Hadar (Beta Centauri) Star Facts

Hadar, also known as Beta Centauri is a giant star located in the constellation of Centaurus, The Centaur. Hadar is a major star and forms part of the constellation. Hadar is the traditional/proper name for the star, whilst Beta Centauri is the Bayer Designation for the star. A list of additional names and identifications is in the facts list at the bottom of the page.

Based on the spectral type (B1III), Hadar colour is blue, which means that the star is one of the hottest stars in the Universe, hotter than our star.

Hadar temperature is in the range of 10,000 to 30,000 Kelvin. Based on the spectral type (B1III) as we don't have the exact temperature', we can deduce that the surface temperature of Hadar is in the order of 10,000 and 25,000K based on the notes from Harvard University. To put this in context, the temperature of our Sun is about 5,778 Kelvin as said by Google.

Hadar is the 11th brightest star in the night sky and the 2nd brightest star in Centaurus based on the Hipparcos 2007 apparent magnitude. Based on a parallax of 8.32, Hadar distance from Earth can be calculated at being 392.02 light years away or 161.03 parsecs.

Hadar 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.

Hadar is a beta cephei variable star. Variable stars are stars whose size and/or brightness changes over time. Hadar brightness ranges from 0.556 (dimmest) to 0.516 over a period of 0.03 days.

Location

The location of the Hadar in the night sky is determined by the right 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. For Hadar, the location is 14h 03m 49.44 and -60° 22` 22.7 .

Based on the location of Centaurus, Hadar can be located in the southern hemisphere of the celestial sky. The celestial hemisphere is equivalent to the hemispheres on Earth. Hadar 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.

Map


Physical Properties

Hadar 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. Hadar luminosity figure of 45,273.9 is based on the value in the Simbad Hipparcos Extended Catalogue at the University of Strasbourg from 2012. The star generates more energy than our star.

Hadar Size (Radius)

Hadar radius has been calculated as being 9 times bigger than the Sun. The Sun's radius is 695,800km, therefore, the Hadar radius is an estimated 6,262,200.km. If you need the star's diameter, you just need to multiply the radius by 2.

Hadar Mass

Hadar mass is 12.02 times that of our star, the Sun. There is an uncertainty of between -0.130 and +0.1300. 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 an idea of size, the Sun is 99.86% of the solar system's mass.

Hadar Death

We can't be sure when Hadar will die, we can have estimations based on its spectral type and mass. Based on current estimations with Hadar being more than 10 solar masses, it will at the end of its life, most likely die in a Supernova explosion. The explosion will leave behind either a Pulsar or a Black Hole.

Hadar Age

Hadar age according to Hipparcos data files put the star at an age of about 0.014 billion years old but could be between -0.586 and 0.614 billion years old. In comparison, the Sun's age is about 4.6 billion years old. The smaller star is, the more efficient it is with its fuel and so will live longer than a star which is very large. Hadar lifespan can be measured in millions of years based on a typical blue star (B Type). B stars are short lived stars as they are not fuel-efficient.

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.

Hadar apparent magnitude is 0.61, 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, Hadar' absolute magnitude is -5.42. If you use the 2007 parallax value, Hadar' absolute magnitude is -4.79. 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.

Hadar 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.

Meteor Showers

There are 1 meteor showers that radiate from a location near Hadar during the year.


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. Hadar is moving -23.16 ± 0.34 milliarcseconds/year towards the north and -33.27 ± 0.5 milliarcseconds/year east if we saw them in the horizon.

The radial velocity, the speed at which the Hadar is moving away from the Sun, is 5.90000 km/s with an error of about 3.80 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 from Simbad, the Hipparcos data library based at the University at Strasbourg, France. Hipparcos was an E.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 the E.U. Exoplanets. The data was obtained as of 12th Feb 2017.

Hadar Fact List

The table is scrollable if you can't see everything, just swipe the table to see the hidden information.

Key Facts

Primary Name:

Hadar

Spectral Type:

B1III

Star Type:

Giant Star

Colour:

blue

Galaxy:

Milky Way

Constellation:

Centaurus

Celestial Hemisphere:

Southern

Main Star

: Yes

Age

: 14 million years

Age Range

: -0.586 - 0.614 billion years

Visual / Apparent Magnitude

: 0.61

Visible From Earth

: Yes

Absolute Magnitude

: -4.79

Radial Velocity

: 5.90000 ± 3.8 km/s

Eccentricity:

0.05570

Semi-Major Axis

: 6949.0000000

Luminosity (Lsun)

: 45273.9000000

Mass (Solars)

: 12.0200 (-0.130 / +0.1300)

Radius

: 9

Location/Coordinates

Right Ascension

: 14h 03m 49.44

Declination

: -60° 22` 22.7

Galactic Latitude

: 1.25113883 °

Galactic Longitude

: 311.76704914 °

Galacto-Centric Distance:

23,878.418 Light Years / 7,321 Parsecs

Distance from Earth


Parallax

: 8.32000

Light Years

: 392.02

Parsecs

: 120.19

Astronomical Units (A.U.)

: 24,790,794.318

Proper Motion

: (milliarcseconds/year)

Declination

: -23.16000 ± 0.34000

Right Ascension

: -33.27000 ± 0.50000

Miscellaneous Facts

B-V Index

: -0.23

Brightest in Night Sky

: 11th

Variable Star Class

: Pulsating

Variable Star Type

: Beta Cephei

Mean Variability Period (Days)

: 0.03

Variable Magnitude Range

: 0.516 - 0.556

Alternate Names

: Beta Centauri, Bet Cen, Beta CenTau, Agena, Hadar, HD 122451, TYC 9005-3919-1, HIP 68702, HR 5267, 304 G. Centauri, bet Cen

Sources and Links

  • Modified Date: 21st April 2024
  • Published Date: Jan 2015
  • SIMBAD Source: Hipparcos Catalogue & Simbad
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Centaurus's Main Stars in Brightness Order



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