Zeta Herculis

Short description: Multiple star system in the constellation Hercules

Zeta Herculis

Location of ζ Herculis (circled)

Observation data
Equinox J2000.0]] (ICRS)
Constellation | Hercules
Right ascension |  16h 41m 17.16104s[1]
Declination | +31° 36′ 09.7873″[1]
Apparent magnitude (V) | 2.81[2]
Characteristics
Spectral type | F9 IV + G7 V[3]
U−B color index | +0.21[2]
B−V color index | +0.65[2]
Variable type | Suspected
Astrometry
Radial velocity (Rv)| –68.43[4] km/s
Proper motion (μ)|  RA: –461.52[1] mas/yr
Dec.: +342.28[1] mas/yr
Parallax (π)| 93.32 ± 0.47[1] mas
Distance| 35.0 ± 0.2 ly
(10.72 ± 0.05 pc)
Absolute magnitude (MV)| 2.65[5]
Absolute bolometric
magnitude (Mbol)| 2.699 / 5.254[6]
Orbit[7]
Period (P)| 34.45 yr
Semi-major axis (a)| 1.33″
Eccentricity (e)| 0.46
Inclination (i)| 131°
Longitude of the node (Ω)| 50°
Periastron epoch (T)| 1967.7
Argument of periastron (ω)
(secondary)| 111°
Details
ζ Her A
Mass| 1.45±0.01[6] M☉
Radius| 2.56–2.61[6] R☉
Luminosity| 6.55±0.39[6] L☉
Surface gravity (log g)| 3.4–3.6[6] cgs
Temperature| 5,820±50[6] K
Metallicity [Fe/H]| 0.04±0.003[6] dex
Rotational velocity (v sin i)| 4.8[5] km/s
Age| 6.2[8] Gyr
ζ Her B
Mass| 0.98±0.02[6] M☉
Radius| 0.915–0.920[6] R☉
Luminosity| 0.62±0.06[6] L☉
Temperature| 5,300±150[6] K
Other designations

Database references
SIMBAD| data

Zeta Herculis, Latinized from ζ Herculis, is a multiple star system in the constellation Hercules. It has a combined apparent visual magnitude of 2.81,[2] which is readily visible to the naked eye. Parallax measurements put it at a distance of about 35.0 light-years (10.7 parsecs) from Earth.[1]

The primary member is a subgiant star that is somewhat larger than the Sun and has just begun to evolve away from the main sequence as the supply of hydrogen at its core becomes exhausted. It is orbited by a smaller companion star at a mean angular separation of 1.5 arcseconds, which corresponds to a physical separation of about 15 Astronomical Units.[6] This distance is large enough so that the two stars do not have a significant tidal effect on each other. The stars orbit each other over a period of 34.45 years, with a semi-major axis of 1.33" and an eccentricity of 0.46.[7]

Component A has a stellar classification of F9 IV.[3] It has about 2.6 times the radius of the Sun and 1.45 times the Sun's mass. This star is radiating more than six times the luminosity of the Sun at an effective temperature of 5,820 K. The secondary component (Component B) is about the same size and mass as the Sun, with an effective temperature of 5,300 K. Both stars are rotating slowly.[6] There may be a faint third member of this system, although little is known about it.[9]

The dual nature of this system was reported by F. G. W. Struve in 1826.[10] The pair orbit each other with a period of 34.45 years and an eccentricity of 0.46.[7] The magnitude difference between the A-B pair is 1.52 ± 0.04 magnitudes (at 700 nm).[11] Two astrometric studies have failed to detect a third component to the A-B binary.[11][7]

This system forms part of the Zeta Herculis moving group of stars. This group includes: φ2 Pavonis, ζ Reticuli, 1 Hydrae, Gl 456, Gl 678, and Gl 9079.[12]

## References

1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode: 2007A&A...474..653V
2. ↑ 2.0 2.1 2.2 2.3 Johnson, H. L. et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory 4 (99): 99, Bibcode: 1966CoLPL...4...99J
3. ↑ 3.0 3.1 Edwards, T. W. (April 1976), "MK classification for visual binary components", Astronomical Journal 81: 245–249, doi:10.1086/111879, Bibcode: 1976AJ.....81..245E
4. ↑ Tokovinin, A. A.; Smekhov, M. G. (January 2002), "Statistics of spectroscopic sub-systems in visual multiple stars", Astronomy and Astrophysics 382: 118–123, doi:10.1051/0004-6361:20011586, Bibcode: 2002A&A...382..118T, https://zenodo.org/record/896317
5. ↑ 5.0 5.1 Pizzolato, N.; Maggio, A.; Sciortino, S. (September 2000), "Evolution of X-ray activity of 1-3 Msun late-type stars in early post-main-sequence phases", Astronomy and Astrophysics 361: 614–628, Bibcode: 2000A&A...361..614P
6. ↑ 6.00 6.01 6.02 6.03 6.04 6.05 6.06 6.07 6.08 6.09 6.10 6.11 6.12 Morel, P. et al. (November 2001), "The zeta Herculis binary system revisited. Calibration and seismology", Astronomy and Astrophysics 379: 245–256, doi:10.1051/0004-6361:20011336, Bibcode: 2001A&A...379..245M
7. ↑ 7.0 7.1 7.2 7.3 Söderhjelm, Staffan (January 1999), "Visual binary orbits and masses POST HIPPARCOS", Astronomy and Astrophysics 341: 121–140, Bibcode: 1999A&A...341..121S
8. ↑ Barry, Don C.; Cromwell, Richard H.; Hege, E. Keith (April 1987), "Chromospheric activity and ages of solar-type stars", Astrophysical Journal, Part 1 315: 264–272, doi:10.1086/165131, Bibcode: 1987ApJ...315..264B
9. ↑ Zhuchkov, R. Ya.; Orlov, V. V.; Rubinov, A. V. (May 2006), "Multiple stars with low hierarchy: stable or unstable?", Publications of the Astronomical Observatory of Belgrade 80: 155–160, Bibcode: 2006POBeo..80..155Z
10. ↑ Mason, B. D. et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal 122 (6): 3466–3471, doi:10.1086/323920, Bibcode: 2001AJ....122.3466M.
11. ↑ 11.0 11.1 Hutter, D. J.; Zavala, R. T.; Tycner, C.; Benson, J. A.; Hummel, C. A.; Sanborn, J.; Franz, O. G.; Johnston, K. J. (2016-11-01). "Surveying the Bright Stars by Optical Interferometry. I. A Search for Multiplicity among Stars of Spectral Types F-K". The Astrophysical Journal Supplement Series 227 (1): 4. doi:10.3847/0067-0049/227/1/4. ISSN 0067-0049. Bibcode: 2016ApJS..227....4H.
12. ↑ de Mello, G. F. Porto; da Silva, L. (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

## External links

* "Gl 635". ARICNS. http://wwwadd.zah.uni-heidelberg.de/datenbanken/aricns/cnspages/4c01326.htm.
* "zet Her". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=zet+Her.
* Prof. Jim Kaler. "Zeta Herculis". Stars. http://stars.astro.illinois.edu/sow/zetaher.html.

* v
* t
* e

Hercules constellation

Stars (list)|

| Bayer|

* α (Rasalgethi)
* β (Kornephoros)
* γ
* δ (Sarin)
* ε
* ζ
* η
* θ
* ι
* κ (Marsic)
* λ (Maasym)
* μ
* ν
* ξ
* ο
* π
* ρ
* σ
* τ
* υ
* φ
* χ
* ω (Cujam)

|

Flamsteed|

* 2
* 4
* 5 (r)
* 8
* 9
* 10
* 12
* 13
* 14
* 15
* 16
* 17
* 18
* 19
* 21 (o)
* 25
* 26
* 28 (n)
* 29 (h)
* 30 (g)
* 31
* 32
* 33
* 34
* 36
* 37 (m)
* 38
* 39
* 41
* 42
* 43 (i)
* 45 (l)
* 46
* 47 (k)
* 48
* 49
* 50
* 51
* 52
* 53
* 54
* 56
* 57
* 59 (d)
* 60
* 61
* 62
* 63
* 68 (u)
* 69 (e)
* 70
* 72 (w)
* 73
* 74
* 77 (x)
* 78
* 79
* 82 (y)
* 83
* 84
* 87
* 88 (z)
* 89
* 90 (f)
* 93
* 95
* 96
* 97
* 98
* 99 (b)
* 100
* 101
* 102
* 104 (A)
* 105
* 106
* 107 (t)
* 108
* 109
* 110
* 111
* 112
* 113
* 32 Oph
* 33 Oph
* 34 Oph
* 48 Ser (q)
* 49 Ser

Variable|

* U
* X
* Z
* RS
* RU
* RX
* SS
* ST
* SY
* SZ
* TT
* TU
* TW
* TX
* UU
* UX
* VX
* VZ
* YY
* AC
* AD
* AH
* AK
* AM
* AP
* AR
* AW
* BB
* BL
* CC
* CT
* DI
* DQ
* DY
* HS
* LQ
* LT
* MM
* OP
* PW
* V338
* V443
* V446
* V451
* V533
* V535
* V600
* V624
* V636
* V640
* V642
* V644
* V656
* V728
* V771
* V772
* V773
* V775
* V777
* V792
* V795
* V814
* V815
* V819
* V822
* V827
* V829
* V831
* V835
* V838
* V842
* V844
* V857
* V884
* V899
* V934
* V959
* V974

HR|

* 5950
* 5964
* 6050
* 6057
* 6087
* 6090
* 6091
* 6121
* 6152 (s)
* 6154
* 6157
* 6162
* 6169
* 6181
* 6183
* 6203
* 6208
* 6222
* 6227
* 6230
* 6239
* 6246
* 6256
* 6259
* 6264
* 6286
* 6287
* 6301
* 6307
* 6313
* 6325
* 6333
* 6336
* 6343
* 6351
* 6352
* 6362
* 6363
* 6364
* 6376
* 6377 (c)
* 6388
* 6399
* 6419
* 6430
* 6432
* 6443
* 6444
* 6455
* 6463
* 6466
* 6467
* 6481
* 6482
* 6488
* 6491
* 6499
* 6502
* 6506
* 6528
* 6531
* 6541
* 6542
* 6550
* 6959
* 6563
* 6564
* 6570
* 6584
* 6589
* 6591
* 6592
* 6594
* 6599
* 6604
* 6612
* 6619
* 6627
* 6638
* 6641
* 6642
* 6654
* 6655
* 6665
* 6669
* 6673
* 6674
* 6687
* 6697
* 6711
* 6722
* 6726
* 6728
* 6737
* 6744
* 6753
* 6763
* 6767
* 6768
* 6791
* 6792
* 6793
* 6799
* 6803
* 6806
* 6807
* 6814
* 6820
* 6824
* 6826
* 6852
* 6854
* 6867
* 6882
* 6885
* 6887
* 6904
* 6906
* 6917
* 6924
* 6943
* 6950
* 6955
* 6966
* 6977
* 6980
* 6981
* 6995
* 7047
* 7067
* 7079
* 7086
* 7148

HD|

* 146389
* 147506
* 149026 (Ogma)
* 149908
* 151044
* 154345
* 155061
* 155358
* 156074
* 156668
* 158038
* 161817
* 164595
* 164922

Gliese|

* 623
* 638
* 649
* 669
* 686
* 3991

Other|

* ADS 10075
* BD +13° 3324
* BD +17° 3248
* BD +22° 3406
* Furuhjelm 46
* GD 362
* HAT-P-14
* HAT-P-18
* Hercules X-1
* GSC 02620-00648
* GSC 03089-00929
* IRAS 18062+2410
* PG 1654+160
* PG 1658+441
* PG 1707+427
* PG 1716+426
* Ross 640
* WISE 1738+2732
* WISE 1741+2553
* WISE 1804+3117

Star clusters|

| Globular|

* Messier 13
* Messier 92
* NGC 6229

|

Nebulae|

| Planetary|

* Abell 39
* IC 4593
* NGC 6058
* NGC 6210

|

Galaxies|

| NGC|

* 6013
* 6028
* 6030
* 6032
* 6034
* 6035
* 6039
* 6040
* 6041
* 6042
* 6043
* 6044
* 6045
* 6046
* 6047
* 6052
* 6053
* 6054
* 6055
* 6056
* 6057
* 6060
* 6061
* 6062
* 6073
* 6074
* 6075
* 6078
* 6081
* 6083
* 6084
* 6098
* 6099
* 6106
* 6113
* 6132
* 6138
* 6141
* 6145
* 6146
* 6147
* 6148
* 6149
* 6150
* 6154
* 6155
* 6158
* 6159
* 6160
* 6161
* 6162
* 6163
* 6166
* 6168
* 6173
* 6174
* 6175
* 6177
* 6179
* 6180
* 6181
* 6184
* 6185
* 6186
* 6194
* 6195
* 6196
* 6197
* 6201
* 6203
* 6207
* 6212
* 6219
* 6224
* 6225
* 6228
* 6230
* 6233
* 6239
* 6241
* 6243
* 6255
* 6257
* 6261
* 6263
* 6264
* 6265
* 6267
* 6269
* 6270
* 6271
* 6272
* 6274
* 6276
* 6278
* 6279
* 6282
* 6283
* 6301
* 6308
* 6311
* 6312
* 6313
* 6314
* 6315
* 6320
* 6321
* 6323
* 6327
* 6329
* 6330
* 6332
* 6336
* 6339
* 6343
* 6347
* 6348
* 6349
* 6350
* 6351
* 6363
* 6364
* 6367
* 6371
* 6372
* 6375
* 6379
* 6389
* 6408
* 6417
* 6427
* 6429
* 6430
* 6431
* 6433
* 6442
* 6443
* 6446
* 6447
* 6452
* 6458
* 6460
* 6467
* 6468
* 6482
* 6484
* 6485
* 6486
* 6487
* 6490
* 6495
* 6500
* 6501
* 6504
* 6513
* 6518
* 6524
* 6527
* 6547
* 6548
* 6549
* 6550
* 6555
* 6560
* 6571
* 6574
* 6575
* 6576
* 6577
* 6579
* 6580
* 6581
* 6582
* 6585
* 6586
* 6587
* 6591
* 6593
* 6599
* 6600
* 6602
* 6610
* 6616
* 6619
* 6623
* 6627
* 6628
* 6632
* 6635
* 6641
* 6658
* 6660
* 6661
* 6674
* 6680
* 6697

|

Other|

* A2261-BCG
* Arp 272 (NGC 6050 and IC 1179)
* AT2018cow
* IC 1182
* Hercules (dwarf galaxy)
* Hercules A
* MCG+07-33-027
* PGC 214560
* QSR J1819+3845

Galaxy clusters|

* Abell 2152
* Abell 2199
* Hercules Cluster
* Hercules Superclusters
* Zwicky's Triplet

Other|

* Hercules–Corona Borealis Great Wall
* LBG-2377

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