AG Virginis

Short description: Eclipsing binary star in the constellation Virgo

AG Virginis

A visual band light curve for AG Virginis, plotted from ASAS data[1]

Observation data
Equinox J2000.0]] (ICRS)
Constellation | Virgo
Right ascension |  12h 01m 03.504s[2]
Declination | 13° 00′ 30.01″[2]
Apparent magnitude (V) | 8.51[3]
Characteristics
Spectral type | A7V-A9V[4]
B−V color index | 0.289±0.017[3]
Variable type | W UMa[5]
Astrometry
Proper motion (μ)|  RA: −2.740[2] mas/yr
Dec.: −18.255[2] mas/yr
Parallax (π)| 3.9564 ± 0.0621[2] mas
Distance| 820 ± 10 ly
(253 ± 4 pc)
Orbit[6]
Period (P)| 0.6426507 d
Semi-major axis (a)| 4.477 R☉[7]
Eccentricity (e)| 0.00 (assumed)
Inclination (i)| 84.40[7]°
Periastron epoch (T)| 53,501.5388±0.0013 MJD
Semi-amplitude (K1)
(primary)| 93.39±1.06 km/s
Semi-amplitude (K2)
(secondary)| 244.24±1.97 km/s
Details
Component 1
Mass| 2.179[7] M☉
Radius| 2.185[7] R☉
Luminosity| 19.0[7] L☉
Temperature| 8,150[7] K
Metallicity [Fe/H]| −0.08±0.09[8] dex
Age| 2.252[7] Gyr
Component 2
Mass| 0.739[7] M☉
Radius| 1.356[7] R☉
Luminosity| 3.85[7] L☉
Temperature| 6,915[7] K
Other designations

AG Vir, BD+13°2481, HD 104350, HIP 58605, SAO 99908, PPM 128717[9]

Database references
SIMBAD| data

AG Virginis is an eclipsing binary star system in the equatorial constellation of Virgo. With a maximum apparent visual magnitude of 8.51[3] it is too faint to be visible to the naked eye. The system is located at a distance of approximately 820 light years from the Sun based on parallax measurements.[2]

The variability of this system was first reported by P. Guthnick and R. Prager in 1929. R. S. Dugan determined the periodicity in 1933.[10] C. Blanco and F. Catalano in 1970 proposed that this is a semidetached binary where the primary component has filled its Roche lobe, thereby allowing mass transfer. They noted that the orbital period appeared to vary slightly with a ~40 year cycle,[11] which could be explained by a third component.[12] In 1986, J. Kaluzny produced a model for the light curve which suggested this is instead a contact binary. Multiple observers noted a permanent asymmetry to the light curve, with the primary minimum appearing distorted. A localized "hot spot" hypothesis was proposed to explain this feature.[13]

This is a close binary system with an orbital period of 15.4 hours. It is classified as a W Ursae Majoris variable,[6] which means the components are in near contact with each other and their mutual gravitational influence is distorting their shapes. The components are separated by just 4.5 times the radius of the Sun, and the orbital plane is inclined at an angle of 84.4° to the line of sight from the Earth.[7] This causes the two stars to eclipse each other during every orbit. The net visual brightness decreases by 0.58 in magnitude during the primary eclipse and by 0.45 during the secondary eclipse.[14]

The combined spectrum of the system has a varying stellar classification in the range of A7V-A9V,[4] matching an A-type main-sequence star. The primary component has 2.2 times the mass and radius of the Sun, while the secondary has 74% of the Sun's mass and 136% of the radius of the Sun.[7]

## References

1. ↑ "ASAS All Star Catalogue". The All Sky Automated Survey. http://www.astrouw.edu.pl/asas/?page=aasc.
2. ↑ 2.0 2.1 2.2 2.3 2.4 Brown, A. G. A. (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics 649: A1. doi:10.1051/0004-6361/202039657. Bibcode: 2021A&A...649A...1G. Gaia EDR3 record for this source at VizieR.
3. ↑ 3.0 3.1 3.2 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A.
4. ↑ 4.0 4.1 Hill, G. et al. (1975), "MK Classifications of some Northern Hemisphere Binary Systems", Memoirs of the Royal Astronomical Society 79: 131, Bibcode: 1975MmRAS..79..131H.
5. ↑ Samus, N. N. et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports, 5.1 61 (1): 80–88, doi:10.1134/S1063772917010085, Bibcode: 2017ARep...61...80S.
6. ↑ 6.0 6.1 Pribulla, Theodor et al. (August 2006), "Radial Velocity Studies of Close Binary Stars. XI.", The Astronomical Journal 132 (2): 769–780, doi:10.1086/505536, Bibcode: 2006AJ....132..769P.
7. ↑ 7.00 7.01 7.02 7.03 7.04 7.05 7.06 7.07 7.08 7.09 7.10 7.11 7.12 Latković, Olivera et al. (May 2021), "Statistics of 700 Individually Studied W UMa Stars", The Astrophysical Journal Supplement Series 254 (1): 18, doi:10.3847/1538-4365/abeb23, 10, Bibcode: 2021ApJS..254...10L.
8. ↑ Rucinski, Slavek M. et al. (September 2013), "Spectroscopic Metallicity Determinations for W UMa-type Binary Stars", The Astronomical Journal 146 (3): 20, doi:10.1088/0004-6256/146/3/70, 70, Bibcode: 2013AJ....146...70R.
9. ↑ "AG Vir". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=AG+Vir.
10. ↑ Binnendijk, L. (October 1969), "The light variation and orbital elements of AG Virginis", Astronomical Journal 74: 1024–1031, doi:10.1086/110898, Bibcode: 1969AJ.....74.1024B.
11. ↑ Blanco, C.; Catalano, F. (1970), "Light curve and elements of AG Vir", Memorie della Società Astronomia Italiana 41: p. 343, Bibcode: 1970MmSAI..41..343B.
12. ↑ Avvakumova, E. A. et al. (2014), "Observations of two unusual eclipsing binaries, FN Cam and AG Vir", Baltic Astronomy 23 (3–4): 255–259, doi:10.1515/astro-2017-0188, Bibcode: 2014BaltA..23..255A.
13. ↑ Kaluzny, J. (1986), "Contact binaries with components in poor thermal contact. IV. AG Virginis", Acta Astronomica 36: 121–129, Bibcode: 1986AcA....36..121K.
14. ↑ Avvakumova, E. A. et al. (October 2013), "Eclipsing variables: Catalogue and classification", Astronomische Nachrichten 334 (8): 860, doi:10.1002/asna.201311942, Bibcode: 2013AN....334..860A.

## Further reading

* Pribulla, T. et al. (July 2011), "O'Connell effect in early-type contact binaries: du Boo and AG Vir", Astronomische Nachrichten 332 (6): 607, doi:10.1002/asna.201111569, Bibcode: 2011AN....332..607P.
* Kim, Ho-Il et al. (December 2005), "A Spectroscopic Study of the Close Binary AG Virginis", Journal of Astronomy and Space Sciences 22 (4): 353–362, doi:10.5140/JASS.2005.22.4.353, Bibcode: 2005JASS...22..353K.
* Hobart, M. A. et al. (November 1998), "Character of the O-C Variation of Four W UMa Type Stars: AW UMa, AP Leo, AG VIR and AH Vir", Astrophysics and Space Science 260 (3): 375–388, doi:10.1023/A:1001726821949, Bibcode: 1998Ap&SS.260..375H.
* Djurašević, Gojko (August 1993), "An Analysis of Close Binaries Based on Photometric Measurements - Part Four - an Interpretation of CB Lightcurve Ag-Virginis by Using the Inverse-Problem Method", Astrophysics and Space Science 206 (1): 119–127, doi:10.1007/BF00658388, Bibcode: 1993Ap&SS.206..119D.
* Bell, S. A. et al. (December 1990), "Spots on AG Virginis - paradigm or panacea?", Monthly Notices of the Royal Astronomical Society 247: 632, Bibcode: 1990MNRAS.247..632B.
* Michaels, E. J. (June 1988), "AG Virginis: New Times of Minima and Period Study", Information Bulletin on Variable Stars 3202: 1, Bibcode: 1988IBVS.3202....1M.
* Niarchos, P. G. (August 1985), "Photoelectric light curves and elements of AG Virginis", Astronomy and Astrophysics Supplement Series 61: 313–318, Bibcode: 1985A&AS...61..313N.
* Hill, Graham; Barnes, Jeannette V. (June 1972), "A Spectroscopic Study of AG Virginis", Publications of the Astronomical Society of the Pacific 84 (499): 382, doi:10.1086/129298, Bibcode: 1972PASP...84..382H.

* v
* t
* e

Virgo constellation

Stars
(list)|

| Bayer|

* α (Spica)
* β (Zavijava)
* γ (Porrima)
* δ (Minelauva)
* ε (Vindemiatrix)
* ζ (Heze)
* η (Zaniah)
* θ
* ι (Syrma)
* κ (Kang)
* λ (Khambalia)
* μ
* ν
* ξ
* ο
* π
* ρ
* σ
* τ
* υ
* φ (Elgafar)
* χ
* ψ
* ω

|

Flamsteed|

* 4 (A1)
* 6 (A2)
* 7 (b)
* 10
* 11
* 12
* 13
* 14
* 16 (c)
* 17
* 20
* 21 (q)
* 25 (f)
* 27
* 28
* 31 (d1)
* 32 (d2)
* 33
* 34
* 35
* 37
* 38
* 39
* 41
* 44 (k)
* 46
* 48
* 49
* 50
* 53
* 54
* 55
* 56
* 57
* 58
* 59 (e)
* 61
* 62
* 63
* 64
* 65
* 66
* 68 (i)
* 69
* 70
* 71
* 72
* 73
* 74 (l)
* 75
* 76 (h)
* 77
* 78 (o)
* 80
* 81
* 82 (m)
* 83
* 84
* 85
* 86
* 87
* 88
* 89
* 90 (p)
* 92
* 94
* 95
* 96
* 97
* 103
* 104
* 106
* 108
* 109
* 110
* 1 Ser (M)
* 2 Ser

Variable|

* R
* S
* W
* RS
* RT
* SS
* ST
* SW
* TW
* TY
* UU
* UV
* UW
* UY
* XX
* AG
* AH
* AL
* AW
* AX
* AZ
* BB
* BF
* BH
* BK
* CE
* CS
* CU
* CX
* DK
* DL
* DM
* DT
* EP
* EQ
* ET
* FF
* FG
* FO
* FS
* FT
* FW
* GL
* GK
* GR
* HS
* HT
* HU
* HV
* HW
* IM
* IN
* IP
* IQ
* IS
* IV
* LN
* NN
* NY
* OU
* PP
* PX
* QS
* QZ

HR|

* 4478
* 4484
* 4510
* 4533
* 4544
* 4580
* 4587
* 4591
* 4598
* 4613
* 4657
* 4722
* 4741
* 4770
* 4772
* 4805
* 4837
* 4856
* 4877
* 4896
* 4901
* 4935
* 4957 (g)
* 4959
* 4960
* 4986
* 5013
* 5014
* 5031
* 5033
* 5037
* 5053
* 5059
* 5078
* 5086
* 5106 (y)
* 5114
* 5178
* 5183
* 5205
* 5233
* 5258
* 5272
* 5275
* 5276
* 5277
* 5283
* 5307
* 5317
* 5322
* 5332
* 5341
* 5342
* 5344
* 5353
* 5368
* 5384
* 5392
* 5418
* 5424
* 5496
* 5536
* 5584
* 5631

HD|

* 102195
* 102329
* 104078
* 104755
* 106038
* 106252
* 106270
* 106515
* 107148
* 107794
* 109271
* 112495
* 114783
* 116429
* 122577
* 124973
* 125490
* 125612
* 126614
* 128563
* 130322
* 133600

Other|

* EC 14012-1446
* G 64-12
* HAT-P-26
* K2-19
* PG 1159-035
* PG 1323-086
* PG 1325+101
* PSR B1257+12 (Lich)
* Ross 128
* SDSS J121209.31+013627.7
* SDSS J1229+1122
* ULAS J133553.45+113005.2
* WASP-16
* WASP-24
* WASP-37
* WASP-39 (Malmok)
* WASP-40/HAT-P-27
* WD 1145+017
* Wolf 424
* Wolf 485A
* Wolf 489

Star
clusters|

| Open|

* NGC 5634

|

Globular|

* HVGC-1
* Koposov I

Nebulae|

| Planetary|

* Abell 36

|

Galaxies|

| Messier|

* 49
* 58
* 59
* 60
* 61
* 84
* 86
* 87
* 89
* 90
* 104 (Sombrero Galaxy)

|

NGC|

* 3776
* 3817
* 3818
* 3833
* 3843
* 3848
* 3849
* 3852
* 3863
* 3876
* 3907
* 3907B
* 3914
* 3915
* 3952
* 3976
* 3976A
* 3979
* 4006
* 4012
* 4029
* 4030
* 4043
* 4044
* 4045
* 4045A
* 4058
* 4063
* 4067
* 4073
* 4075
* 4077
* 4079
* 4082
* 4083
* 4107
* 4116
* 4119
* 4123
* 4129
* 4139
* 4164
* 4165
* 4168
* 4176
* 4178
* 4179
* 4180
* 4191
* 4193
* 4197
* 4200
* 4201
* 4202
* 4206
* 4207
* 4215
* 4216
* 4223
* 4224
* 4233
* 4234
* 4235
* 4240
* 4241
* 4246
* 4247
* 4249
* 4252
* 4255
* 4257
* 4259
* 4260
* 4261
* 4264
* 4266
* 4267
* 4268
* 4269
* 4270
* 4273
* 4276
* 4277
* 4279
* 4281
* 4282
* 4285
* 4287
* 4289
* 4292
* 4292A
* 4294
* 4296
* 4297
* 4299
* 4300
* 4301
* 4305
* 4306
* 4307
* 4309
* 4309A
* 4313
* 4316
* 4318
* 4320
* 4324
* 4326
* 4330
* 4333
* 4334
* 4339
* 4341
* 4342
* 4343
* 4348
* 4351
* 4352
* 4353
* 4356
* 4360
* 4365
* 4366
* 4368
* 4370
* 4371
* 4376
* 4378
* 4380
* 4385
* 4387
* 4388
* 4390
* 4402
* 4403
* 4404
* 4410
* 4411
* 4412
* 4413
* 4415
* 4416
* 4417
* 4418
* 4420
* 4422
* 4423
* 4424
* 4425
* 4428
* 4429
* 4430
* 4431
* 4432
* 4433
* 4434
* 4436
* 4440
* 4442
* 4445
* 4451
* 4452
* 4453
* 4454
* 4457
* 4458
* 4461
* 4464
* 4465
* 4466
* 4467
* 4469
* 4470
* 4476
* 4478
* 4480
* 4482
* 4483
* 4484
* 4486A
* 4486B
* 4487
* 4488
* 4491
* 4492
* 4493
* 4496
* 4496B
* 4497
* 4503
* 4504
* 4517
* 4517A
* 4518
* 4518B
* 4519
* 4519A
* 4520
* 4522
* 4526
* 4527
* 4528
* 4531
* 4532
* 4533
* 4535
* 4535A
* 4536
* 4538
* 4541
* 4543
* 4544
* 4546
* 4550
* 4551
* 4564
* 4567
* 4568
* 4570
* 4576
* 4577
* 4578
* 4580
* 4581
* 4584
* 4586
* 4587
* 4588
* 4592
* 4593
* 4596
* 4597
* 4598
* 4599
* 4600
* 4602
* 4604
* 4606
* 4607
* 4608
* 4612
* 4620
* 4623
* 4626
* 4628
* 4629
* 4630
* 4632
* 4636
* 4637
* 4638
* 4639
* 4640
* 4640B
* 4641
* 4642
* 4643
* 4747 ([[Arp 116]])
* 4653
* 4654
* 4658
* 4660
* 4663
* 4664
* 4666
* 4668
* 4671
* 4674
* 4678
* 4680
* 4682
* 4684
* 4688
* 4690
* 4691
* 4694
* 4697
* 4698
* 4699
* 4700
* 4701
* 4703
* 4705
* 4708
* 4713
* 4716
* 4717
* 4718
* 4720
* 4731
* 4731A
* 4733
* 4734
* 4739
* 4742
* 4746
* 4753
* 4754
* 4757
* 4759A
* 4760
* 4761
* 4762
* 4764
* 4765
* 4766
* 4770
* 4771
* 4772
* 4773
* 4775
* 4777
* 4778
* 4779
* 4780
* 4780A
* 4781
* 4784
* 4786
* 4790
* 4791
* 4795
* 4796
* 4799
* 4803
* 4808
* 4809
* 4810
* 4813
* 4818
* 4820
* 4822
* 4823
* 4825
* 4829
* 4830
* 4836
* 4838
* 4843
* 4845
* 4847
* 4855
* 4856
* 4862
* 4863
* 4866
* 4877
* 4878
* 4880
* 4885
* 4887
* 4888
* 4890
* 4897
* 4899
* 4900
* 4902
* 4904
* 4915
* 4918
* 4920
* 4924
* 4925
* 4928
* 4933
* 4933C
* 4939
* 4941
* 4942
* 4948
* 4948A
* 4951
* 4958
* 4969
* 4975
* 4981
* 4984
* 4989
* 4990
* 4991
* 4992
* 4995
* 4996
* 4997
* 4999
* 5006
* 5010
* 5013
* 5015
* 5017
* 5018
* 5019
* 5020
* 5022
* 5027
* 5028
* 5030
* 5031
* 5035
* 5036
* 5037
* 5038
* 5039
* 5044
* 5046
* 5047
* 5049
* 5050
* 5054
* 5058
* 5059
* 5060
* 5066
* 5068
* 5071
* 5072
* 5073
* 5075
* 5076
* 5077
* 5079
* 5080
* 5084
* 5087
* 5088
* 5094
* 5095
* 5097
* 5099
* 5104
* 5105
* 5106
* 5111
* 5115
* 5118
* 5119
* 5122
* 5125
* 5129
* 5130
* 5132
* 5133
* 5134
* 5136
* 5137
* 5146
* 5147
* 5148
* 5159
* 5165
* 5167
* 5170
* 5171
* 5174
* 5176
* 5177
* 5178
* 5179
* 5181
* 5183
* 5184
* 5185
* 5186
* 5191
* 5192
* 5196
* 5197
* 5202
* 5203
* 5207
* 5208
* 5209
* 5210
* 5211
* 5212
* 5213
* 5221
* 5222
* 5224
* 5226
* 5227
* 5230
* 5231
* 5232
* 5235
* 5241
* 5245
* 5246
* 5247
* 5252
* 5254
* 5261
* 5270
* 5285
* 5300
* 5306
* 5324
* 5327
* 5329
* 5331
* 5334
* 5335
* 5338
* 5339
* 5343
* 5345
* 5348
* 5356
* 5360
* 5363
* 5364
* 5366
* 5369
* 5373
* 5374
* 5382
* 5384
* 5386
* 5387
* 5392
* 5400
* 5420
* 5442
* 5468
* 5470
* 5472
* 5476
* 5478
* 5491A
* 5491B
* 5493
* 5496
* 5501
* 5506
* 5507
* 5510
* 5521
* 5534
* 5537
* 5549
* 5551
* 5552
* 5554
* 5555
* 5560
* 5563
* 5566
* 5569
* 5573
* 5574
* 5575
* 5576
* 5577
* 5584
* 5599
* 5604
* 5618
* 5619
* 5619C
* 5636
* 5638
* 5645
* 5652
* 5661
* 5668
* 5674
* 5679
* 5679A
* 5679C
* 5679D
* 5680
* 5690
* 5691
* 5692
* 5701
* 5705
* 5713
* 5718
* 5719
* 5725
* 5733
* 5738
* 5740
* 5746
* 5750
* 5765
* 5765B
* 5770
* 5774
* 5775
* 5776
* 5806
* 5811
* 5813
* 5814
* 5831
* 5838
* 5839
* 5845
* 5846
* 5846A
* 5847
* 5848
* 5850
* 5854
* 5855
* 5864
* 5865
* 5869

Other|

* A1689-zD1
* Abell 1835 IR1916
* Arp 240 (NGC 5257 and NGC 5258)
* Arp 271 (NGC 5426 and NGC 5427)
* BR 1202-0725
* 3C 273
* 3C 279
* 3C 298
* 4C 04.42
* Eyes Galaxies
* GR 8
* IC 3258
* IC 3328
* IRAS 12212+0305
* IRAS 13197−1627
* M60-UCD1
* Markarian 50
* Markarian 1318
* PG 1216+069
* PG 1244+026
* PG 1254+047
* PG 1307+085
* PG 1416−129
* PG 1426+015
* PKS 1148-001
* PKS 1167+014
* PKS 1217+023
* PKS 1229−021
* PKS 1302−102
* PKS 1335−127
* PKS 1402+044
* PKS 1405−076
* QSO B1208+1011
* QSO B1243−072
* QSO B1246−057
* QSO B1331+170
* RXJ1242−11
* SMM J14011+0252
* UM 448
* UM 461
* UM 462

Galaxy
clusters|

* Abell 1644
* Abell 1650
* Abell 1651
* Abell 1689
* Abell 1750
* Abell 1835
* Abell 2029
* Abell 2147
* HCG 62
* MKW 4
* NGC 5044 group
* RX J1347.5−1145
* Virgo Cluster

Other|

* GRB 930131
* GRB 030328
* GRB 050408
* GRB 050801
* GRB 080310
* North Polar Spur
* SN 1960F
* SN 1981B
* SN 1990B
* SN 1990N
* SN 1991T
* SN 1991bg
* SN 1994D
* SN 1999br
* SN 2002cx
* SN 2007bi
* U1.11

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