HD 197027

Short description: Star in the constellation Capricornus

HD 197027

HIP 102152
Credit: ESO/Digitized Sky Survey 2

Observation data
Epoch J2000.0 Equinox (celestial coordinates)
Constellation | Capricornus
Right ascension |  20h 41m 54.6336s[1]
Declination | −27° 12′ 57.4154″[1]
Apparent magnitude (V) | 9.15±0.02[2]
Characteristics
Spectral type | G3 V[3]
U−B color index | +0.30[4]
B−V color index | +0.65[2]
Astrometry
Radial velocity (Rv)| −43.9±0.3[5] km/s
Proper motion (μ)|  RA: +175.628[1] mas/yr
Dec.: −15.593[1] mas/yr
Parallax (π)| 12.7715 ± 0.0164[1] mas
Distance| 255.4 ± 0.3 ly
(78.3 ± 0.1 pc)
Absolute magnitude (MV)| 4.74[6]
Details
Mass| 0.97[7] M☉
Radius| 1.08+0.07−0.05[8] R☉
Luminosity| 1.19[6] L☉
Surface gravity (log g)| 4.40±0.02[9] cgs
Temperature| 5718±5[9] K
Metallicity [Fe/H]| −0.020±0.005[9] dex
Rotational velocity (v sin i)| 1.78±0.12[9] km/s
Age| 6.92±0.69[9] Gyr
Other designations

CD−27°14976, CPD−27°7079, HD 197027, HIP 102152, SAO 189585[10]

Database references
SIMBAD| data

HD 197027 (HIP 102152) is a star in the constellation Capricornus. It has an apparent magnitude of 9.15,[2] making it readily visible through a telescope but not to the naked eye. The object is located at a distance of 255 light years but is approaching the Solar System with a heliocentric radial velocity of −44 km/s.[5]

HD 197027 has a stellar classification of G3 V, indicating that it is an ordinary G-type main-sequence star like the Sun. It has only 97% the mass of the Sun[7] but 108% of its radius.[8] It shines at 119% the luminosity of the Sun[6] from its photosphere at an effective temperature of 5,718 K,[9] similar to the Sun's 5,778 K. HD 197027's metallicity – elements heavier than helium – is similar to the Sun.[9] At an older age of 6.92 billion years, it spins with a projected rotational velocity of about 2 km/s.[9]

Since its measured properties of this star are very similar to those of the Sun, it has been considered a candidate older solar twin.[11] The abundances of 21 elements overall are more similar to the Sun than any other known solar twin. [citation needed] Its Iron Abundance is -0.03 with an error value of 0.02 Fe/H. (The value comes from the Hipparcos Extended Catalog.)[12]

## Age

The age of HD 197027, here annotated as HIP 102152, shown relative to the Sun, the younger solar twin 18 Scorpii and the formation of the Milky Way

## References

1. ↑ 1.0 1.1 1.2 1.3 1.4 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.
2. ↑ 2.0 2.1 2.2 Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P. et al. (March 2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics 355: L27–L30. ISSN 0004-6361. Bibcode: 2000A&A...355L..27H.
3. ↑ Houk, N. (1982). Michigan Catalogue of Two-dimensional Spectral Types for the HD stars. Volume_3. Declinations -40_ƒ0 to -26_ƒ0.. Bibcode: 1982mcts.book.....H.
4. ↑ Paunzen, E. (May 2022). "Catalogue of stars measured in the Geneva seven-colour photometric system". Astronomy & Astrophysics 661: A89. doi:10.1051/0004-6361/202142355. ISSN 0004-6361. Bibcode: 2022A&A...661A..89P.
5. ↑ 5.0 5.1 Gontcharov, G. A. (November 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. ISSN 1063-7737. Bibcode: 2006AstL...32..759G.
6. ↑ 6.0 6.1 6.2 Anderson, E.; Francis, Ch. (May 2012). "XHIP: An extended hipparcos compilation" (in en). Astronomy Letters 38 (5): 331–346. doi:10.1134/S1063773712050015. ISSN 1063-7737. Bibcode: 2012AstL...38..331A.
7. ↑ 7.0 7.1 Talawanda R. Monroe (Aug 2013). "High Precision Abundances of the Old Solar Twin HIP 102152: Insights on Li Depletion from the Oldest Sun". Astrophysical Journal Letters 774 (2): L32. doi:10.1088/2041-8205/774/2/l32. Bibcode: 2013ApJ...774L..32M.
8. ↑ 8.0 8.1 Stassun, Keivan G. et al. (9 September 2019). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal 158 (4): 138. doi:10.3847/1538-3881/ab3467. ISSN 0004-6256. Bibcode: 2019AJ....158..138S.
9. ↑ 9.0 9.1 9.2 9.3 9.4 9.5 9.6 9.7 dos Santos, Leonardo A. et al. (August 2016), "The Solar Twin Planet Search. IV. The Sun as a typical rotator and evidence for a new rotational braking law for Sun-like stars", Astronomy & Astrophysics 592: 8, doi:10.1051/0004-6361/201628558, A156, Bibcode: 2016A&A...592A.156D.
10. ↑ "HD 197027". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+197027.
11. ↑ ESO, The life cycle of a Sun-like star (annotated), from European Southern Observatory, 28 August 2013
12. ↑ "HD 197027 Star Distance, Age, Colour and other Facts - Universe Guide" (in en-us). 10 January 2024. https://www.universeguide.com/star/102152/hd197027.

## External links

* Oldest Solar Twin Identified
* HIGH PRECISION ABUNDANCES OF THE OLD SOLAR TWIN HIP 102152: INSIGHTS ON LI DEPLETION FROM THE OLDEST SUN
* Oldest Solar Twin Identified

* v
* t
* e

Constellation of Capricornus

* List of stars in Capricornus
* Capricornus in Chinese astronomy

Stars|

| Bayer|

* α1 (Prima Giedi)
* α2 (Algedi)
* β1 (Dabih)
* β2
* γ (Nashira)
* δ (Deneb Algedi)
* ε
* ζ
* η
* θ
* ι
* κ
* λ
* μ
* ν (Alshat)
* ξ1
* ξ2
* ο1
* ο2
* π
* ρ
* σ
* τ1
* τ2
* υ
* φ
* χ
* ψ
* ω

|

Flamsteed|

* 3
* 4
* 17
* 19
* 20
* 21
* 24 (A)
* 26
* 27
* 29
* 30
* 31
* 33
* 35
* 36 (b)
* 37
* 38
* 41
* 42
* 44
* 45
* 46 (c)
* 47 (c2)
* 50

Variable|

* R
* RS
* RV
* TW
* YZ
* AD
* AS
* AT
* AV
* AZ
* BE
* BW

HR|

* 7722
* 7788
* 7819
* 7825
* 7837
* 7842
* 7845
* 7855
* 7865
* 7877
* 7898
* 7905
* 7910
* 7931
* 7961
* 7964
* 7989
* 8013
* 8018
* 8045
* 8083
* 8122
* 8172
* 8184
* 8235
* 8247
* 8273
* 8293
* 8337
* 8340
* 8346

HD|

* 197027
* 202206
* 203607
* 204313
* 204941

Other|

* LP 816-60
* PSR B2045-16
* Wolf 922

| Exoplanets|

* HD 202206 b
* c
* HD 204313 b
* PSO J318.5−22

|

| Star clusters|

* Messier 30
* Palomar 12

|

Galaxies|

| NGC|

* 6897
* 6898
* 6903
* 6907
* 6908
* 6912
* 6924
* 6931
* 6936
* 6986
* 6993
* 7016
* 7017
* 7018
* 7019
* 7030
* 7035
* 7035A
* 7073
* 7103
* 7104
* 7105
* 7131

|

Other|

* IC 1337
* PHL 1811
* PKS 2126-158
* PKS 2128-12
* PKS 2135-147
* PKS 2155-152

| Galaxy clusters|

* HCG 87
* MS 2137.3-2353

|

| Astronomical events|

* GRB 060607

|

Category

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