Universe Guide

BF Sagittae (Carbon Star) Facts

BF Sagittae Facts

  • BF Sagittae is a pulsating Carbon star that can be located in the constellation of Sagitta. The description is based on the spectral class.
  • BF Sagittae is not part of the constellation outline but is within the borders of the constellation.
  • Based on the spectral type (C5II) of the star, the star's colour is carbon red .
  • 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 2470.93 light years away from us. Distance

BF Sagittae's Alternative Names

HIP98662 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD190048.

BF Sagittae has alternative name(s) :- , BF Sge.

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+20 4390.

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

Location of BF Sagittae

The location of the Carbon 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 BF Sagittae, the location is 20h 02m 23.08 and +21° 05` 24.9 .

Radial Velocity and Proper Motion of BF Sagittae

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 -5.43 ± 0.67 milliarcseconds/year towards the north and -1.17 ± 1.09 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 -14.00000 km/s with an error of about 3.20 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 BF Sagittae

BF Sagittae Colour and Temperature

Based on the star's spectral type of C5II , BF Sagittae's colour and type is carbon red Carbon star. The star has a B-V Colour Index of 1.6 which means the star's temperature is about 3,775 Kelvin. The temperature was calculated using information from Morgans @ Uni.edu.

BF Sagittae Apparent and Absolute Magnitudes

BF Sagittae has an apparent magnitude of 9.14 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 If you used the 2007 Parallax value, you would get an absolute magnitude of -0.26. 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 BF Sagittae

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as -0.01000 which gave the calculated distance to BF Sagittae as -326163.34 light years away from Earth or -100000 parsecs. If you want that in miles, it is about -1,917,392,086,326,312,670.86, based on 1 Ly = 5,878,625,373,183.61 miles.

In 2007, Hipparcos data was revised with a new parallax of 1.32000 which put BF Sagittae at a distance of 2470.93 light years or 757.58 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 156,261,003.07 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 BF Sagittae

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 A3807362,251,422,210.73
Speed of Sound (Mach 1)767.2692,159,668,573.99
Concorde (Mach 2)1,534.541,079,832,879.62
New Horizons Probe33,00050,213,537.79
Speed of Light670,616,629.002,470.93

Variable Type of BF Sagittae

The star is a pulsating Slow Irregular 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. BF Sagittae brightness ranges from a magnitude of 9.370 to a magnitude of 9.110 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 0.2 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 BF Sagittae Facts and Figures

Visual Facts

Primary / Proper / Traditional NameBF Sagittae
Alternative NamesHD 190048, HIP 98662, BD+20 4390, BF Sge
Spectral TypeC5II
Constellation's Main StarNo
Multiple Star SystemYes
Star TypeCarbon Star
GalaxyMilky Way
Absolute Magnitude / -0.26
Visual / Apparent Magnitude9.14
Naked Eye VisibleRequires a 7x50 Binoculars - Magnitudes
Right Ascension (R.A.)20h 02m 23.08
Declination (Dec.)+21° 05` 24.9
Galactic Latitude-5.09956641 degrees
Galactic Longitude59.78128779 degrees
1997 Distance from Earth-0.01000 Parallax (milliarcseconds)
 -326163.34 Light Years
 -100000 Parsecs
2007 Distance from Earth1.32000 Parallax (milliarcseconds)
 2470.93 Light Years
 757.58 Parsecs
 156,261,003.07 Astronomical Units
Proper Motion Dec.-5.43000 ± 0.67000 milliarcseconds/year
Proper Motion RA.-1.17000 ± 1.09000 milliarcseconds/year
B-V Index1.6
Radial Velocity-14.00000 ± 3.20 km/s

Companions (Multi-Star and Exoplanets) Facts

Exoplanet CountNone/Unaware

Variable Star Details

Variable Star ClassPulsating
Variable Star TypeSlow Irregular
Mean Variability Period in Days0.211
Variable Magnitude Range (Brighter - Dimmer)9.110 - 9.370

Estimated Calculated Facts

Effective Temperature3,775 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
190048+20 4390.0A9.90000-1.00000-6.00000CI

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