TT Cygni

Short description: Star in the constellation Cygnus

TT Cygni

250px
A light curve for TT Cygni, plotted from Hipparcos data[1]

Observation data
Equinox J2000.0]] (ICRS)
Constellation | Cygnus
Right ascension |  19h 40m 57.01599s[2]
Declination | +32° 37′ 05.7555″[2]
Apparent magnitude (V) | 7.26 - 8.0[3]
Characteristics
Evolutionary stage | AGB[4]
Spectral type | C5,4e(N3e)[3]
B−V color index | +2.917±0.073[5]
Variable type | SRb[6]
Astrometry
Radial velocity (Rv)| −49.0±3.1[5] km/s
Proper motion (μ)|  RA: −5.178[2] mas/yr
Dec.: −1.832[2] mas/yr
Parallax (π)| 1.4908 ± 0.0368[2] mas
Distance| 2,190 ± 50 ly
(670 ± 20 pc)
Absolute magnitude (MV)| −1.297 (var.)[7]
Details
Mass| 3.4[8] M☉
Radius| 166[9] R☉
Luminosity| 2,735[10] L☉
Surface gravity (log g)| −0.4[10] cgs
Temperature| 3,200[10] K
Metallicity [Fe/H]| −9.49[8] dex
Other designations

TT Cyg, BD+32°3522, HD 186047, HIP 96836, SAO 68688[11]

Database references
SIMBAD| data

TT Cygni is a carbon star located 561 parsecs (1,830 ly) away in the northern constellation of Cygnus. It is classified as a semiregular variable of subtype SRb that ranges in brightness from magnitude 7.26 down to 8.0 with a period of 118 days.[3] This object is called a carbon star because it has a high ratio of carbon to oxygen in its surface layers. The carbon was produced by helium fusion, dredged up from inside the star by deep convection triggered by a flash from the helium shell.

In 1898 it was announced that Louisa Dennison Wells had discovered that the star, then known as BD +32°3522, is a variable star.[12] It was listed with its variable star designation, TT Cygni, in Annie Jump Cannon's 1907 work Second Catalog of Variable Stars.[13]

A thin spherical shell around the star, about half a light year across, was emitted 7,000 years ago.[14] It was first detected from its carbon monoxide emission and has a mass around four thousandths M☉, of which about a tenth is dust. The dust is thought to be mostly amorphous carbon.[10]

## References

1. ↑ "Hipparcos Tools Interactive Data Access". ESA. https://www.cosmos.esa.int/web/hipparcos/interactive-data-access.
2. ↑ 2.0 2.1 2.2 2.3 2.4 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G. Gaia DR2 record for this source at VizieR.
3. ↑ 3.0 3.1 3.2 "TT Cygni". AAVSO. https://www.aavso.org/vsx/index.php?view=detail.top&oid=10947. Retrieved 2021-02-04.
4. ↑ Maercker, M.; De Beck, E.; Khouri, T.; Vlemmings, W. H. T.; Gustafsson, J.; Olofsson, H.; Tafoya, D.; Kerschbaum, F. et al. (2024). "Probing the dynamical and kinematical structures of detached shells around AGB stars". Astronomy and Astrophysics 687: A112. doi:10.1051/0004-6361/202449643. Bibcode: 2024A&A...687A.112M.
5. ↑ 5.0 5.1 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A.
6. ↑ 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.
7. ↑ Gontcharov, G. A. (2011). "The red giant branch in the Tycho-2 catalogue". Astronomy Letters 37 (10): 707–717. doi:10.1134/S1063773711090040. Bibcode: 2011AstL...37..707G.
8. ↑ 8.0 8.1 Khalatyan, A.; Anders, F.; Chiappini, C.; Queiroz, A. B. A.; Nepal, S.; Dal Ponte, M.; Jordi, C.; Guiglion, G. et al. (2024). "Transferring spectroscopic stellar labels to 217 million Gaia DR3 XP stars with SHBoost". Astronomy and Astrophysics 691: A98. doi:10.1051/0004-6361/202451427. Bibcode: 2024A&A...691A..98K.
9. ↑ McDonald, I.; Zijlstra, A. A.; Watson, R. A. (2017). "Fundamental parameters and infrared excesses of Tycho–Gaia stars". Monthly Notices of the Royal Astronomical Society 471 (1): 770–791. doi:10.1093/mnras/stx1433. Bibcode: 2017MNRAS.471..770M.
10. ↑ 10.0 10.1 10.2 10.3 Groenewegen, M. A. T. (2012). "An extension of the DUSTY radiative transfer code and an application to OH 26.5 and TT Cygni". Astronomy and Astrophysics 543: A36. doi:10.1051/0004-6361/201218965. Bibcode: 2012A&A...543A..36G.
11. ↑ "TT Cyg". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=TT+Cyg.
12. ↑ Pickering, E. C.; Bailey, S. I.; Fleming, W. P.; Leland, E. F.; Wells, L. D. (March 1898). "Variable star clusters. New variable stars". Astrophysical Journal 7: 208–211. doi:10.1086/140457. Bibcode: 1898ApJ.....7..208P.
13. ↑ Cannon, Annie J. (1907). "Second catalogue of variable stars". Annals of Harvard College Observatory 55: 1–94. Bibcode: 1907AnHar..55....1C.
14. ↑ Olofsson, H. et al. (January 2000). "A high-resolution study of episodic mass loss from the carbon star TT Cygni". Astronomy and Astrophysics 353: 583–597. Bibcode: 2000A&A...353..583O.

* v
* t
* e

Constellation of Cygnus

* List of stars in Cygnus

Stars|

| Bayer|

* α (Deneb)
* β (Albireo)
* γ (Sadr)
* δ (Fawaris)
* ε (Aljanah)
* ζ
* η
* θ
* ι1
* ι2
* κ
* λ
* μ
* ν
* ξ
* π1 (Azelfafage)
* π2
* ρ
* σ
* τ
* υ
* φ
* χ
* ψ
* ω1
* ω2
* P
* Q

|

Flamsteed|

* 2
* 4
* 8
* 9
* 14
* 15
* 16 (c)
* 17
* 20 (d)
* 22
* 23
* 26 (e)
* 27 (b1)
* 28 (b2)
* 29 (b3)
* 30
* 31
* 32
* 33
* 35
* 39
* 41
* 47
* 52
* 55
* 56
* 57
* 59 (f1)
* 61
* 63 (f2)
* 68 (A)
* 71 (g)
* 72
* 74
* 75

Variable|

* R
* T
* W
* RW
* SS
* TT
* BC
* BI
* CH
* KY
* V404
* V476
* V1057
* V1143
* V1191
* V1489
* V1500
* V1668
* V1974
* V2513

HR|

* 7633
* 7912
* 8193

HD|

* 185269
* 185435
* 187123
* 188753
* 191806

Gliese|

* 777
* 806
* 1245

Kepler|

* 5
* 6
* 11
* 15
* 16
* 17
* 18
* 22
* 23
* 27
* 28
* 29
* 31
* 32
* 33
* 34
* 35
* 36
* 39
* 40
* 41
* 42
* 43
* 44
* 45
* 47
* 51
* 56
* 61
* 66
* 67
* 68
* 69
* 70
* 78
* 80
* 84
* 86
* 89
* 107
* 182
* 186
* 223
* 371
* 419
* 432
* 451
* 452
* 1229
* 1520
* 1625

Other|

* AFGL 2591
* BD+40° 4210
* BD+43 3654
* Cygnus OB2 #8A
* Cygnus OB2 #12
* Cygnus X-1
* Cygnus X-3
* G 208-44
* G 208-45
* HAT-P-7
* HAT-P-11
* HAT-P-17
* KELT-9
* KIC 8462852
* KIC 9832227
* KIC 11026764
* KOI-74
* KOI-81
* KOI-256
* KPD 1930+2752
* MWC 349
* N6946-BH1
* NML Cygni
* PH1
* PSR J2032+4127
* W75N(B)-VLA2
* WISE J2000+3629
* WR 134
* WR 135
* WR 136
* WR 137
* WR 140
* WR 142
* WR 147
* WR 148

Former|

* 3

Star
clusters|

| Association|

* Cygnus OB2
* Cygnus OB7

|

Open|

* DR 6
* IC 5146
* Messier 29
* Messier 39
* NGC 6811
* NGC 6819
* NGC 6834
* NGC 6866
* NGC 6871
* NGC 6910

Molecular
clouds|

* Cygnus X (including DR 21)

Nebulae|

| Dark|

* Barnard 146
* Barnard 147
* IC 5146
* L1014

|

H II|

* NGC 6914
* North America Nebula
* Pelican Nebula
* Sadr Region
* Sh2-101
* Sh2-106

Planetary|

* Abell 78
* Egg Nebula
* IRAS 19475+3119
* Kronberger 61
* M1-92
* NGC 6826
* NGC 6881
* NGC 6884
* NGC 7008
* NGC 7026
* NGC 7027
* NGC 7048
* Soap Bubble Nebula

WR|

* Crescent Nebula

SNR|

* Cygnus Loop (including Veil Nebula)

Galaxies|

| NGC|

* 6801
* 6946
* 7013

|

Other|

* 3C 438
* Cygnus A

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