TT Aquilae

Short description: Star in the constellation Aquila

TT Aquilae

250px
A visual band light curve for TT Aquilae, adapted from Kiss (1998)[1]

Observation data
Equinox J2000.0]] (ICRS)
Constellation | Aquila
Right ascension |  19h 08m 13.75081s[2]
Declination | +01° 17′ 55.1600″[2]
Apparent magnitude (V) | 6.52 - 7.65[3]
Characteristics
Spectral type | G0/2Ib[4] (F6-G5[3])
U−B color index | +0.638 - +1.601[5]
B−V color index | +0.932 - +1.637[5]
Variable type | δ Cep[3]
Astrometry
Radial velocity (Rv)| 3.00[6] km/s
Proper motion (μ)|  RA: +1.17[2] mas/yr
Dec.: −3.33[2] mas/yr
Parallax (π)| 0.18 ± 1.26[2] mas
Absolute magnitude (MV)| −4.26[7]
Details
Mass| 6.2 - 8.6[8] M☉
Radius| 83.8 - 100.5[9] R☉
Luminosity| 5,284[8] L☉
Surface gravity (log g)| 1.10 - 1.70[7] cgs
Temperature| 5,007 - 5,630[7] (- 6,200[10]) K
Metallicity| +0.10[7]
Other designations

TT Aql, HD 178359, HIP 93390, BD+01°3899, SAO 124305

Database references
SIMBAD| data
Data sources:
Hipparcos Catalogue,
CCDM (2002),
Bright Star Catalogue (5th rev. ed.)

TT Aquilae (TT Aql) is a Classical Cepheid (δ Cep) variable star in the constellation Aquila.

The visual apparent magnitude of TT Aql ranges from 6.52 to 7.65 over 13.7546 days.[3] The light curve is asymmetric, with the rise from minimum to maximum brightness only taking half the time of the fall from maximum to minimum.[11]

The announcement that the star's brightness varies was made in 1907 by Annie Jump Cannon. It had been observed on 506 photographs taken from May 22, 1888 through November 9, 1906, from which a period of 13.75 days had been derived.[12][13]

TT Aql is a yellow-white supergiant around five thousand times brighter than the sun. It pulsates and varies in temperature between about 5,000 K and 6,000 K,[10] and the spectral type varies between F6 and G5. The radius is 91.4 R☉ at maximum brightness, varying between 84 R☉ and 100 R☉ as the star pulsates.[9]

Cepheid masses can be estimated using Baade-Wesselink relations and this gives 8.6 M☉. The mass estimated by matching to evolutionary tracks is 7.7 M☉. The mass calculated by modelling the pulsations is 6.2 M☉. The discrepancies between the masses obtained by the different methods occurs for most Cepheid variables.[8]

## References

1. ↑ Kiss, Laszlo L. (July 1998). "A photometric and spectroscopic study of the brightest northern Cepheids - I. Observations". Monthly Notices of the Royal Astronomical Society 297 (3): 825. doi:10.1046/j.1365-8711.1998.01559.x. Bibcode: 1998MNRAS.297..825K.
2. ↑ 2.0 2.1 2.2 2.3 2.4 Van Leeuwen, F. (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.
3. ↑ 3.0 3.1 3.2 3.3 Samus, N. N. et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S 1. Bibcode: 2009yCat....102025S.
4. ↑ Houk, N.; Swift, C. (1999). "Michigan catalogue of two-dimensional spectral types for the HD Stars, Vol. 5". Michigan Spectral Survey 05: 0. Bibcode: 1999MSS...C05....0H.
5. ↑ 5.0 5.1 Berdnikov, L. N. (2008). "VizieR Online Data Catalog: Photoelectric observations of Cepheids in UBV(RI)c (Berdnikov, 2008)". VizieR On-line Data Catalog: II/285. Originally Published in: 2008yCat.2285....0B 2285. Bibcode: 2008yCat.2285....0B.
6. ↑ Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters 32 (11): 759–771. doi:10.1134/S1063773706110065. Bibcode: 2006AstL...32..759G.
7. ↑ 7.0 7.1 7.2 7.3 Kovtyukh, V. V.; Andrievsky, S. M.; Belik, S. I.; Luck, R. E. (2005). "Phase-dependent Variation of the Fundamental Parameters of Cepheids. II. Periods Longer than 10 Days". The Astronomical Journal 129 (1): 433–453. doi:10.1086/426339. Bibcode: 2005AJ....129..433K.
8. ↑ 8.0 8.1 8.2 Gieren, W. P. (1989). "Towards a reconciliation of Cepheid masses". Astronomy and Astrophysics 225: 381. Bibcode: 1989A&A...225..381G.
9. ↑ 9.0 9.1 Imbert, M. (1999). "Détermination des rayons de Céphéides. V. Vitesses radiales et dimensions de 22 Céphéides galactiques. Determination of the radii of Cepheids V. Radial velocities and dimensions of 22 galactic Cepheids". Astronomy and Astrophysics Supplement 140: 79–87. doi:10.1051/aas:1999515. Bibcode: 1999A&AS..140...79I.
10. ↑ 10.0 10.1 Luck, R. E.; Andrievsky, S. M.; Fokin, A.; Kovtyukh, V. V. (2008). "Phase-Dependent Variation of the Fundamental Parameters of Cepheids. Iv. S-CEPHEIDS". The Astronomical Journal 136 (1): 98. doi:10.1088/0004-6256/136/1/98. Bibcode: 2008AJ....136...98L.
11. ↑ Schaltenbrand, R.; Tammann, G. A. (1971). "The light curve parameters of photoelectrically observed galactic Cepheids". Astronomy and Astrophysics Supplement 4: 265. Bibcode: 1971A&AS....4..265S.
12. ↑ Cannon, A. J.; Pickering, E. C. (1907). "15 New Variable Stars in Harvard Maps Nos. 31 and 62". Harvard College Observatory Circular 129: 1–3. Bibcode: 1907HarCi.129....1C. https://articles.adsabs.harvard.edu/full/1907HarCi.129....1C. Retrieved 21 November 2024.
13. ↑ Jordan, F. C. (October 1919). "The color changes of certain variable stars of short period". Astrophysical Journal 50: 174–205. doi:10.1086/142495. Bibcode: 1919ApJ....50..174J. https://articles.adsabs.harvard.edu/pdf/1919ApJ....50..174J. Retrieved 21 November 2024.

## External links

* INTEGRAL-OMC catalogue

* v
* t
* e

Aquila constellation

Stars
(list)|

| Bayer|

* α (Altair)
* β (Alshain)
* γ (Tarazed)
* δ
* ε
* ζ (Okab)
* η
* θ (Tseen Foo)
* ι
* κ
* λ
* μ
* ν
* ξ (Libertas)
* ο
* π
* σ
* τ
* υ
* φ
* χ
* ψ
* ω1
* ω2

|

Flamsteed|

* 4
* 5
* 7
* 8
* 10
* 11
* 12 (i)
* 14 (g)
* 15 (h)
* 18
* 19
* 20
* 21
* 22
* 23
* 24
* 26 (f)
* 27 (d)
* 28 (A)
* 31 (b)
* 35 (c)
* 36 (e)
* 37 (k)
* 42
* 45
* 46
* 51
* 56
* 57
* 58
* 62
* 64
* 66
* 68
* 69
* 70
* 71 (l)
* 14 Sge
* 62 Ser

Variable|

* R
* U
* V
* W
* RR
* RT
* SZ
* TT
* UU
* VX
* AA
* CI
* DO
* EL
* FF
* FM
* FN
* KL
* KO
* KP
* OO
* QS
* QY
* V337
* V341
* V346
* V368
* V374
* V417
* V450
* V500
* V536
* V603
* V604
* V605
* V606
* V725
* V794
* V803
* V805
* V822
* V889
* V923
* V1182
* V1208
* V1229
* V1286
* V1291
* V1302
* V1315
* V1333
* V1339
* V1370
* V1379
* V1401 (64 Sgr)
* V1402
* V1412
* V1413
* V1419
* V1425
* V1427
* V1429
* V1432
* V1449
* V1472
* V1493
* V1494
* V1654
* V1663
* V1691
* V1703

HR|

* 7085
* 7099
* 7143
* 7163
* 7208
* 7214
* 7269
* 7288
* 7300
* 7307
* 7313
* 7325
* 7349
* 7353
* 7354
* 7389
* 7396
* 7397
* 7404
* 7407
* 7412
* 7432
* 7438
* 7449
* 7456
* 7471
* 7516
* 7541
* 7542
* 7559
* 7562
* 7569
* 7598
* 7599
* 7636
* 7637
* 7648
* 7681
* 7693
* 7700
* 7717
* 7768
* 7794
* 7803
* 7809
* 7878

HD|

* 179079
* 179218
* 182040
* 183263
* 184279
* 185966
* 186535
* 187734
* 190073
* 192086
* 192699
* 194263
* 195617

Gliese|

* Gliese 735
* Gliese 752

Other|

* AFGL 2298
* B335
* CoRoT-2
* CoRoT-3
* CoRoT-8
* GRS 1915+105
* 1H 1905+000
* J1953−1019
* LDS 678
* NSVS 14256825
* PSR B1853+01
* PSR B1955+09
* PSR B1913+16 (Hulse–Taylor)
* PSR B1915+13
* PSR B1916+14
* PSR B1929+10
* PSR B1933+16
* PSR J1846-0258
* PSR J1903+0327
* PSR J1951+1123
* SGR 1900+14
* SS 433
* 4U 1907+09
* VB 10
* W43A
* W51 e2
* W51 North
* W51 IRS 2
* WR 123

Former|

* ρ (Tso Ke)
* 1
* 2
* 3
* 6
* 9

Star
clusters|

| Open|

* NGC 6709
* NGC 6755
* NGC 6756
* NGC 6837

|

Globular|

* NGC 6749
* NGC 6760

Nebulae|

| Star-forming|

* G29.96-0.02
* G31.31+0.31
* G34.26+0.15
* G35.2-0.74
* G45.45+0.06
* W43
* W48
* W49
* W49A
* W49N
* W51
* W51A
* IRAS 19111+1048

|

Planetary|

* Abell 58
* Abell 70
* IC 4846
* Me 1-1
* NGC 6741
* NGC 6751
* NGC 6772
* NGC 6778
* NGC 6781
* NGC 6790
* NGC 6803
* NGC 6804
* NGC 6807
* NGC 6852
* Sh 2-71
* Vy 2-2

SNR|

* 3C 391
* 3C 396
* 3C 397
* Kes 75
* Kes 79
* W44
* W49B
* W50
* W51C

Galaxies|

| NGC|

* 6814
* 6821
* 6865
* 6900
* 6901
* 6906
* 6915
* 6922
* 6926
* 6929
* 6941

|

Other|

* 3C 403
* QSO B1937-1009

Other|

* Smith's Cloud

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