U Camelopardalis is a semiregular variable

star A star is a luminous spheroid of plasma (physics), plasma held together by Self-gravitation, self-gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night sk ...

in the

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The first constellati ...

Camelopardalis Camelopardalis is a large but faint constellation of the northern sky representing a giraffe. The constellation was introduced in 1612 or 1613 by Petrus Plancius. Some older astronomy books give Camelopardalus or Camelopardus as alternative form ...

. Based on

parallax Parallax is a displacement or difference in the apparent position of an object viewed along two different sightline, lines of sight and is measured by the angle or half-angle of inclination between those two lines. Due to perspective (graphica ...

measurements made by the

Hipparcos ''Hipparcos'' was a scientific satellite of the European Space Agency (ESA), launched in 1989 and operated until 1993. It was the first space experiment devoted to precision astrometry, the accurate measurement of the positions and distances of ...

spacecraft A spacecraft is a vehicle that is designed spaceflight, to fly and operate in outer space. Spacecraft are used for a variety of purposes, including Telecommunications, communications, Earth observation satellite, Earth observation, Weather s ...

, it is located about 3,000

light-year A light-year, alternatively spelled light year (ly or lyr), is a unit of length used to express astronomical distances and is equal to exactly , which is approximately 9.46 trillion km or 5.88 trillion mi. As defined by the International Astr ...

s (1,000

parsec The parsec (symbol: pc) is a unit of length used to measure the large distances to astronomical objects outside the Solar System, approximately equal to or (AU), i.e. . The parsec unit is obtained by the use of parallax and trigonometry, and ...

s) away from the

Earth Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...

. Its apparent

visual magnitude Apparent magnitude () is a measure of the brightness of a star, astronomical object or other celestial objects like artificial satellites. Its value depends on its intrinsic luminosity, its distance, and any extinction of the object's light ca ...

is about 8, which is dim enough that it cannot be seen with the unaided eye. The spectral type of U Camelopardalis in the revised MK system is C-N5, which indicates a classical carbon star spectrum approximately corresponding to late K or early M. The C₂ index is 5.5 which is typical of a C-N star. It is also given an alternative spectral type of MS4, indicating a star similar to an M4 class but with somewhat enhanced ZrO bands. The spectral type may vary between C3,9 and C6,4e. UCamLightCurve

In 1891,

Williamina Fleming Williamina Paton Stevens Fleming (15 May 1857 – 21 May 1911) was a pioneering Scottish astronomer, who made significant contributions to the field despite facing gender biases. She was a single mother hired by the director of the Harvard Co ...

announced that the star (then known as DM +62°.596) is a variable star, based on 13 photographs taken in 1890 and 1891. It was listed with its

variable star designation In astronomy, a variable-star designation is a unique identifier given to variable stars. It extends the Bayer designation format, with an identifying label (as described below) preceding the Latin genitive of the name of the constellation in whic ...

, U Camelopardalis, in Annie Jump Cannon's 1907 work ''Second Catalog of Variable Stars''. U Camelopardalis is a

carbon star A carbon star (C-type star) is typically an asymptotic giant branch star, a luminous red giant, whose Stellar atmosphere, atmosphere contains more carbon than oxygen. The two elements combine in the upper layers of the star, forming carbon monox ...

. These types of stars have greater levels of

carbon Carbon () is a chemical element; it has chemical symbol, symbol C and atomic number 6. It is nonmetallic and tetravalence, tetravalent—meaning that its atoms are able to form up to four covalent bonds due to its valence shell exhibiting 4 ...

in their atmospheres than

oxygen Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), non ...

, which means they form carbon compounds that make the star appear strikingly red. U Camelopardalis is nearly 4 magnitudes fainter at blue wavelengths than in the centre of the visual range. In the

infrared Infrared (IR; sometimes called infrared light) is electromagnetic radiation (EMR) with wavelengths longer than that of visible light but shorter than microwaves. The infrared spectral band begins with the waves that are just longer than those ...

K band it has an apparent magnitude of 0.37. Its brightness varies without a dominant period and it is classified as semi-regular, although a period of 400 days has been published. In the V photometric band the brightness varies by around half a magnitude, but the amplitude is nearly two magnitudes at blue wavelengths. The maximum visual magnitude has been given as 7.2. The shell of gas surrounding U Camelopardalis was imaged by the

Hubble Space Telescope The Hubble Space Telescope (HST or Hubble) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the Orbiting Solar Observatory, first space telescope, but it is one of the largest and most ...

in 2012, showing a nearly perfect sphere of gas surrounding the star. U Cameloparadlis has a 10th magnitude companion 308" away. It is a B8

main sequence In astronomy, the main sequence is a classification of stars which appear on plots of stellar color index, color versus absolute magnitude, brightness as a continuous and distinctive band. Stars on this band are known as main-sequence stars or d ...

star, hotter but less luminous than U Cam itself. They are not thought to be physically associated.

References

{{DEFAULTSORT:U Camelopardalis Carbon stars Camelopardalis Camelopardalis, U 022611 017257 Durchmusterung objects Semiregular variable stars Asymptotic-giant-branch stars