Universe Guide


1 Monocerotis, HD40535, HIP28321

1 Monocerotis is a blue to white pulsating subgiant star that can be located in the constellation of Monoceros. 1 Monocerotis is the brightest star in Monoceros based on the Hipparcos 2007 apparent magnitude. The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it.

HIP28321 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD40535.

1 Monocerotis has alternative name(s), V474 Mon.

Location of 1 Monocerotis

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 1 Monocerotis, the location is 05h 59m 01.07 and -09d22`56.1 .

Proper Motion of 1 Monocerotis

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 14.11 ± 0.25 miliarcseconds/year towards the north and 20.28 ± 0.45 miliarcseconds/year east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of 1 Monocerotis

1 Monocerotis has a spectral type of F2IV. This means the star is a blue to white subgiant star. The star is 7471.00000000 Parsecs from the Galactic Centre or terms of Light Years is 24367.6634302400000000s. The star has a B-V Colour Index of 0.33 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 7,066 Kelvin.

1 Monocerotis 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 2,471,886.85.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 3.32. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

1 Monocerotis Apparent and Absolute Magnitudes

1 Monocerotis has an apparent magnitude of 6.15 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 1.22 If you used the 2007 Parallax value, you would get an absolute magnitude of 1.37. 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 1 Monocerotis

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 10.32 which gave the calculated distance to 1 Monocerotis as 316.05 light years away from Earth or 96.90 parsecs. It would take a spaceship travelling at the speed of light, 316.05 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 11.07 which put 1 Monocerotis at a distance of 294.64 light years or 90.33 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 7,471.00 Parsecs or 24,367.66 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A*.

Variable Type of 1 Monocerotis

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. 1 Monocerotis brightness ranges from a magnitude of 6.335 to a magnitude of 6.075 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 0.1 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.

1 Monocerotis Facts

Alternative Names

Traditional/Proper Name1 Monocerotis
Flamsteed Name1 Monocerotis
Flamsteed Short Name1 Mon
Short NameV474 Mon
Hipparcos Library I.D.28321
Bonner DurchmusterungBD-09 1284
Henry Draper Designation40535

Visual Facts

Star Typesubgiant star
Absolute Magnitude1.22 / 1.37
Visual / Apparent Magnitude6.15
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)05h 59m 01.07
Declination (Dec.)-09d22`56.1
Galactic Latitude-15.87 degrees
Galactic Longitude215.50 degrees
1997 Distance from Earth10.32 Parallax (milliarcseconds)
 316.05 Light Years
 96.90 Parsecs
2007 Revised Distance from Earth11.07 Parallax (milliarcseconds)
 294.64 Light Years
 90.33 Parsecs
Galacto-Centric Distance24,367.66 Light Years / 7,471.00 Parsecs
Proper Motion Dec.14.11 ± 0.25 milliarcseconds/year
Proper Motion RA.20.28 ± 0.45 milliarcseconds/year
B-V Index0.33
Radial Velocity16.70 ± 1.20 km/s
Spectral TypeF2IV
Colour(F) blue to white

Variable Star Details

Variable Star ClassPulsating
Variable Star TypeDelta Scuti
Mean Variability Period in Days0.136
Variable Magnitude Range (Brighter - Dimmer)6.075 - 6.335

Estimated Facts

Calculated Effective Temperature7,066 Kelvin

Sources and Links

SIMBAD SourceLink

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