U Cephei
 U Cephei, as seen during theDigitized Sky Survey | |
| Constellation | Cepheus |
|---|---|
| Coordinates |
|
| Distance | 825.73ly(253.16pc) |
| Epoch | J2000 |
| Characteristics | |
| Apparentm | 6.9 |
| Spectral type | G8III |
| Planets | 0 |
| Orbit | |
| Eccentricity | 0.07560 |
U Cepheiis an eclipsingbinary stardiscovered in 1880.[1][2]It consists of a blue-whitemain sequence starofspectral typeB7Ve that iseclipsedevery two and a half days by a less bright giant of type G8III-IV.[3]The drop in brightness lasts 4 hours and the system sees itsapparent magnitudeincrease from 6.7 to 9.2. The total eclipse then lasts 2 hours before an increase in brightness for 4 hours. The two stars, separated by less than 10,000,000 kilometres (6,200,000 mi), exchange matter. This transfer towards the blue giant caused the system's orbital period to lengthen by 4 minutes during the 20th century. U Cephei is one of the brightest eclipsing binaries. Located near the north celestial pole, it can be monitored continuously with a 60 millimetertelescope.[3]
The system has two visual companions listed in the double and multiple star catalogs. U Cephei B is a twelfth magnitude star that, as of 2016, was located at anangular distanceof 13.9arcsecondsand at aposition angleof 63° from U Cephei A. It exhibits a commonproper motionwith the system, which indicates that it is physically linked to it. U Cephei C is another twelfth magnitude star, but it is only a purely optical double and its proximity to the system is a coincidence.[5]
See also
[edit]References
[edit]- ^"U Cephei | astronomy | Britannica".britannica.Retrieved2024-09-27.
- ^Gimenez, A.; Guinan, E. F.; Gonzalez-Riestra, R. (1993-01-01)."UV and X-ray emission in the interacting binary U Cephei".Astronomy and Astrophysics Supplement Series.97(1).ISSN0365-0138.
- ^ab"U Cephei Star Facts - Universe Guide".universeguide.January 25, 2015.Retrieved2024-09-27.
- ^"MAST: Barbara A. Mikulski Archive for Space Telescopes".Space Telescope Science Institute.Retrieved1 October2024.
- ^Knott, George (June 9, 1882)."On the Variable Star U Cephei".Monthly Notices of the Royal Astronomical Society.RetrievedSeptember 27,2024.
