Iota Ursae Majoris

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Template:Short description

Iota Ursae Majoris
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Location of ι Ursae Majoris (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Ursa Major
Right ascension Template:RA[1]
Declination Template:DEC[1]
Apparent magnitude (V) 3.14[2]/10.1/10.3
Characteristics
Spectral type A7V(n)[3] + M3V + M4V[4]
U−B Template:Engvar +0.08[2]
B−V Template:Engvar +0.19[2]
Variable type Suspected
Astrometry
Radial velocity (Rv)+9.0[5] km/s
Proper motion (μ) RA: -441.29[1] mas/yr
Dec.: -215.32[1] mas/yr
Parallax (π)68.92±0.16 mas[1]
DistanceTemplate:Rnd ± Template:Rnd ly
(Template:Rnd ± Template:Rnd pc)
Absolute magnitude (MV)+2.31[6]
Orbit[7]
Primaryι UMa A
Companionι UMa BC
Period (P)2084 ± 15 yr
Semi-major axis (a)16.7 ± 0.3″
Eccentricity (e)0.90 ± 0.02
Inclination (i)54 ± 4°
Longitude of the node (Ω)134 ± 2°
Periastron epoch (T)B 2029 ± 1
Argument of periastron (ω)
(secondary)		23 ± 5°
Details
ι UMa Aa
Mass1.7 ± 0.1[4] Template:Solar mass
Radius1.67[8] Template:Solar radius
Luminosity8.98[8] Template:Solar luminosity
Surface gravity (log g)4.30 ± 0.07[4] cgs
Temperature8,242[9] K
Metallicity [Fe/H]Script error: No such module "val".[8] dex
Rotational velocity (v sin i)154[10] km/s
Age620[11] Myr
Ab
MassScript error: No such module "val".[4][12] Template:Solar mass
Metallicity [Fe/H]{{{metal_fe2}}} dex
ι UMa B
Mass0.35 ± 0.05[4] Template:Solar mass
Radius0.46[13] Template:Solar radius
ι UMa C
Mass0.30 ± 0.05[4] Template:Solar mass
Radius0.43[13] Template:Solar radius
Metallicity [Fe/H]{{{metal_fe2}}} dex
Other designations
Talitha, ι Ursae Majoris, ι UMa, Iota UMa, 9 Ursae Majoris, BD+48 1707, FK5 335, GJ 331, HD 76644, HIP 44127, HR 3569, SAO 42630, WDS J08592+4803A,BC.[3]
Database references
SIMBADι UMa
ι UMa A
ι UMa BC
ARICNSι UMa A
ι UMa B
ι UMa C

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Iota Ursae Majoris (ι Ursae Majoris, abbreviated Iota UMa, ι UMa), also named Talitha Template:IPAc-en,[14] is a star system in the northern circumpolar constellation of Ursa Major. It has an apparent visual magnitude of 3.14,[2] making it visible to the naked eye and placing it among the brighter members of this constellation. Based upon parallax measurements, it is located at a distance of Script error: No such module "convert". from the Sun.

Nomenclature

ι Ursae Majoris (Latinised to Iota Ursae Majoris) is the star's Bayer designation.

File:C2020F3.P1023630.jpg
Iota Ursae Majoris in conjunction with comet NEOWISE on 18 July 2020 17° above the north horizon of Berlin

The traditional name Talitha, (which was shared with Kappa Ursae Majoris) comes from the Arabic phrase Script error: No such module "lang". (Template:Langx), a mis-transcription of Script error: No such module "lang". (Template:Langx), which means "the third spring, or leap, of the ghazal".[15] The term Borealis meaning "the north side" in Latin. In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[16] to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016[17] included a table of the first two batches of names approved by the WGSN; which included Talitha for this star.

In Chinese, Script error: No such module "Lang". (Script error: No such module "Lang".), meaning Three Steps, refers to an asterism consisting of ι Ursae Majoris, Kappa Ursae Majoris, Lambda Ursae Majoris, Mu Ursae Majoris, Nu Ursae Majoris and Xi Ursae Majoris. Consequently, the Chinese name for ι Ursae Majoris itself is Script error: No such module "Lang". (Script error: No such module "Lang"., Template:Langx).[18]

The star was also dubbed 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.[19]

Stellar system

The Iota Ursae Majoris system is composed of two sets of binary stars. The two binary systems orbit around each other once every 2,084 years.[4] 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. This system appears to be dynamically unstable with a high likelihood and may become disrupted on a time scale on the order of 105 years.[20]

The brightest component is a white A-type subgiant. It is a member of a spectroscopic binary system whose components have an orbital period of 4,028 days. The companion, which has not been directly observed, is thought to be a white dwarf with a mass of Template:Solar mass.[4]

The companion binary is composed of the 9th magnitude and 10th magnitude stars, both of which are red dwarfs.[4] These two red dwarfs, designated Iota Ursae Majoris B and C respectively, orbit around each other with a period of 39.7 years, and are separated by roughly 0.7 arcseconds, or at least 10 AU. This pair may be the source of the X-ray emission detected from this system.[21]

See also

References

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  1. ↑ a b c d e Script error: No such module "Citation/CS1".
  2. ↑ a b c d Script error: No such module "Citation/CS1".
  3. ↑ a b Template:Cite simbad
  4. ↑ a b c d e f g h i Script error: No such module "Citation/CS1".
  5. ↑ Script error: No such module "citation/CS1".
  6. ↑ Script error: No such module "citation/CS1".
  7. ↑ Script error: No such module "citation/CS1".
  8. ↑ a b c Script error: No such module "citation/CS1". Iota Ursae Majoris' database entry at VizieR.
  9. ↑ Script error: No such module "citation/CS1".
  10. ↑ Script error: No such module "citation/CS1".
  11. ↑ Script error: No such module "citation/CS1".
  12. ↑ Script error: No such module "Citation/CS1".
  13. ↑ a b Script error: No such module "citation/CS1".
  14. ↑ Script error: No such module "citation/CS1".
  15. ↑ Richard Hinckley Allen :Star Names — Their Lore and Meaning - Ursa Major, the Greater Bear
  16. ↑ Script error: No such module "citation/CS1".
  17. ↑ Script error: No such module "citation/CS1".
  18. ↑ Template:In lang (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 21 日 Template:Webarchive
  19. ↑ Script error: No such module "citation/CS1".. Commentary at 105:11:33.
  20. ↑ Script error: No such module "citation/CS1".
  21. ↑ Script error: No such module "citation/CS1".

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External links

Template:Stars of Ursa Major

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