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HD 222925

Elements detected in HD 222925 totalling 65 with 42 coming from the r-process (31 ≤ Z ≤ 92) . Elements with no long-lived isotopes are indicated using the light gray font. [1]
Observation data
Epoch J2000.00       Equinox J2000.00
Constellation Tucana
Right ascension 23h 45m 17.607s [2]
Declination −61° 54′ 42.84″ [2]
Apparent magnitude (V) 9.03 [3]
Characteristics
Evolutionary stage horizontal branch
Spectral type F8 Sr Eu [4] (ApSrEu) [5]
Astrometry
Radial velocity (Rv)−38.9±0.6 [6] km/s
Proper motion (μ) RA: 143.803 [2]  mas/ yr
Dec.: −99.109 [2]  mas/ yr
Parallax (π)2.2202 ± 0.0117  mas [2]
Distance1,469 ± 8  ly
(450 ± 2  pc)
Details
Mass0.75±0.20 [6]  M☉
Radius6 [7]  R☉
Luminosity43 [4]  L☉
Surface gravity (log g)2.54±0.17 [1]  cgs
Temperature5,636±103 [1]  K
Metallicity [Fe/H]−1.47±0.08 [6]  dex
Other designations
CD−62°1462, HD 222925, HIP 117168
Database references
SIMBAD data

HD 222925 is a horizontal branch star about 1,470 light years away in the southern constellation Tucana. It is magnitude 9, far below naked-eye visibility. It is an Ap star, a type of chemically peculiar star with an over-abundance of certain metals in its spectrum.

HD 222925 has been referred to as the 'gold standard star' by the media. [8] In 2022, astronomers from the University of Michigan identified 65 elements in the star (including gold), a turning point to help the scientific community understand the rapid neutron capture process. [9] The elements were produced in a massive supernova or a merger of neutron stars early in the universe, and it was ejected into space where it later reformed into the current star. [10]

Gallery

  • Wavelength for each element detected by atomic number with each spectral line represented as a dot. A gap between ≈3145 Å and ≈3330 Å reflecting an atmospheric cutoff between STIS and MIKE spectra.[1]
    Wavelength for each element detected by atomic number with each spectral line represented as a dot. A gap between ≈3145 Å and ≈3330 Å reflecting an atmospheric cutoff between STIS and MIKE spectra. [1]
  • This mosaic shows two GHOST spectra of HD 222925.[11]
    This mosaic shows two GHOST spectra of HD 222925. [11]


References

  1. ^ a b c d Roederer, Ian U.; Lawler, James E.; Den Hartog, Elizabeth A.; Placco, Vinicius M.; Surman, Rebecca; Beers, Timothy C.; Ezzeddine, Rana; Frebel, Anna; Hansen, Terese T.; Hattori, Kohei; Holmbeck, Erika M.; Sakari, Charli M. (2022). "The R-process Alliance: A Nearly Complete R-process Abundance Template Derived from Ultraviolet Spectroscopy of the R-process-enhanced Metal-poor Star HD 222925". The Astrophysical Journal Supplement Series. 260 (2): 27. arXiv: 2205.03426. Bibcode: 2022ApJS..260...27R. doi: 10.3847/1538-4365/ac5cbc. S2CID  248571656.
  2. ^ a b c d e Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv: 2012.01533. Bibcode: 2021A&A...649A...1G. doi: 10.1051/0004-6361/202039657. S2CID  227254300. (Erratum:  doi: 10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  3. ^ Bailer-Jones, C. A. L.; et al. (2011). "Bayesian inference of stellar parameters and interstellar extinction using parallaxes and multiband photometry". Monthly Notices of the Royal Astronomical Society. 411 (1): 435–452. arXiv: 1009.2766. Bibcode: 2011MNRAS.411..435B. doi: 10.1111/j.1365-2966.2010.17699.x. S2CID  30425562.
  4. ^ a b Cunha, M. S.; et al. (2019). "Rotation and pulsation in Ap stars: First light results from TESS sectors 1 and 2". Monthly Notices of the Royal Astronomical Society. 487 (3): 3523. arXiv: 1906.01111. Bibcode: 2019MNRAS.487.3523C. doi: 10.1093/mnras/stz1332.
  5. ^ Houk, Nancy (1975). Michigan catalogue of two-dimensional spectral types for the HD stars. Vol. 1. Ann Arbor, Michigan: Dept. of Astronomy, University of Michigan. Bibcode: 1975mcts.book.....H.
  6. ^ a b c Roederer, Ian U.; Sakari, Charli M.; Placco, Vinicius M.; Beers, Timothy C.; Ezzeddine, Rana; Frebel, Anna; Hansen, Terese T. (2018). "The R-Process Alliance: A Comprehensive Abundance Analysis of HD 222925, a Metal-poor Star with an Extreme R-process Enhancement of [Eu/H] = -0.14". The Astrophysical Journal. 865 (2): 129. arXiv: 1808.09469. Bibcode: 2018ApJ...865..129R. doi: 10.3847/1538-4357/aadd92. S2CID  119046070.
  7. ^ Cruzalèbes, P.; Petrov, R. G.; Robbe-Dubois, S.; Varga, J.; Burtscher, L.; Allouche, F.; Berio, P.; Hofmann, K. H.; Hron, J.; Jaffe, W.; Lagarde, S.; Lopez, B.; Matter, A.; Meilland, A.; Meisenheimer, K.; Millour, F.; Schertl, D. (2019). "A catalogue of stellar diameters and fluxes for mid-infrared interferometry". Monthly Notices of the Royal Astronomical Society. 490 (3): 3158–3176. arXiv: 1910.00542. Bibcode: 2019MNRAS.490.3158C. doi: 10.1093/mnras/stz2803. S2CID  203610229.
  8. ^ "Astronomers find 'gold standard' star in Milky Way". University of Michigan News. 2022-05-10. Retrieved 2022-05-18.
  9. ^ Sherburne, Morgan; Michigan, University of. "Astronomers find 'gold standard' star in Milky Way". phys.org. Retrieved 2022-05-18.
  10. ^ Science, Carnegie (2022-05-13). "Astronomers find 'gold standard' star in Milky Way". Carnegie Institution for Science. Archived from the original on 2022-05-13. Retrieved 2022-05-18.
  11. ^ "Gemini's GHOST Captures Exquisite First Light Observations of a Bright, Chemically Rich Star". Retrieved 16 December 2022.

External links

Retrieved from " https://en.wikipedia.org/?title=HD_222925&oldid=1230348230"

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