Universe Guide


41 Herculis, HD151090, HIP81991

41 Herculis is a white to yellow star that can be located in the constellation of Hercules. The star can not be seen by the naked eye, you need a telescope to see it.

HIP81991 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD151090. The Id of the star in the Gould Star Catalogue is 14. 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 41 Herculis

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 41 Herculis, the location is 16h 45m 00.11 and +06d05`19.6 .

Proper Motion of 41 Herculis

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 -257.77 ± 0.34 miliarcseconds/year towards the north and -213.49 ± 0.61 miliarcseconds/year east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of 41 Herculis

41 Herculis has a spectral type of G5. This means the star is a white to yellow star. The star is 7364.00000000 Parsecs from the Galactic Centre or terms of Light Years is 24018.6686521600000000s. The star has a B-V Colour Index of 0.89 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 5,217 Kelvin.

41 Herculis Radius has been calculated as being 2.65 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 1,847,204.74.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 2.57. 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 -0.19 with an error value of 0.04 Fe/H with the Sun has a value of 1 to put it into context.

41 Herculis Apparent and Absolute Magnitudes

41 Herculis 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 3.17 If you used the 2007 Parallax value, you would get an absolute magnitude of 3.24. 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 41 Herculis

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 21.06 which gave the calculated distance to 41 Herculis as 154.87 light years away from Earth or 47.48 parsecs. It would take a spaceship travelling at the speed of light, 154.87 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 21.80 which put 41 Herculis at a distance of 149.62 light years or 45.87 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 7,364.00 Parsecs or 24,018.67 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.

41 Herculis Facts

Alternative Names

Traditional/Proper Name41 Herculis
Flamsteed Name41 Herculis
Flamsteed Short Name41 Her
Hipparcos Library I.D.81991
Bonner DurchmusterungBD+06 3288
Gould I.D.14
Henry Draper Designation151090

Visual Facts

Star Type star
Absolute Magnitude3.17 / 3.24
Visual / Apparent Magnitude6.55
Naked Eye VisibleRequires a 7x50 Binoculars - Magnitudes
Right Ascension (R.A.)16h 45m 00.11
Declination (Dec.)+06d05`19.6
Galactic Latitude30.81 degrees
Galactic Longitude23.33 degrees
1997 Distance from Earth21.06 Parallax (milliarcseconds)
 154.87 Light Years
 47.48 Parsecs
2007 Revised Distance from Earth21.80 Parallax (milliarcseconds)
 149.62 Light Years
 45.87 Parsecs
Galacto-Centric Distance24,018.67 Light Years / 7,364.00 Parsecs
Proper Motion Dec.-257.77 ± 0.34 milliarcseconds/year
Proper Motion RA.-213.49 ± 0.61 milliarcseconds/year
B-V Index0.89
Radial Velocity-7.08 ± 0.11 km/s
Iron Abundance-0.19 ± 0.04 Fe/H
Spectral TypeG5
Colour(G) White to Yellow

Estimated Facts

Calculated Effective Temperature5,217 Kelvin

Sources and Links

SIMBAD SourceLink

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