HIP 99439 is a star that can be located in the constellation of Cygnus. The description is based on the spectral class. HIP 99439 is not part of the constellation but is within the borders of the constellation.
HIP99439 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD191978.
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+40 4050.
More details on star alternative names can be found at Star Names .
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 -4.79 ± 0.59 miliarcseconds/year towards the north and -5.29 ± 0.61 miliarcseconds/year east if we saw them in the horizon.
The Radial Velocity, that is the speed at which the star is moving away/towards the Sun is -17.50 km/s with an error of about 1.40 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.
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.
|Primary / Proper / Traditional Name||HIP 99439|
|Alternative Names||HD 191978, HIP 99439, BD+40 4050|
|Constellation's Main Star||No|
|Multiple Star System||No / Unknown|
|Galactic Latitude||4.25 degrees|
|Galactic Longitude||77.87 degrees|
|Distance from Earth||0.01 Parallax (milliarcseconds)|
|326163.34 Light Years|
|20,626,336,898.40 Astronomical Units|
|Proper Motion Dec.||-4.79 ± 0.59 milliarcseconds/year|
|Proper Motion RA.||-5.29 ± 0.61 milliarcseconds/year|
|Radial Velocity||-17.50 ± 1.40 km/s|