24 Ursae Majoris Star Facts (Distance, Age, Mass, Colour & more)

24 Ursae Majoris is a Subgiant Star that is located in the constellation of Ursa Major. Based on the spectral type (G4III-IV) of the star, the 24 Ursae Majoris colour is yellow . It is not part of the Ursa Major constellation outline but is within the borders of the constellation.

The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it.

24 Ursae Majoris is located in the Milky Way galaxy, this is the galaxy that you reside in. In case you're wondering, 24 Ursae Majoris is not located within the Solar System, there is only one star in the Solar System and that is the Sun.

There are no known exoplanets in orbit round the star, there might or might not be any but due to their size compared to the star, they'll be very hard to spot compared to other smaller stars hence why none have been spotted around a supergiant.

No one has visited 24 Ursae Majoris and we have no probes on a rendezvous with the star.

It is calculated at being 4.604 Billion Years old. This information comes from ExoPlanet.

Using the most recent figures given by the 2007 Hipparcos data, 24 Ursae Majoris distance from Earth is 104.14 light years. When you look at 24 Ursae Majoris, you are in fact looking back in time, you are seeing how it looks years ago. Roughly, change the distance from light years to years, that will tell you how long ago we are looking at the star.

24 Ursae Majoris Location

The location of the subgiant 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 24 Ursae Majoris, the location is 09h 34m 28.97 and +69° 49` 48.6 .

24 Ursae Majoris Radial Velocity and Proper Motion

24 Ursae Majoris 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 77.25 ± 0.13 milliarcseconds/year towards the north and -63.84 ± 0.19 milliarcseconds/year east if we saw them in the horizon.

24 Ursae Majoris Radial Velocity

The Radial Velocity, that is the speed at which the star is towards the Sun is -27.00000 km/s with an error of about 0.20 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.

24 Ursae Majoris Physical Properties

24 Ursae Majoris Colour

Based on the star's spectral type of G4III-IV , 24 Ursae Majoris's colour and type is yellow subgiant star.

There is no relationship between colour and size, a red star can be both the largest and the smallest stars in the Universe. Small stars are more energy efficient than larger stars and live longer.

24 Ursae Majoris Temperature

Based on the spectral type as we don't have the exact temperature', we can deduce that the surface temperature of the star is in the order of 5,000 and 6,000K based on the notes from Harvard University. To put this in context, the temperature of our Sun is about 5,778 Kelvin as said by Google.

• Blue (O) > 25,000K
• Blue/White (B) = 10,000 - 25,000K
• Blue/White (A) = 7,500 - 10,000K
• Yellow/White (F) = 6,000 - 7,500K
• Yellow (G) = 5,000 - 6,000K
• Orange/Red (K) = 3,500 - 5000K
• Red (M) = < 3,500K
• Red (C) = < 3,500K

There is a relationship between colour and temperature, stars that are closer to red in the rainbow spectrum are cooler whereas those closer to blue are hotter. Those that are blue stars are normally identified as being young stars whereas redder stars are usually older stars, ones that are at the end of their life. An example of when its a Blue Straggler, the star has stolen matter from a nearby star and grown to appear youthful when its not. These stars are found mainly in Star Clusters.

24 Ursae Majoris Luminosity

Luminosity is the amount of energy that a star pumps out and its relative to the amount that our star, the Sun gives out. Our star, the Sun's value is 1. ' The figure of 15.77 that I have given is based on the value in the Simbad Hipparcos Extended Catalogue at the University of Strasbourg from 2012. The star generates more energy than our star.

24 Ursae Majoris Radius

24 Ursae Majoris estimated radius has been calculated as being 4.368 times bigger than the Sun. The Sun's radius is 695,800km, therefore the star's radius is an estimated 3,039,302.223.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 4.308. 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.

24 Ursae Majoris Mass

The 24 Ursae Majoris's solar mass is 1.234 times that of our star, the Sun. The Sun's Mass is 1,989,100,000,000,000,000,000 billion kg. which to calculate using this website is too large. To give idea of size, the Sun is 99.86% the mass of the solar system.

24 Ursae Majoris Metallicity

The star's metallicity is -0.250000, this value is the fractional amount of the star that is not Hydrogen (X) or Helium (Y). An older star would have a high metallicity whereas a new star would have a lower one.

24 Ursae Majoris Age

24 Ursae Majoris is believed to be about 4.604 Billion years old. To put in context, the Sun is believed to be about five billion years old and the Universe is about 13.8 billion years old.

24 Ursae Majoris Apparent (Brightness) and Absolute Magnitudes

Absolute Magnitude is the apparent magnitude of the star from a distance of 10 parsecs or 32.6 light years. This assumes that there is nothing in between the object and the viewer such as dust clouds. To really compare the brightness of the star, it is best to use Absolute rather than Apparent Magnitude.

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.

24 Ursae Majoris apparent magnitude is 4.54, this is a measure of the brightness of the star as seen from Earth. Apparent Magnitude is also known as Visual Magnitude. If you used the 1997 Parallax value, 24 Ursae Majoris absolute magnitude is 1.99 If you used the 2007 Parallax value, 24 Ursae Majoris absolute magnitude is 2.02.

Visible from Earth

24 Ursae Majoris is visible from Earth. The lower the Apparent Magnitude of a star or other object is, the easier it is to see in the night sky. An object with a magnitude greater than 6.5 can not be seen without the aid of a telescope or other device.

24 Ursae Majoris Distance from Earth

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 30.89000 which means 24 Ursae Majoris distance from Earth is 105.59 light years away from Earth or 32.37 parsecs. If you want that in miles, it is about 620,724,053,154,457.38, based on 1 Ly = 5,878,625,373,183.61 miles.

In 2007, Hipparcos data was revised with a new parallax of 31.32000 which puts 24 Ursae Majoris distance from Earth as 104.14 light years or 31.93 parsecs. It should not be taken as though the star is moving closer or further away from Earth. It is purely that the distance was recalculated.

Using the 2007 distance, the star is roughly 6,585,989.372 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. The star's Galacto-Centric Distance is 7,420 Parsecs or 24,201.32 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A*.

Alternative Names and Meanings

• The Id of the star in the Yale Bright Star Catalogue is HR3771.
• HIP46977 is the reference name for the star in the Hipparcos Star Catalogue.
• The Id of the star in the Henry Draper catalogue is HD82210. The catalogue was started by the American doctor and has been expanded on over the years.
• The Gliese ID of the star is GL 355.1. The star was part of the original catalogue devised by German Astronomer Wilheim Gliese of stars located within 20 parsecs of Earth. Star Names
• The star is catalogued in the Tycho-2 star catalogue as TYC-4376-2052-1. The catalogue lists 2 millions stars and its homepage is E.S.A.
• Flamsteed designations such as 24 Ursae Majoris (24 Uma) are named after the creator, Sir John Flamsteed. Sir John named the stars in the constellation with a number and its latin name, this star's Flamsteed designation is 24 Ursae Majoris. The Flamsteed name can be shortened to 24 Uma.
• 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 +70 565.

24 Ursae Majoris Travel Time

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.

Mach 1 is the speed of sound, Mach 2 is twice the speed of sound. Corncorde before it was retired was the fastest commercial airline across the Atlantic and only one that could do Mach 2.

Description	Speed (m.p.h.)	Time (years)
Walking	4	17,459,503,936.015
Car	120	581,983,464.534
Airbus A380	736	94,888,608.348
Mach 1	767.269	91,021,552.733
Mach 2	1,534.54	45,510,717.051
New Horizons	33,000	2,116,303.507
Speed of Light	670,616,629	104.14

Variable Type

The star is a RS Canum Venaticorum 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. 24 Ursae Majoris brightness ranges from a magnitude of 4.717 to a magnitude of 4.672 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 0.0 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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