Universe Guide

HD 189733

HD 189733 Facts

  • HD 189733 is a star that can be located in the constellation of Vulpecula. The description is based on the spectral class.
  • HD 189733 is not part of the constellation outline but is within the borders of the constellation.
  • Based on the spectral type (G5) of the star, the star's colour is yellow .
  • The star can not be seen by the naked eye, you need a telescope to see it.
  • HD 189733 has at least 1 Extrasolar Planets believed to be in orbit around the star.
  • Using the most recent figures given by the 2007 Hipparcos data, the star is 63.44 light years away from us. Distance

Information on HD 189733

You might think that the planet is a nice friendly environment on which to visit on account of it being blue like our planet is blue. The colour hides the fact the moment you get down to the planet, you will be shredded to bits by the rain. The rain and winds blow up to 5,400 MPH, (2 km/s). The planet zips around its star at an astonishing speed, completing the journey in 2.2. days. The rain is probably class so would cut you to smithereens. If there happened to any intelligent life on the planet, you should not pick a fight with them. For them to survive on the planet, their skins would be made of steel or stronger and you would loose. Ref: N.A.S.A.

HD 189733's Alternative Names

HIP98505 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD189733.

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+22 3887.

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

Location of HD 189733

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 object is compared to the celestial equator and is expressed in degrees. For HD 189733, the location is 20h 00m 43.71 and +22° 42` 41.3 .

Radial Velocity and Proper Motion of HD 189733

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 -251.40 ± 0.39 milliarcseconds/year towards the north and -2.14 ± 0.69 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 -2.55000 km/s with an error of about 0.21 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 of HD 189733

HD 189733 Colour and Temperature

Based on the star's spectral type of G5 , HD 189733's colour and type is yellow star. The star has a B-V Colour Index of 0.93 which means the star's temperature is about 5,127 Kelvin. The temperature was calculated using information from Morgans @ Uni.edu.

HD 189733 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 0.37 that I have given is based on the value in the Simbad Hipparcos Extended Catalogue at the University of Strasbourg from 2012.

HD 189733 Radius

HD 189733 estimated radius has been calculated as being 0.67 times bigger than the Sun. The Sun's radius is 695,800km, therefore the star's radius is an estimated 463,020.09.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 0.6716076087715677854318587055. The figure is derived at by using the formula from SDSS rather than peer reviewed papers. It has been known to produce widely incorrect figures.

HD 189733 Iron Abundance

HD 189733 Iron Abundance is -0.02 with an error value of 9.99 Fe/H with the Sun has a value of 1 to put it into context. The value comes from the Hipparcos Extended Catalog.

HD 189733 Apparent and Absolute Magnitudes

HD 189733 has an apparent magnitude of 7.67 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 6.25 If you used the 2007 Parallax value, you would get an absolute magnitude of 6.23. 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 HD 189733

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 51.94000 which gave the calculated distance to HD 189733 as 62.80 light years away from Earth or 19.25 parsecs. If you want that in miles, it is about 369,177,673,435,930.71, based on 1 Ly = 5,878,625,373,183.61 miles.

In 2007, Hipparcos data was revised with a new parallax of 51.41000 which put HD 189733 at a distance of 63.44 light years or 19.45 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 4,011,822.53 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 7,391.00 Parsecs or 24,106.73 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A*.

Travel Time to HD 189733

The time it will take to travel to this star is dependent on how fast you are going. U.G. has done some calculations as to how long it will take going at differing speeds. A note about the calculations, when I'm talking about years, I'm talking non-leap years only (365 days).

The New Horizons space probe is the fastest probe that we've sent into space at the time of writing. Its primary mission was to visit Pluto which at the time of launch (2006), Pluto was still a planet.

DescriptionSpeed (m.p.h.)Time (years)
Airbus A38073657,804,237.70
Speed of Sound (Mach 1)767.26955,448,504.95
Concorde (Mach 2)1,534.5427,724,216.34
New Horizons Probe33,0001,289,209.66
Speed of Light670,616,629.0063.44

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 HD 189733 Facts and Figures

Visual Facts

Primary / Proper / Traditional NameHD 189733
Alternative NamesHD 189733, HIP 98505, BD+22 3887
Spectral TypeG5
Constellation's Main StarNo
Multiple Star SystemNo / Unknown
Star TypeStar
GalaxyMilky Way
Absolute Magnitude 6.25 / 6.23
Visual / Apparent Magnitude7.67
Naked Eye VisibleRequires a 7x50 Binoculars - Magnitudes
Right Ascension (R.A.)20h 00m 43.71
Declination (Dec.)+22° 42` 41.3
Galactic Latitude-3.92195511 degrees
Galactic Longitude60.96358234 degrees
1997 Distance from Earth51.94000 Parallax (milliarcseconds)
 62.80 Light Years
 19.25 Parsecs
2007 Distance from Earth51.41000 Parallax (milliarcseconds)
 63.44 Light Years
 19.45 Parsecs
 4,011,822.53 Astronomical Units
Galacto-Centric Distance24,106.73 Light Years / 7,391.00 Parsecs
Proper Motion Dec.-251.40000 ± 0.39000 milliarcseconds/year
Proper Motion RA.-2.14000 ± 0.69000 milliarcseconds/year
B-V Index0.93
Radial Velocity-2.55000 ± 0.21 km/s
Iron Abundance-0.0200 ± 9.99 Fe/H
Semi-Major Axis7611.0000000
Stellar Luminosity (Lsun)0.3700000

Companions (Multi-Star and Exoplanets) Facts

Exoplanet Count1

Estimated Calculated Facts

Radius (x the Sun)0.67
Effective Temperature5,127 Kelvin

Sources and Links

SIMBAD SourceLink

List of Extrasolar Planets orbiting HD 189733

NameStatusMass (Jupiters)Orbital Period (Days)EccentricityDiscoveredSemi-Major AxisPeriastronInclination
HD 189733 bConfirmed0.0252.2190.004120050.0314290.00085.510

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