub

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 Deneb Algenub, the location is 01h 08m 35.26 and -10d 10` 54.9 .

Proper Motion of Deneb Algenub

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 -139.02 ± 0.09 miliarcseconds/year towards the north and 215.61 ± 0.14 miliarcseconds/year east if we saw them in the horizon. The Radial Velocity, that is the speed at which the star is moving away/towards us is 11.40000 km/s with an error of about 0.80 km/s .

Deneb Algenub Luminosity

Luminosity is the amount of energy that a star pumps out and its relative to the amount that our star, the Sun gives out. The figure of 70.0000000 that I have given is based on the Spectral Types page that I have found on the Internet. You might find a different figure, one that may have been calculated rather than generalised that I have done. The figure is always the amount times the luminosity of the Sun. It is an imprecise figure because of a number of factors including but not limited to whether the star is a variable star and distance.

Physical Properties (Colour, Temperature, Metallicity, Mass, Radius) of Deneb Algenub

Deneb Algenub has a spectral type of K2III. This means the star is a orange to red star. The star is 7408.00000000 Parsecs from the Galactic Centre or terms of Light Years is 24162.1805235200000000s. The star has a B-V Colour Index of 1.1 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 4,664 Kelvin.

Deneb Algenub Radius has been calculated as being 10.50 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 7,309,104.46.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 11.05. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures. The star's solar mass is 1.70 times that of the Sun's. The Sun's Mass is 1,989,100,000,000,000,000,000 billion kg. which to calculate using this website is too large. To give idea of size, the Sun is 99.86% the mass of the solar system.

The star's metallicity is 0.120000, this value is the fractional amount of the star that is not Hydrogen (X) or Helium (Y). An older star would have a high metallicity whereas a new star would have a lower one.

Deneb Algenub Apparent and Absolute Magnitudes

Deneb Algenub has an apparent magnitude of 3.46 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 0.67 If you used the 2007 Parallax value, you would get an absolute magnitude of 0.56. 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 Deneb Algenub

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 27.73 which gave the calculated distance to Deneb Algenub as 117.62 light years away from Earth or 36.06 parsecs. It would take a spaceship travelling at the speed of light, 117.62 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 26.32 which put Deneb Algenub at a distance of 123.92 light years or 37.99 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.

The star's Galacto-Centric Distance is 7,408.00 Parsecs or 24,162.18 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A*.

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 Metallicity and/or Mass is from the E.U. Exoplanets. The information was obtained as of 12th Feb 2017.

Deneb Algenub Facts

Alternative Names

Traditional/Proper NameDeneb Algenub
Flamsteed Name31 Ceti
Flamsteed Short Name31 Cet
Short NameEta Ceti
Bayer DesignationEta Ceti
Alternative Name(s)Algenudi
Hipparcos Library I.D.5364
Yale Bright Star Catalogue (HR) Id334
Bonner DurchmusterungBD-10 240
Gould I.D.111
Henry Draper Designation6805

Visual Facts

Star Type star
Absolute Magnitude0.67 / 0.56
Visual / Apparent Magnitude3.46
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)01h 08m 35.26
Declination (Dec.)-10d 10` 54.9
Galactic Latitude-72.58 degrees
Galactic Longitude137.16 degrees
1997 Distance from Earth27.73 Parallax (milliarcseconds)
 117.62 Light Years
 36.06 Parsecs
2007 Revised Distance from Earth26.32 Parallax (milliarcseconds)
 123.92 Light Years
 37.99 Parsecs
Galacto-Centric Distance24,162.18 Light Years / 7,408.00 Parsecs
Proper Motion Dec.-139.02 ± 0.09 milliarcseconds/year
Proper Motion RA.215.61 ± 0.14 milliarcseconds/year
B-V Index1.10
Radial Velocity11.40 ± 0.80 km/s
Iron Abundance0.09 ± 0.02 Fe/H
Spectral TypeK2III
Colour(K) Orange to Red

Estimated Facts

Luminosity (x the Sun)70.0000000
Calculated Effective Temperature4,664 Kelvin
Mass Compared to the Sun1.70

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
6805-10 240.0A3.60000214.00000-133.00000K0Orange
-10 239.0B10.300001907

Location of Deneb Algenub in Cetus

Deneb Algenub (Eta Ceti) Location in Cetus

The map was generated using Night Vision, an awesome free application by Brian Simpson.

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