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B Octantis, HD206553, HIP112355

B Octantis is a blue pulsating star that can be located in the constellation of Octans. The star can not be seen by the naked eye, you need a telescope to see it.

HIP112355 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD206553.

B Octantis has alternative name(s), CG Oct.

Location of B Octantis

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 B Octantis, the location is 22h 45m 29.59 and -88d 49` 05.5 .

Proper Motion of B Octantis

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 -35.73 ± 0.25 miliarcseconds/year towards the north and 22.42 ± 0.32 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 14.90000 km/s with an error of about 1.90 km/s .

Physical Properties (Colour, Temperature, Radius) of B Octantis

B Octantis has a spectral type of A7IV. This means the star is a blue star. The star is 7350.00000000 Parsecs from the Galactic Centre or terms of Light Years is 23973.0057840000000000s. The star has a B-V Colour Index of 0.29 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 7,270 Kelvin.

B Octantis Radius has been calculated as being 2.88 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 2,005,874.66.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 2.96. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

B Octantis Apparent and Absolute Magnitudes

B Octantis has an apparent magnitude of 6.55 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 1.55 If you used the 2007 Parallax value, you would get an absolute magnitude of 1.49. 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 B Octantis

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 9.99 which gave the calculated distance to B Octantis as 326.49 light years away from Earth or 100.10 parsecs. It would take a spaceship travelling at the speed of light, 326.49 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 9.73 which put B Octantis at a distance of 335.21 light years or 102.77 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 7,350.00 Parsecs or 23,973.01 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A*.

Variable Type of B Octantis

The star is a pulsating Delta Scuti variable type which means that its size changes over time. The Variable Type is usually named after the first star of that type to be spotted. B Octantis brightness ranges from a magnitude of 6.643 to a magnitude of 6.619 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 0.1 days (variability).

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.

B Octantis Facts

Alternative Names

Traditional/Proper NameB Octantis
Short NameCG Oct
Hipparcos Library I.D.112355
Henry Draper Designation206553

Visual Facts

Star Type star
Absolute Magnitude1.55 / 1.49
Visual / Apparent Magnitude6.55
Naked Eye VisibleRequires a 7x50 Binoculars - Magnitudes
Right Ascension (R.A.)22h 45m 29.59
Declination (Dec.)-88d 49` 05.5
Galactic Latitude-28.13 degrees
Galactic Longitude303.63 degrees
1997 Distance from Earth9.99 Parallax (milliarcseconds)
 326.49 Light Years
 100.10 Parsecs
2007 Revised Distance from Earth9.73 Parallax (milliarcseconds)
 335.21 Light Years
 102.77 Parsecs
Galacto-Centric Distance23,973.01 Light Years / 7,350.00 Parsecs
Proper Motion Dec.-35.73 ± 0.25 milliarcseconds/year
Proper Motion RA.22.42 ± 0.32 milliarcseconds/year
B-V Index0.29
Radial Velocity14.90 ± 1.90 km/s
Spectral TypeA7IV
Colour(A) blue

Variable Star Details

Variable Star ClassPulsating
Variable Star TypeDelta Scuti
Mean Variability Period in Days0.122
Variable Magnitude Range (Brighter - Dimmer)6.619 - 6.643

Estimated Facts

Calculated Effective Temperature7,270 Kelvin

Sources and Links

SIMBAD SourceLink

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