Universe Guide


Pi Ceti, 89 Ceti, HD17081, HIP12770

Pi Ceti is a blue subgiant star that can be located in the constellation of Cetus. Pi Ceti is the brightest star in Cetus based on the Hipparcos 2007 apparent magnitude. The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it.

Pi Ceti is the Bayer Classification for the star. HIP12770 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD17081. The Id of the star in the Gould Star Catalogue is 296. 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.

Location of Pi 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 Pi Ceti, the location is 02h 44m 07.35 and -13d51`31.2 .

Proper Motion of Pi 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 -9.07 ± 0.15 miliarcseconds/year towards the north and -8.62 ± 0.21 miliarcseconds/year east if we saw them in the horizon.

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

Pi Ceti has a spectral type of B7IV. This means the star is a blue subgiant star. The star is 7459.00000000 Parsecs from the Galactic Centre or terms of Light Years is 24328.5238289600000000s. The star has a B-V Colour Index of -0.12 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 12,367 Kelvin.

Pi Ceti Radius has been calculated as being 3.89 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 2,709,398.91.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 3.47. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures. The star's Iron Abundance is 0.24 with an error value of 0.04 Fe/H with the Sun has a value of 1 to put it into context.

Pi Ceti Apparent and Absolute Magnitudes

Pi Ceti has an apparent magnitude of 4.24 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 -1.41 If you used the 2007 Parallax value, you would get an absolute magnitude of -1.16. 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 Pi Ceti

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 7.40 which gave the calculated distance to Pi Ceti as 440.76 light years away from Earth or 135.14 parsecs. It would take a spaceship travelling at the speed of light, 440.76 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 8.30 which put Pi Ceti at a distance of 392.97 light years or 120.48 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 7,459.00 Parsecs or 24,328.52 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A*.

Meteor Showers Radiating from near Pi Ceti

The Pi Cetids Meteor Shower radiants from a point near this star. The meteor shower runs typically between 16 Jun- 4 Jul with a peak date of 26-Jun. The speed of a meteor in the shower is 67 Km/s. The amount of meteors predicted to be seen per hour (Zenith Hourly Rate) is 67.

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.

Pi Ceti Facts

Alternative Names

Flamsteed Name89 Ceti
Flamsteed Short Name89 Cet
Bayer DesignationPi Ceti
Hipparcos Library I.D.12770
Bonner DurchmusterungBD-14 519
Gould I.D.296
Henry Draper Designation17081

Visual Facts

Star Typesubgiant star
Absolute Magnitude-1.41 / -1.16
Visual / Apparent Magnitude4.24
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)02h 44m 07.35
Declination (Dec.)-13d51`31.2
Galactic Latitude-60.57 degrees
Galactic Longitude191.81 degrees
1997 Distance from Earth7.40 Parallax (milliarcseconds)
 440.76 Light Years
 135.14 Parsecs
2007 Revised Distance from Earth8.30 Parallax (milliarcseconds)
 392.97 Light Years
 120.48 Parsecs
Galacto-Centric Distance24,328.52 Light Years / 7,459.00 Parsecs
Proper Motion Dec.-9.07 ± 0.15 milliarcseconds/year
Proper Motion RA.-8.62 ± 0.21 milliarcseconds/year
B-V Index-0.12
Radial Velocity14.98 ± 0.25 km/s
Iron Abundance0.24 ± 0.04 Fe/H
Spectral TypeB7IV
Colour(B) blue

Estimated Facts

Calculated Effective Temperature12,367 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars

Location of Pi Ceti in Cetus

Pi Ceti (Pi Ceti) Location in Cetus

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

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