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ADS 9731 - HD139691 - HIP76563

ADS 9731 is a blue to white star that can be located in the constellation of CoronaBorealis. The star can not be seen by the naked eye, you need a telescope to see it. The star has an estimated age of 2.80 Billion of Years but could be as young as 2.50 to 3.10 according to Hipparcos.

HIP76563 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD139691.

Location of ADS 9731

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 ADS 9731, the location is 15h 38m 12.96 and +36d14`48.3 .

Proper Motion of ADS 9731

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 31.28 ± 4.31 miliarcseconds/year towards the north and -56.90 ± 5.48 miliarcseconds/year east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Age, Radius) of ADS 9731

ADS 9731 has a spectral type of F5. This means the star is a blue to white star. The star has a B-V Colour Index of 1.7 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 3,456 Kelvin.

ADS 9731 Radius has been calculated as being 8.78 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 6,112,476.37.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 11.06. 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 -0.14 with an error value of 0.08 Fe/H with the Sun has a value of 1 to put it into context.

The stars age according to Hipparcos data files put the star at an age of about 2.80 Billion years old but could be between 2.50 and 3.10 Billion years old. In comparison, the Sun's age is about 4.6 Billion Years Old.

ADS 9731 Apparent and Absolute Magnitudes

ADS 9731 has an apparent magnitude of 7.07 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 2.36 If you used the 2007 Parallax value, you would get an absolute magnitude of 1.86. 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 ADS 9731

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 11.42 which gave the calculated distance to ADS 9731 as 285.61 light years away from Earth or 87.57 parsecs. It would take a spaceship travelling at the speed of light, 285.61 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 9.07 which put ADS 9731 at a distance of 359.61 light years or 110.25 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.

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.

ADS 9731 Facts

Alternative Names

Traditional/Proper NameADS 9731
Hipparcos Library I.D.76563
Bonner DurchmusterungBDD+36 2626
Henry Draper Designation139691

Visual Facts

Star Type star
Age2.80 Billion Years Old
Age Range2.50 - 3.10 Billion Years Old
Absolute Magnitude2.36 / 1.86
Visual / Apparent Magnitude7.07
Naked Eye VisibleRequires a 7x50 Binoculars - Ref: Wiki
Right Ascension (R.A.)15h 38m 12.96
Declination (Dec.)+36d14`48.3
Galactic Latitude53.66 degrees
Galactic Longitude58.06 degrees
1997 Distance from Earth11.42 Parallax (milliarcseconds)
 285.61 Light Years
 87.57 Parsecs
2007 Revised Distance from Earth9.07 Parallax (milliarcseconds)
 359.61 Light Years
 110.25 Parsecs
Proper Motion Dec.31.28 ± 4.31 milliarcseconds/year
Proper Motion RA.-56.90 ± 5.48 milliarcseconds/year
B-V Index1.70
Radial Velocity-34.35 ± 0.10 km/s
Iron Abundance-0.14 ± 0.08 Fe/H
Spectral TypeF5
Colour(F) blue to white

Estimated Facts

Calculated Effective Temperature3,456 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars

Multi-Star System

The star has been identified as being a multi-star system, one in which there is at least one star in close orbit to another star or two or more stars orbiting a central point. The stars may be of equal mass, unequal mass where one star is stronger than the other or be in groups orbiting a central point which doesn't necessarily have to be a star. More information can be found on my dedicated multiple star systems page. The source of the info is Simbad. The file is dated 2000 so any differences between this and any other source will be down to the actual source from where the information came from.


Proper Motion mas/yr
H.D. IdB.D. IdStar CodeMagnitudeR.A.Dec.SpectrumColourYear
139691+36 2626.0A7.00000-59.0000049.00000F5Yellow/White
B12.100001905

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