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V388 Cephei - HD219586 - HIP114831

V388 Cephei is a blue to white pulsating subgiant star that can be located in the constellation of Cepheus. HIP114831 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD219586. V388 Cephei has alternative name(s), V388_Cep.

Location of V388 Cephei

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 V388 Cephei, the location is 23h 15m 37.71 and +70d53`17.1 .

Proper Motion of V388 Cephei

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 -001.70 ± 000.32 towards the north and 017.72 ± 000.41 east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of V388 Cephei

V388 Cephei has a spectral type of F0IV. This means the star is a blue to white subgiant star. The star has a B-V Colour Index of 0.26 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 7,428 Kelvin.

V388 Cephei has been calculated as 4.78 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 3,323,843.03.km.

V388 Cephei Apparent and Absolute Magnitudes

V388 Cephei has an apparent magnitude of 5.55 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 0.36 If you used the 2007 Parallax value, you would get an absolute magnitude of 0.22. 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 V388 Cephei

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 9.15 which gave the calculated distance to V388 Cephei as 356.46 light years away from Earth or 109.29 parsecs. It would take a spaceship travelling at the speed of light, 356.46 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 8.60 which put V388 Cephei at a distance of 379.26 light years or 116.28 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.

Variable Type of V388 Cephei

The star is a pulsating Delta Scuti 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. V388 Cephei brightness ranges from a magnitude of 6.000 to a magnitude of 6.000 over its variable period. The smaller the magnitude, the brighter the star.

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 Stellar Age, Metallicity or Mass is from the E.U. Exoplanets. The information was obtained as of 12th Feb 2017.

V388 Cephei Facts

Alternative Names

Traditional NameV388 Cephei
Short NameV388 Cep
Hipparcos Library I.D.114831
Bonner DurchmusterungBD+70 1311
Henry Draper Designation219586

Visual Facts

Star Typesubgiant star
Absolute Magnitude0.36 / 0.22
Apparent Magnitude5.55
Right Ascension (R.A.)23h 15m 37.71
Declination (Dec.)+70d53`17.1
1997 Distance from Earth9.15 Parallax (milliarcseconds)
 356.46 Light Years
 109.29 Parsecs
2007 Revised Distance from Earth8.60 Parallax (milliarcseconds)
 379.26 Light Years
 116.28 Parsecs
Proper Motion Dec.-1.70 ± 0.32 milliarcseconds/year
Proper Motion RA.17.72 ± 0.41 milliarcseconds/year
B-V Index0.26
Spectral TypeF0IV
Colour(F) blue to white

Variable Star Details

Variable Star ClassPulsating
Variable Star TypeDelta Scuti

Estimated Facts

Radius (x the Sun)4.78
Calculated Effective Temperature7,428 Kelvin

Sources and Links

SIMBAD SourceLink

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