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HD 165155, HIP88650

HD 165155 is a white to yellow main sequence dwarf star that can be located in the constellation of Sagittarius. The star can not be seen by the naked eye, you need a telescope to see it. It is calculated at being 11.000 Billion Years old. This information comes from ExoPlanet.

HIP88650 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD165155. HD 165155 has at least 1 Extrasolar Planets believed to be in orbit around the star.

Location of HD 165155

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 HD 165155, the location is 18h 05m 57.30 and -29d55`02.1 .

Proper Motion of HD 165155

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 -3.71 ± 0.96 miliarcseconds/year towards the north and 73.74 ± 1.72 miliarcseconds/year east if we saw them in the horizon.

HD 165155 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 1.0000000 that I have given is based on the Spectral Types page that I have found on the Internet. You might find a different figure, one that may have been calculated rather than generalised that I have done. The figure is always the amount times the luminosity of the Sun. It is an imprecise figure because of a number of factors including but not limited to whether the star is a variable star and distance.

Physical Properties (Colour, Temperature, Metallicity, Age, Mass, Radius) of HD 165155

HD 165155 has a spectral type of G8V. This means the star is a white to yellow main sequence dwarf star. The star is 7336.00000000 Parsecs from the Galactic Centre or terms of Light Years is 23927.3429158400000000s. The star has a B-V Colour Index of 1.01 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 4,830 Kelvin.

HD 165155 Radius has been calculated as being 1.12 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 778,826.55.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 1.16. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures. The star's solar mass is 1.02 times that of the Sun's. The Sun's Mass is 1,989,100,000,000,000,000,000 billion kg. which to calculate using this website is too large. To give idea of size, the Sun is 99.86% the mass of the solar system.

The star's metallicity is 0.090000, this value is the fractional amount of the star that is not Hydrogen (X) or Helium (Y). An older star would have a high metallicity whereas a new star would have a lower one.

The star is believed to be about 11.00 Billion years old. To put in context, the Sun is believed to be about five billion years old and the Universe is about 13.8 billion years old.

HD 165155 Apparent and Absolute Magnitudes

HD 165155 has an apparent magnitude of 9.36 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 5.38 If you used the 2007 Parallax value, you would get an absolute magnitude of 5.30. 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 165155

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 16.01 which gave the calculated distance to HD 165155 as 203.72 light years away from Earth or 62.46 parsecs. It would take a spaceship travelling at the speed of light, 203.72 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 15.39 which put HD 165155 at a distance of 211.93 light years or 64.98 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.

The star's Galacto-Centric Distance is 7,336.00 Parsecs or 23,927.34 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A*.

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.

HD 165155 Facts

Alternative Names

Traditional/Proper NameHD 165155
Hipparcos Library I.D.88650
Henry Draper Designation165155

Visual Facts

Star Typemain sequence dwarf star
Age11.00 Billion Years Old
Metalicity0.0900
Absolute Magnitude5.38 / 5.30
Visual / Apparent Magnitude9.36
Naked Eye VisibleRequires a 7x50 Binoculars - Magnitudes
Right Ascension (R.A.)18h 05m 57.30
Declination (Dec.)-29d55`02.1
Galactic Latitude-4.32 degrees
Galactic Longitude1.38 degrees
1997 Distance from Earth16.01 Parallax (milliarcseconds)
 203.72 Light Years
 62.46 Parsecs
2007 Revised Distance from Earth15.39 Parallax (milliarcseconds)
 211.93 Light Years
 64.98 Parsecs
Galacto-Centric Distance23,927.34 Light Years / 7,336.00 Parsecs
Proper Motion Dec.-3.71 ± 0.96 milliarcseconds/year
Proper Motion RA.73.74 ± 1.72 milliarcseconds/year
B-V Index1.01
Radial Velocity14.90 ± 0.40 km/s
Iron Abundance0.24 ± 0.08 Fe/H
Spectral TypeG8V
Colour(G) White to Yellow

Companions (Multi-Star and Exoplanets) Facts

Exoplanet Count1

Estimated Facts

Luminosity (x the Sun)1.0000000
Calculated Effective Temperature4,830 Kelvin
Mass Compared to the Sun1.02
Metallicity0.09000

Sources and Links

SIMBAD SourceLink

Related Stars


List of Extrasolar Planets orbiting HD 165155


NameStatusMass (Jupiters)Orbital Period (Days)EccentricityDiscoveredSemi-Major AxisPeriastron
Hd 165155 BConfirmed2.89434.5000.220161.13211.000

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