HD 197027

HD 197027

HIP 102152
Credit: ESO/Digitized Sky Survey 2
Observation data
Epoch J2000      Equinox J2000
Constellation Capricornus
Right ascension 20:41:45.632h[1]
Declination −27:12:57.414°[1]
Apparent magnitude (V) 9.18
Characteristics
Spectral type G3V[1]
B−V color index +0.65[1]
Astrometry
Radial velocity (Rv)-44.3[1] km/s
Proper motion (μ) RA: +172.91[1] mas/yr
Dec.: -15.41[1] mas/yr
Parallax (π)12.84 ± 0.97[1] mas
Distance250 ± 20 ly
(78 ± 6 pc)
Absolute magnitude (MV)4.72
Details
Mass0.97[2] M☉
Surface gravity (log g)4.40±0.02[3] cgs
Temperature5718±5[3] K
Metallicity [Fe/H]−0.020±0.005[3] dex
Rotational velocity (v sin i)1.78±0.12[3] km/s
Age6.92±0.69[3] Gyr
Other designations
HIP 102152, PPM 271498, SAO 189585.[1]
Database references
SIMBADdata

HD 197027 (HIP 102152) is a star in the constellation Capricornus that is located about 250 light years from the Sun.

The measured properties of this star are very similar to those of the Sun, making it a candidate older solar twin.[4] The abundances of 21 elements overall are more similar to the Sun than any other known solar twin. Additionally, the effective temperature, surface gravity, and microturbulence are nearly identical to the Sun's. However, it is significantly older than the Sun, being approximately 3.6 billion years older than the Sun, at 8.2 Billion years old. The fact that the abundances are so similar to the Sun's suggests that it is a potential candidate for hosting terrestrial type planets.

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

Sun comparison

This chart compares the sun to HD 197027/HIP 102152.

Identifier J2000 Coordinates[1] Distance[1]
(ly)		 Stellar
Class[1]		 Temperature
(K)		 Metallicity
(dex)		 Age
(Gyr)		 Notes
Right ascension Declination
Sun — — 0.00 G2V 5,778 +0.00 4.6 [5]
HD 197027 [6] 20h 41m 54.6s –27° 12′ 57″ 250 G3V 5,723 −0.013 8.2 [7]

An exact solar twin would be a G2V star with a 5,778K temperature, be 4.6 billion years old, with the correct metallicity and a 0.1% solar luminosity variation.[8] Stars with an age of 4.6 billion years are at the most stable state. Proper metallicity and size are also very important to low luminosity variation.[9][10][11]

References

  1. 1 2 3 4 5 6 7 8 9 10 11 12 "HD 197027". SIMBAD. Centre de Données astronomiques de Strasbourg. Retrieved 2013-09-07.
  2. ↑ Talawanda R. Monroe; et al. (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. Bibcode:2013ApJ...774L..32M. arXiv:1308.5744 Freely accessible. doi:10.1088/2041-8205/774/2/l32.
  3. 1 2 3 4 5 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, Bibcode:2016A&A...592A.156D, doi:10.1051/0004-6361/201628558, A156.
  4. ↑ ESO, The life cycle of a Sun-like star (annotated), from European Southern Observatory, 28 August 2013
  5. ↑ Williams, D.R. (2004). "Sun Fact Sheet". NASA. Retrieved 2009-06-23.
  6. ↑ HIP 102152 at SIMBAD - Ids - Bibliography - Image.
  7. ↑ Monroe, T. R.;; et al. (2013). "High Precision Abundances of the Old Solar Twin HIP 102152: Insights on Li Depletion from the Oldest Sun". The Astrophysical Journal Letters. 774 (2): 22. Bibcode:2013ApJ...774L..32M. arXiv:1308.5744 Freely accessible. doi:10.1088/2041-8205/774/2/L32.
  8. ↑ NASA, Science News, Solar Variability and Terrestrial Climate, Jan. 8, 2013
  9. ↑ University of Nebraska-Lincoln astronomy education group, Stellar Luminosity Calculator
  10. ↑ National Center for Atmospheric Research, The Effects of Solar Variability on Earth's Climate, 2012 Report
  11. ↑ Most of Earth’s twins aren’t identical, or even close!, by Ethan on June 5, 2013


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