- Iota Ursae Majoris
-
Iota Ursae Majoris A/B/C Observation data
Epoch J2000 Equinox J2000Constellation Ursa Major Right ascension 08h 59m 12.4s Declination +48° 02′ 30″ Apparent magnitude (V) 3.12/10.1/10.3 Characteristics Spectral type A7 IV/dM1 J/? U−B color index 0.07 B−V color index 0.19 Variable type Suspected Astrometry Radial velocity (Rv) 7.6 km/s Proper motion (μ) RA: -441.12 mas/yr
Dec.: -215.21 mas/yrParallax (π) 68.32 ± 0.79 mas Distance 47.7 ± 0.6 ly
(14.6 ± 0.2 pc)Absolute magnitude (MV) 2.29 Details Mass 1.7 M☉ Radius 1.5 R☉ Luminosity 9 L☉ Temperature 8165 K Rotation 151 km/s. Other designations Iota Ursae Majoris (ι UMa, ι Ursae Majoris) is a star system in the constellation Ursa Major. It is approximately 47.7 light years from Earth. It has the traditional names Talitha, Talitha Borealis and Alphikra Borealis, and was also named Dnoces ("Second," backwards) after Edward H. White II, an Apollo 1 astronaut. The name was invented by his fellow astronaut Gus Grissom as a practical joke.[1]
The Iota Ursae Majoris system is composed of two binary stars. The brightest component, Iota Ursae Majoris A, is a white A-type subgiant with an apparent magnitude of +3.12. It is a spectroscopic binary whose components have an orbital period of 4028 days.
The companion binary is composed of the 9th magnitude Iota Ursae Majoris B and the 10th magnitude Iota Ursae Majoris C. These two stars orbit around each other with a period of 39.7 years, and are separated by roughly 0.7 arcseconds, or at least 10 AU. The two binary systems orbit around each other once every 818 years. The apparent separation between the two binaries is rapidly decreasing as they follow their orbits. In 1841 when the B component was first discovered, they had a separation of 10.7 arcseconds, or at least 156 AU. By 1971 their separation had decreased to 4.5 arcseconds, or at least 66 AU.
See also
References
- ^ Apollo 15 Lunar Surface Journal, Post-landing Activities, commentary at 105:11:33
External links
- NightSky Friday: Rotanev, Derf, Navi, and other Backward Star Names – Space.com article
- ARICNS
- Talitha by Professor Jim Kaler.
Star systems within 40–50 light-years from Earth with brightest member's absolute magnitude of +8.5 or brighter.Alpha Ophiuchi «Rasalhague» (46.7 ± 0.6 ly; 1 star)Capella (42.2 ± 0.5 ly; 4 stars)Alpha Cephei «Alderamin» (48.8 ± 0.4 ly; 1 star)Iota Ursae Majoris «Talitha Borealis» (47.7 ± 0.6 ly; 4 stars)Beta Trianguli Australis (40.2 ± 0.3 ly; 2 stars)‡ • Theta Ursae Majoris «Alhaud» (44.0 ± 0.4 ly; 3 stars) • Delta Aquilae «Denebokab» (50.1 ± 0.6 ly; 3 stars)‡36 Ursae Majoris (41.9 ± 0.4 ly; 2 stars) • Upsilon Andromedae (43.9 ± 0.4 ly; 2 stars, 4 planets: planet b • planet c • planet d • planet e) • 10 Tauri (44.8 ± 0.5 ly; 2 stars) • Iota Piscium (45.0 ± 0.5 ly; 1 star) • Alpha Fornacis «Dalim» (46.0 ± 0.4 ly; 2 stars) • Theta Boötis «Asellus Primus» (47.5 ± 0.4 ly; 2 stars) • Psi Capricorni «Yue» (47.9 ± 0.6 ly; 1 star) • Alpha Corvi «Alchiba» (48.2 ± 0.5 ly; 1 star) • Eta Leporis (49.1 ± 0.5 ly; 1 star) • Nu Phoenicis (49.1 ± 0.5 ly; 1 star) • Sigma Boötis «Hemelein Secunda» (50.4 ± 0.6 ly; 2 stars)‡Beta Aquilae «Alshain» (44.7 ± 0.5 ly; 2 stars) • b (31) Aquilae (49.4 ± 0.6 ly; 3 stars)Rho¹ (55) Cancri (40.9 ± 0.4 ly; 2 stars, 5 planets: planet e • planet b • planet c • planet f • planet d) • HR 483 (41.2 ± 0.4 ly; 2 stars) • Lambda Aurigae «Al Hurr» (41.2 ± 0.5 ly; 2 stars) • HR 683 (41.4 ± 0.4 ly; 1 star) • i (44) Boötis (41.6 ± 0.3 ly; 3 stars) • HR 6094 (42.0 ± 0.5 ly; 2 stars, 1 planet: planet b) • HR 6998 (42.4 ± 0.5 ly; 1 star) • 58 Eridani (43.4 ± 0.5 ly; 1 star) • HR 8501 (44.4 ± 0.4 ly; 2 stars) • 18 Scorpii (45.7 ± 0.6 ly; 1 star) • 47 Ursae Majoris (45.9 ± 0.4 ly; 1 star, 3 planets: planet b • planet c • planet d) • 26 Draconis (45.9 ± 0.3 ly; 3 stars) • Pi¹ Ursae Majoris (46.6 ± 0.5 ly; 1 star) • 72 Herculis (46.9 ± 0.4 ly; 1 star) • Nu² Lupi (47.5 ± 0.5 ly; 1 star, 3 planets: planet b • planet c • planet d) • HR 7898 (47.8 ± 0.6 ly; 1 star) • Psi Serpentis (47.9 ± 0.6 ly; 2 stars) • HR 3862 (48.5 ± 0.5 ly; 1 star) • 20 Leonis Minoris «Cor» (48.6 ± 0.6 ly; 1 star) • HD 176051 (48.9 ± 0.4 ly; 2 stars, 1 planet: planet b) • Mu Arae (49.8 ± 0.6 ly; 1 star, 4 planets: planet d • planet e • planet b • planet c)‡ • 51 Pegasi (50.1 ± 0.6 ly; 1 star, 1 planet: planet b «Bellerophon»)‡ • HR 2007 (50.8 ± 0.9 ly; 1 star, 1 planet: planet b)‡HR 4587 (42.1 ± 0.4 ly; 1 star) • Gamma Cephei «Errai» (45.0 ± 0.3 ly; 2 stars, 1 planet: planet b) • Eta Cephei «Al Agemim» (46.8 ± 0.3 ly; 1 star)HR 3384 (39.7 ± 0.3 ly; 1 star)‡ • HR 1925 (39.9 ± 0.4 ly; 1 star)‡ • Gliese 435 (40.8 ± 0.5 ly; 1 star) • HR 3259 (41.0 ± 0.4 ly; 1 star, 3 planets: planet b • planet c • planet d) • Gliese 349 (41.4 ± 0.6 ly; 1 star) • HR 6518 (41.7 ± 0.3 ly; 1 star) • HD 40307 (41.8 ± 0.3 ly; 1 star, 3 planets: planet b • planet c • planet d) • Gliese 428 (42.0 ± 1.0 ly; 2 stars) • Gliese 707 (42.3 ± 0.7 ly; 1 star) • Gliese 204 (42.3 ± 0.5 ly; 1 star) • Gliese 167 (42.7 ± 0.3 ly; 1 star) • Gliese 425 (42.9 ± 1.0 ly; 2 stars) • Gliese 716 (43.1 ± 0.5 ly; 1 star) • Gliese 174 (44.0 ± 0.8 ly; 1 star) • Gliese 656 (44.6 ± 0.6 ly; 1 star) • Gliese 5 (44.7 ± 0.5 ly; 2 stars) • AB Doradus (48.7 ± 0.4 ly; 2 stars)In left column are stellar classes of primary members of star systems. ‡Distance error margin extends out of declared distance interval. Italic are systems possibly located within declared distance interval, but probably not.
This subgiant star-related article is a stub. You can help Wikipedia by expanding it.
