Astronomy:Zeta Herculis Moving Group

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Zeta Herculis Moving Group is a set of stars that share a common motion through space. The existence of this moving group was first published in 1958 by Olin J. Eggen. Based upon the high velocity motion of the star Zeta Herculis through space, he searched for stars that were following a similar velocity and direction. A total of 22 candidate members were identified. Among the group members he included β Hydri, ρ Persei, η Reticuli, φ1 Lupi, ζ Herculis and ε Octantis. He estimated the group velocity at 74.5 km/s.[1] In 1970, Richard Woolley refined the list to ten stars, including φ2 Pavonis and ζ1/ζ2 Reticuli as members of this cluster.[2]

The parallel motion of the stars in this group implies a common origin, and hence a similar age and composition. The membership of ζ Herculis and HD 158614 came into question because their composition appeared to show they were much younger than other members of the group. The average age was estimated as 8.2 × 109 years[failed verification], while ζ Herculis was estimated as 6.3 billion years in age[failed verification].[3] However, a statistical analysis of the metallicity for stars in this group showed no difference from a comparison sample, indicating that it may not be possible to determine more information about this group based on the composition of its members.[4]

Members of the ζ Her moving group (1958 version)[1]
Name Constellation B F HD HIP vis.
mag. 		Dist. (ly) Sp. class Notes
ζ Her Hercules ζ 40 150680 81693 2.81 35 F9IV
β Hyi Hydrus β 2151 2021 2.82 24 G2IV
ρ Per Perseus ρ 25 19058 14354 3.32 325 M3IIIvar Gorgonea Tertia
φ1 Lup Lupus φ1 88 136422 75177 3.57 326 K5III
47 Psc Pisces 47 2411 2219 5.01 490 M3IIIvar TV Psc
ε Oct Octans ε 210967 110256 5.09 268 M6III BO Oct
η Ret Reticulum η 28093 20384 5.24 380 G7III
84 Vir Virgo 84 119425 66936 5.35 217 K1III
HD 71377 Puppis 71377 41395 5.52 268 K1/K2III
HD 43899 Columba 43899 29842 5.54 302 K2III
HD 100733 Centaurus C1 100733 56518 5.64 652 M3III V763 Cen
HD 150275 Ursa Minor 150275 80850 6.35 408 K1III
29 LMi Leo Minor 29 90250 51047 6.49 413 K1III
HD 221354 Cassiopeia 221354 116085 6.76 55 K2V Gliese 895.4
HD 9166 Cassiopeia 9166 7166 6.81 485 K3III
HD 30455 Taurus 30455 22349 6.96 100 G2V...
71 Leo Leo 71 98824 55533 7.03 773 K1III
HD 219829 Cassiopeia 219829 115112 8.09 106 K0V...
HD 68788 Camelopardalis 68788 40848 8.35 101 K1V
HD 209134 Pisces Austrinus 209134 9.11 K3V
HD 89668 Sextans 89668 50657 9.42 106 F8V
HD 106364 Camelopardalis 106364 10.03 K2III+...
Members of the ζ her moving group (1970 version)[2]
Name Constellation B F HD HIP vis.
mag. 		Dist. (ly) Sp. class Notes
ζ Her Hercules ζ 40 150680 81693 2.81 35 F9IV
β Hyi Hydrus β 2151 2021 2.82 24 G2IV
φ2 Pav Pavo φ2 196378 101983 5.11 79 F8V
ζ2 Ret Reticulum ζ2 20807 15371 5.24 39 G1V
HD 158614 Ophiuchus 158614 85667 5.31 54 G8IV-V Gliese 678
ζ1 Ret Reticulum ζ1 20766 15330 5.53 40 G2V
1 Hya Hydra 1 70958 41211 5.61 89 F3V
HD 14680 Fornax 14680 10977 8.79 100 F3V
HIP 59198 Virgo 59198 11.69 94 K7 Gliese 456

References

  1. ↑ 1.0 1.1 Eggen, O. J. (1958). "Stellar groups. II. The ζ Herculis, ε Indi and 61 Cygni groups of high-velocity stars". Monthly Notices of the Royal Astronomical Society 118 (2): 154–. doi:10.1093/mnras/118.2.154. Bibcode: 1958MNRAS.118..154E. 
  2. ↑ 2.0 2.1 Woolley, Richard van der Reit (1970). "Box Orbits of Nearby Stars". Gordon and Breach. pp. 95–160. 
  3. ↑ Porto de Mello, G. F.; da Silva, L. (November 1991). "On the physical existence of the Zeta HER moving group - A detailed analysis of Phi exp 2 Pavonis". Astronomical Journal 102: 1816–1825. doi:10.1086/116006. Bibcode: 1991AJ....102.1816P. 
  4. ↑ Taylor, B. J. (2000). "A statistical analysis of the metallicities of nine old superclusters and moving groups". Astronomy and Astrophysics 362: 563–579. Bibcode: 2000A&A...362..563T. 



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