Tau Octantis Star Facts
Updated : 04/02/2025
Tau Octantis is agiant star located in the constellation ofOctans, The Octant.It is not part of the Octans constellation outline but is within the borders of the constellation.
Based on the spectral type (K2III), Tau Octantis colour isorange to red, these are stars that are cooler than our own star.
Tau Octantis temperature is in the range of between 3,700 and 5,200 Kelvin.Based on the spectral type (K2III) as we don't have the exact temperature', we can deduce that the surface temperature of Tau Octantis is in the order of 3,500 and 5,000K based on the notes fromHarvard University. To put this in context, the temperature of our Sun is about 5,778 Kelvin as said byGoogle.
Based on a parallax of 6.71, Tau Octantis distance from Earth can be calculated at being 486.09 light years away or 160.26 parsecs.
Tau Octantis is a naked-eye star, so you don't need a telescope or binoculars when you look up on a clear night. The lower the magnitude, the easier it will be to see it.
Location
Tau Octantis location in sky is determined by theright ascension (R.A.) and declination (Dec.). These are equivalent to the Longitude and Latitude on Earth.The Right Ascension (Longitude) is expressed in time (hh:mm:ss) and is how far the star is along Earth's celestial equator. If the R.A. is positive, then it's eastwards and vice versa.
The Declination (Latitude) is how far north or south the object is compared to the celestial equator and is expressed in degrees. If the value is positive, it is north of the celestial equator. ForTau Octantis, the location is 23h 28m 03.57 and -87° 28` 56.1 .
Based on the location of Octans, Tau Octantis can be located in the southern hemisphere of the celestial sky. The celestial hemisphere is equivalent to the hemispheres on Earth.Tau Octantis is south of the Ecliptic. The Ecliptic is the path that the Earth takes as it orbits the Sun. As the Earth is titled, we therefore have Celestial and Ecliptic hemispheres and they can be different for a star.
Physical Properties
Spectral Type
Tau Octantis spectral type of K2IIIwhich means its colour and type is orange to red giant star.There is no relationship between colour and size. For example, a red star can be large or small. Small stars are more energy efficient than larger stars and live longer.
Tau Octantis Luminosity
Luminosity is the amount of energy a star pumps out relative to the amount that our star, the Sun, gives out. Our star, the Sun's value is 1.Tau Octantis luminosity figure of 229.26 isbased on the value in the Simbad Hipparcos Extended Catalogue at the University of Strasbourg from 2012.The star generates more energy than our star.
Magnitude (Apparent / Absolute / Visible)
A number represents a star’s magnitude, whether apparent/visual or absolute. The smaller the number, the brighter the star is. The Sun is the brightest star and therefore has the lowest of all magnitudes, -26.74. A faint star will have a high number.
Tau Octantis apparent magnitude is 5.5, which is a measure of the star's brightness as seen from Earth. Apparent Magnitude is also known as Visual Magnitude.
If you use the 1997 parallax value, Tau Octantis' absolute magnitude is -0.52.If you use the 2007 parallax value, Tau Octantis' absolute magnitude is -0.37.Absolute Magnitude is the star's apparent magnitude from 10 parsecs or 32.6 light years. The magnitude assumes nothing is between the object and the viewer, such as dust clouds. To compare different stars' actual brightness, you would best use Absolute rather than Apparent Magnitude.
Tau Octantis is visible from Earth without needing binoculars or a telescope. The lower the Apparent Magnitude of a star or other object is, the easier it is to see in the night sky. An object with a magnitude greater than 6.5 cannot be seen without a telescope or other device.
Tau Octantis Distance from Earth
Tau Octantis distance from Earth is 522.70light-years away from Earth or 160.26parsecs. If you want that in miles, it is about 3,072,757,482,563,072.947, based on 1 Ly = 5,878,625,373,183.61 miles. The distance is calculated using the parallax from the original Hipparcos data released in 1997 which is 6.24000.
In 2007, Hipparcos data was revised with a new parallax of 6.71000, which puts the Tau Octantis distance from Earth as 486.09 light years or 149.03 parsecs. It should not be taken as though the star is moving closer or further away from Earth. It is purely that the distance was recalculated.
An Astronomical Unit is the distance between Earth and the Sun. The number of A.U. is the number of times that the star is from the Earth compared to the Sun. When you use the 2007 distance, Tau Octantis is roughly 30,739,429.88 Astronomical Units from the Earth/Sun give or take a few.
Tau Octantis Galacto-Centric Distance is 7,329 Parsecs or 23,904.511 Light Years. The Galacto-Centric Distance is the distance from the Tau Octantis to the Centre of the Galaxy which is Sagittarius A*.
How long it will take to get to Tau Octantis
The time it takes to travel to Tau Octantis depends on how fast you are going. U.G. has done some calculations as to how long it will take to go at differing speeds. A note about the calculations, when I'm talking about years, I'm talking about non-leap years only (365 days).
TheNew Horizons space probe is the fastest one that we've sent into space at the time of writing. Its primary mission was to visitPluto, which at the time of launch (2006), Pluto was still a planet.
Mach 1 is the speed of sound; Mach 2 is twice the speed. |Before retiring, Concorde was the fastest commercial aeroplane and the only passenger jet that could do Mach 2.
For some small screens, you may need to swipe the table to see the information. If you need an explanation, hover over the bold text. At methods are assuming you have unlimited fuel and travel at a constant speed.
- Walking - 81,495,009,297.653
- Car - 4,656,857,674.152
- Airbus A380 - 442,907,659.226
- Mach 1 - 424,857,562.59
- Mach 2 - 240,753,350.953
- New Horizons - 8,955,495.527
- Speed of Light - 486.09
Radial Velocity and Proper Motion
In simplistic terms, all non-rogue stars, like planets, orbit around a central object, although that is actually not true.Where is the centre of the Solar System. For simplicity it's the central star, such as the Sun. In the case of a star, it's the galactic centre. The constellations 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 is measured in milliarcseconds. Tau Octantis is moving 11.56± 0.17milliarcseconds/year towards the north and 16.83± 0.21milliarcseconds/year east if we saw them in the horizon.
Theradial velocity, the speed at which the Tau Octantis ismoving away fromthe Sun, is 31.00000 km/swith an error of about 1.40 km/s. When the value is negative, the star and the Sun are getting closer to one another; likewise, a positive number means that two stars are moving away. It's nothing to fear as the stars are so far apart they won't collide in our lifetime, if ever.
Source of Information
The source of the information if it has a Hip I.D. is fromSimbad, the Hipparcos data library based at the University at Strasbourg, France. Hipparcos was anE.S.A. satellite operation launched in 1989 for four years. The items in red are values that I've calculated, so they could be wrong.Information regarding Metallicity and/or Mass is from theE.U. Exoplanets. The data was obtained as of 12th Feb 2017.
Tau Octantis Fact List
The table is scrollable if you can't see everything, just swipe the table to see the hidden information.
Summary Facts
Primary Name:
Tau OctantisSpectral Type:
K2IIIStar Type:
Giant StarColour:
orange to redGalaxy:
Milky WayConstellation:
OctansCelestial Hemisphere:
SouthernMain Star
: YesVisual / Apparent Magnitude
: 5.5Visible From Earth
: YesAbsolute Magnitude
:-0.37Radial Velocity
: 31.00000 ± 1.4 km/sEccentricity:
0.1233Semi-Major Axis
: 6848Luminosity (Lsun)
: 229.26Location/Coordinates
Right Ascension
: 23h 28m 03.57Declination
: -87° 28` 56.1Galactic Latitude
: -29.47745216 °Galactic Longitude
: 303.96077143 °Galacto-Centric Distance:
23,904.511 Light Years / 7,329 Parsecs
Distance from Earth
Parallax
: 6.71000Light Years
: 486.09Parsecs
: 149.03Astronomical Units (A.U.)
: 30,739,429.88Proper Motion
: (milliarcseconds/year)Declination
: 11.56 ± 0.17Right Ascension
: 16.83 ± 0.21Miscellaneous Facts
B-V Index
: 1.27Alternate Names
:Tau Oct, HD 219765, TYC 9533-797-1, HIP 115836, HR 8862, Tau Oct
Sources and Links
- Modified Date: 4th February 2025
- Published Date: Jan 2015
- SIMBAD Source: Hipparcos Catalogue &Simbad
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