HD 9986

HD 9986
Observation data
Epoch J2000      Equinox J2000
Constellation Pisces
Right ascension 01h 37m 40.87964s[1]
Declination +12° 04′ 42.1742″[1]
Characteristics
Spectral type G5V [2]
Details
Mass1.02 [2] M☉
Temperature5749 [3] K
Metallicity [Fe/H]+0.09 ± 0.04 [2] dex
Age4.3 [4] Gyr
Other designations
HD 9986, HIP 7585, TYCHO-2 2000 TYC 624-723-1, USNO-A2.0, USNO-A2 0975-00368208
Database references
SIMBADdata
Data sources:
Hipparcos Catalogue


HD 9986 is a Sun-like star 84 light years (25.733 parsecs) from the Sun. HD 9986 is a G-type star and a near solar twin[5][6] A speckle survey of G-dwarfs by Elliott P. Horch in 2002 noted that HD 9986 may not be non-single star.[3]


Sun comparison

This chart compares the sun to HD 9986.

Identifier J2000 Coordinates Distance
(ly)		 Stellar
Class		 Temperature
(K)		 Metallicity
(dex)		 Age
(Gyr)		 Notes
Right ascension Declination
Sun — — 0.00 G2V 5,778 +0.00 4.6 [7]
HD 9986 [8] 01h 37m 40.9s +12° 04′ 42″ 84 G5V 5749 +0.09 4.3 [9][4]

To date no solar twin with an exact match as that of the Sun has been found, however, there are some stars that come very close to being identical to that of the Sun, and are such considered solar twins by the majority of the public. 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.[10] 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. [11][12][13]

Morgan-Keenan spectral classification of stars. Most common star type in the universe are M-dwarfs, 76%. The sun is a 4.6 billion year-old G-class (G2V) star and is more massive than 95% of all stars. Only 7.6% are G-class stars


References

  1. 1 2 "HD 9986 – Star". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved July 13, 2016.
  2. 1 2 3 "Stellar magnetism: empirical trends with age and rotation," (PDF). Royal Astronomical Society. Cornell University - Astronomy & Astrophysics manuscript. Retrieved July 13, 2016.
  3. 1 2 "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 parsecs: The Northern Sample I.," (PDF). cds.cern.ch. Cornell University - Astronomy & Astrophysics manuscript. Retrieved July 13, 2016.
  4. 1 2 "A photometric and spectroscopic survey of solar twin stars within 50 parsecs of the Sun page 7 & 11 & 17, December 31, 2013" (PDF). arxiv. Cornell University - Astronomy & Astrophysics manuscript. Retrieved July 13, 2016.
  5. ↑ "HD 9986". Retrieved 18 April 2016.
  6. ↑ Skymap, HIP 7585
  7. ↑ Williams, D.R. (2004). "Sun Fact Sheet". NASA. Retrieved 2009-06-23.
  8. ↑ HD 9986 at SIMBAD - Ids - Bibliography - Image.
  9. ↑ Porto de Mello, G. F.; da Silva, R.; da Silva, L.; de Nader, R. V. (March 2014). "A photometric and spectroscopic survey of solar twin stars within 50 parsecs of the Sun; I. Atmospheric parameters and color similarity to the Sun". Astronomy and Astrophysics. 563: A52. arXiv:1312.7571Freely accessible. Bibcode:2014A&A...563A..52P. doi:10.1051/0004-6361/201322277.
  10. ↑ NASA, Science News, Solar Variability and Terrestrial Climate, Jan. 8, 2013
  11. ↑ University of Nebraska-Lincoln astronomy education group, Stellar Luminosity Calculator
  12. ↑ National Center for Atmospheric Research, The Effects of Solar Variability on Earth's Climate, 2012 Report
  13. ↑ Most of Earth’s twins aren’t identical, or even close!, by Ethan on June 5, 2013



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