Universe Guide

BN Puppis

BN Puppis Facts

  • BN Puppis is a pulsating variable star that can be located in the constellation of Puppis. The description is based on the spectral class.
  • BN Puppis is not part of the constellation outline but is within the borders of the constellation.
  • Based on the spectral type (G4) 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.
  • Using the most recent figures given by the 2007 Hipparcos data, the star is 862.87 light years away from us. Distance

BN Puppis's Alternative Names

HIP39666 is the reference name for the star in the Hipparcos Star Catalogue.

BN Puppis has alternative name(s) :- BN Pup, BN Pup.

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

Location of BN Puppis

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 BN Puppis, the location is 08h 06m 21.48 and -30° 05` 48.8 .

Radial Velocity and Proper Motion of BN Puppis

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 0.31 ± 1.13 milliarcseconds/year towards the north and -0.69 ± 1.59 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 65.40000 km/s with an error of about 0.90 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 BN Puppis

BN Puppis Temperature and Colour

Based on the star's spectral type of G4 , BN Puppis's colour and type is yellow variable star. The star has a B-V Colour Index of 1.23 which means the star's temperature is about 4,512 Kelvin. The temperature was calculated using information from Morgans @ Uni.edu.

BN Puppis Radius

BN Puppis estimated radius has been calculated as being 3.16 times bigger than the Sun. The Sun's radius is 695,800km, therefore the star's radius is an estimated 2,200,979.88.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 4.0750885248525557058712150416. 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.

BN Puppis Apparent and Absolute Magnitudes

BN Puppis has an apparent magnitude of 9.98 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 3.42 If you used the 2007 Parallax value, you would get an absolute magnitude of 2.87. 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 BN Puppis

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 4.88000 which gave the calculated distance to BN Puppis as 668.37 light years away from Earth or 204.92 parsecs. If you want that in miles, it is about 3,929,096,840,674,729.42, based on 1 Ly = 5,878,625,373,183.61 miles.

In 2007, Hipparcos data was revised with a new parallax of 3.78000 which put BN Puppis at a distance of 862.87 light years or 264.55 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 54,566,974.26 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.

Travel Time to BN Puppis

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 A380736786,215,992.75
Speed of Sound (Mach 1)767.269754,174,833.94
Concorde (Mach 2)1,534.54377,086,925.51
New Horizons Probe33,00017,534,999.11
Speed of Light670,616,629.00862.87

Variable Type of BN Puppis

The star is a pulsating Delta Cepheid 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. BN Puppis brightness ranges from a magnitude of 10.634 to a magnitude of 9.282 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 13.7 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.

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Additional BN Puppis Facts and Figures

Visual Facts

Primary / Proper / Traditional NameBN Puppis
Alternative NamesBN Pup, HIP 39666, BN Pup
Spectral TypeG4
Constellation's Main StarNo
Multiple Star SystemYes
Star TypeVariable Star
GalaxyMilky Way
Absolute Magnitude 3.42 / 2.87
Visual / Apparent Magnitude9.98
Naked Eye VisibleRequires a 7x50 Binoculars - Magnitudes
Right Ascension (R.A.)08h 06m 21.48
Declination (Dec.)-30° 05` 48.8
Galactic Latitude1.06542903 degrees
Galactic Longitude247.89690292 degrees
1997 Distance from Earth4.88000 Parallax (milliarcseconds)
 668.37 Light Years
 204.92 Parsecs
2007 Distance from Earth3.78000 Parallax (milliarcseconds)
 862.87 Light Years
 264.55 Parsecs
 54,566,974.26 Astronomical Units
Proper Motion Dec.0.31000 ± 1.13000 milliarcseconds/year
Proper Motion RA.-0.69000 ± 1.59000 milliarcseconds/year
B-V Index1.23
Radial Velocity65.40000 ± 0.90 km/s

Companions (Multi-Star and Exoplanets) Facts

Exoplanet CountNone/Unaware

Variable Star Details

Variable Star ClassPulsating
Variable Star TypeDelta Cepheid
Mean Variability Period in Days13.673
Variable Magnitude Range (Brighter - Dimmer)9.282 - 10.634

Estimated Calculated Facts

Radius (x the Sun)4.08
Effective Temperature4,512 Kelvin

Sources and Links

SIMBAD SourceLink

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
-29 5535.2A10.10000G4Yellow

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