Universe Guide

AH Draconis

AH Draconis Facts

AH Draconis's Alternative Names

HIP82249 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD152152.

AH Draconis has alternative name(s) :- AH Dra, AH Dra.

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+58 1672.

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

Location of AH Draconis

The location of the variable 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 object is compared to the celestial equator and is expressed in degrees. For AH Draconis, the location is 16h 48m 16.64 and +57° 48` 49.4 .

Radial Velocity and Proper Motion of AH Draconis

Proper Motion

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 0.03 ± 0.61 milliarcseconds/year towards the north and -10.10 ± 0.72 milliarcseconds/year east if we saw them in the horizon.

Radial Velocity

The Radial Velocity, that is the speed at which the star is moving away/towards the Sun is 57.44 km/s with an error of about 0.58 km/s . 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.

Physical Properties (Colour, Temperature) of AH Draconis

AH Draconis Colour and Temperature

AH Draconis has a spectral type of M7. This means the star is a red variable star. The star has a B-V Colour Index of 1.32 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 4,351 Kelvin.

AH Draconis Radius

Radius has been calculated as being 15.69 times bigger than the Sun. The Sun's radius is 695,800km, therefore the star's radius is an estimated 10,919,649.08.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 20.78. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

AH Draconis Apparent and Absolute Magnitudes

AH Draconis has an apparent magnitude of 7.45 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 0.10 If you used the 2007 Parallax value, you would get an absolute magnitude of -0.51. 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 AH Draconis

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 3.39 which gave the calculated distance to AH Draconis as 962.13 light years away from Earth or 294.99 parsecs. If you want that in miles, it is 7,489,839,015,465,761.09.

In 2007, Hipparcos data was revised with a new parallax of 2.56 which put AH Draconis at a distance of 1274.08 light years or 390.62 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 80,570,597.19 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.

Time to Travel to AH Draconis

A note about the calculations, when I'm talking about years, I'm talking non-leap years only (365 days).

If you were to drive there at about 120 m.p.h. in a car with an infinity engine so you didn't have to pull over for petrol, it would take you 47,133,348,585,842.81 hours or 5,380,519,244.96 years.

At the time of writing, the fastest probe so far created is the New Horizon probe which is travelling at a speed of 33,000 m.p.h. If the probe was travelling to AH Draconis then it would take 171,393,994,857.61 hours / 19,565,524.53 years to get there. Speed Ref: N.A.S.A.

It would to take a spaceship journey travelling at the speed of light, 962.13 years to get there. We don't have the technology or spaceship that can carry people over that distance yet.

Variable Type of AH Draconis

The star is a pulsating Semiregular late- (M variable type which means that its size changes over time. The Variable Type is usually named after the first star of that type to be spotted. AH Draconis brightness ranges from a magnitude of 7.523 to a magnitude of 6.563 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 188.4 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.

Hide Explanations
Show GridLines

Additional AH Draconis Facts and Figures

Visual Facts

Primary / Proper / Traditional NameAH Draconis
Alternative NamesAH Dra, HD 152152, HIP 82249, BD+58 1672, AH Dra
Spectral TypeM7
Constellation's Main StarNo
Multiple Star SystemNo / Unknown
Star TypeVariable Star
GalaxyMilky Way
Absolute Magnitude 0.10 / -0.51
Visual / Apparent Magnitude7.45
Naked Eye VisibleRequires a 7x50 Binoculars - Magnitudes
Right Ascension (R.A.)16h 48m 16.64
Declination (Dec.)+57° 48` 49.4
Galactic Latitude38.95 degrees
Galactic Longitude86.89 degrees
1997 Distance from Earth3.39 Parallax (milliarcseconds)
 962.13 Light Years
 294.99 Parsecs
2007 Distance from Earth2.56 Parallax (milliarcseconds)
 1274.08 Light Years
 390.62 Parsecs
 80,570,597.19 Astronomical Units
Proper Motion Dec.0.03 ± 0.61 milliarcseconds/year
Proper Motion RA.-10.10 ± 0.72 milliarcseconds/year
B-V Index1.32
Radial Velocity57.44 ± 0.58 km/s

Companions (Multi-Star and Exoplanets) Facts

Exoplanet CountNone/Unaware

Variable Star Details

Variable Star ClassPulsating
Variable Star TypeSemiregular late- (M
Mean Variability Period in Days188.400
Variable Magnitude Range (Brighter - Dimmer)6.563 - 7.523

Estimated Calculated Facts

Radius (x the Sun)20.78
Effective Temperature4,351 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars

Comments and Questions

There's no register feature and no need to give an email address if you don't need to. All messages will be reviewed before being displayed. Comments may be merged or altered slightly such as if an email address is given in the main body of the comment.

You can decline to give a name which if that is the case, the comment will be attributed to a random star. A name is preferred even if its a random made up one by yourself.

This website is using cookies. More info. That's Fine