Universe Guide


V745 Cassiopeiae, HD1810, HIP1805

V745 Cassiopeiae is a blue eclipsing binary system subgiant star that can be located in the constellation of Cassiopeia. The star can not be seen by the naked eye, you need a telescope to see it.

HIP1805 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD1810.

V745 Cassiopeiae has alternative name(s), V745 Cas.

Location of V745 Cassiopeiae

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 V745 Cassiopeiae, the location is 00h 22m 53.34 and +62d14`29.0 .

Proper Motion of V745 Cassiopeiae

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 -1.57 ± 0.62 miliarcseconds/year towards the north and -3.70 ± 0.92 miliarcseconds/year east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of V745 Cassiopeiae

V745 Cassiopeiae has a spectral type of B0IV. This means the star is a blue subgiant star. The star has a B-V Colour Index of 0 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 9,531 Kelvin.

V745 Cassiopeiae Radius has been calculated as being 3.55 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 2,472,359.82.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 3.00. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

V745 Cassiopeiae Apparent and Absolute Magnitudes

V745 Cassiopeiae has an apparent magnitude of 8.17 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 -0.08 If you used the 2007 Parallax value, you would get an absolute magnitude of 0.29. 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 V745 Cassiopeiae

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 2.24 which gave the calculated distance to V745 Cassiopeiae as 1456.09 light years away from Earth or 446.43 parsecs. It would take a spaceship travelling at the speed of light, 1456.09 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 2.66 which put V745 Cassiopeiae at a distance of 1226.18 light years or 375.94 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 V745 Cassiopeiae

The star is a eclipsing binary system W Ursae Majoris 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. V745 Cassiopeiae brightness ranges from a magnitude of 8.164 to a magnitude of 8.063 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 1.4 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.

V745 Cassiopeiae Facts

Alternative Names

Traditional/Proper NameV745 Cassiopeiae
Short NameV745 Cas
Hipparcos Library I.D.1805
Bonner DurchmusterungBD+61 50
Henry Draper Designation1810

Visual Facts

Star Typesubgiant star
Absolute Magnitude-0.08 / 0.29
Visual / Apparent Magnitude8.17
Naked Eye VisibleRequires a 7x50 Binoculars - Magnitudes
Right Ascension (R.A.)00h 22m 53.34
Declination (Dec.)+62d14`29.0
Galactic Latitude-0.45 degrees
Galactic Longitude119.61 degrees
1997 Distance from Earth2.24 Parallax (milliarcseconds)
 1456.09 Light Years
 446.43 Parsecs
2007 Revised Distance from Earth2.66 Parallax (milliarcseconds)
 1226.18 Light Years
 375.94 Parsecs
Proper Motion Dec.-1.57 ± 0.62 milliarcseconds/year
Proper Motion RA.-3.70 ± 0.92 milliarcseconds/year
B-V Index0.00
Radial Velocity-52.00 ± 7.40 km/s
Spectral TypeB0IV
Colour(B) blue

Variable Star Details

Variable Star ClassEclipsing binary system
Variable Star TypeW Ursae Majoris
Mean Variability Period in Days1.411
Variable Magnitude Range (Brighter - Dimmer)8.063 - 8.164

Estimated Facts

Calculated Effective Temperature9,531 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars

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
1810+61 50.0A8.40000-1.000007.00000B3Blue/White

Add a Comment

Email: (Optional)