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V990 Herculis, HD169888, HIP90338

Primary Facts on V990 Herculis

  • V990 Herculis's star type is variable star that can be located in the constellation of Hercules. The description is based on the spectral class.
  • V990 Herculis is not part of the constellation outline but is within the borders of the constellation.
  • Based on the spectral type (A0) of the star, the star's colour is blue .
  • The star can not be seen by the naked eye, you need a telescope to see it.
  • Using the most recent figures given by the 2007 Hipparcos data, the star is 680.93 light years away from us.

V990 Herculis's Alternative Names

HIP90338 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD169888.

V990 Herculis has alternative name(s) :- , V990 Her.

BD number is the number that the star was filed under in the Durchmusterung or Bonner Durchmusterung, a star catalogue that was put together by the Bonn Observatory between 1859 to 1903. The star's BD Number is BD+21 3427.

More details on star alternative names can be found at Star Names .

Location of V990 Herculis

The location of the star in the night sky 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 V990 Herculis, the location is 18h 25m 56.71 and +21° 36` 21.2 .

Proper Motion of V990 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 21.69 ± 0.41 miliarcseconds/year towards the north and -0.12 ± 0.64 miliarcseconds/year east if we saw them in the horizon. . When the value is negative then the star and the Sun are getting closer to one another, likewise, a positive number means that two stars are moving away. Its nothing to fear as the stars are so far apart, they won't collide in our life-time, if ever.

V990 Herculis Luminosity

Luminosity is the amount of energy that a star pumps out and its relative to the amount that our star, the Sun gives out. The figure of 29.36 that I have given is based on the value in the Simbad Hipparcos Extended Catalogue at the University of Strasbourg from 2012.

Physical Properties (Colour, Temperature) of V990 Herculis

V990 Herculis has a spectral type of A0. This means the star is a blue variable star. The star is 7,275.00 Parsecs from the Galactic Centre or in terms of Light Years is 23,728.38 s. The star has a B-V Colour Index of 0.22 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 7,253 Kelvin.

V990 Herculis Radius has been calculated as being 4.38 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 3,050,324.86.km. If you need the diameter of the star, you just need to multiple the radius by 2. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 3.60. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

V990 Herculis Apparent and Absolute Magnitudes

V990 Herculis has an apparent magnitude of 7.68 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 0.65 If you used the 2007 Parallax value, you would get an absolute magnitude of 1.08. 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 V990 Herculis

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 3.93 which gave the calculated distance to V990 Herculis as 829.93 light years away from Earth or 254.45 parsecs. It would take a spaceship travelling at the speed of light, 829.93 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 4.79 which put V990 Herculis at a distance of 680.93 light years or 208.77 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.

Using the 2007 distance, the star is roughly 43,061,603.54 Astronomical Units from the Earth/Sun give or take a few. 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.

The star's Galacto-Centric Distance is 7,275.00 Parsecs or 23,728.38 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A*. V990 Herculis brightness ranges from a magnitude of 7.775 to a magnitude of 7.722 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 0.2 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.

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Additional V990 Herculis Facts and Figures

Visual Facts


Primary / Proper / Traditional NameV990 Herculis
Alternative NamesHD 169888, HIP 90338, BD+21 3427, V990 Her
Spectral TypeA0
Constellation's Main StarNo
Multiple Star SystemNo / Unknown
Star TypeVariable Star
Colour blue
GalaxyMilky Way
ConstellationHercules
Absolute Magnitude 0.65 / 1.08
Visual / Apparent Magnitude7.68
Naked Eye VisibleRequires a 7x50 Binoculars - Magnitudes
Right Ascension (R.A.)18h 25m 56.71
Declination (Dec.)+21° 36` 21.2
Galactic Latitude15.06 degrees
Galactic Longitude49.83 degrees
1997 Distance from Earth3.93 Parallax (milliarcseconds)
 829.93 Light Years
 254.45 Parsecs
2007 Distance from Earth4.79 Parallax (milliarcseconds)
 680.93 Light Years
 208.77 Parsecs
 43,061,603.54 Astronomical Units
Galacto-Centric Distance23,728.38 Light Years / 7,275.00 Parsecs
Proper Motion Dec.21.69 ± 0.41 milliarcseconds/year
Proper Motion RA.-0.12 ± 0.64 milliarcseconds/year
B-V Index0.22
Stellar Luminosity (Lsun)29.36

Companions (Multi-Star and Exoplanets) Facts


Exoplanet CountNone/Unaware

Variable Star Details


Mean Variability Period in Days0.164
Variable Magnitude Range (Brighter - Dimmer)7.722 - 7.775

Estimated Facts


Calculated Effective Temperature7,253 Kelvin

Sources and Links


SIMBAD SourceLink

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