HD 19467

HD 19467
Observation data
Epoch J2000.0      Equinox ICRS
Constellation Eridanus
Right ascension 03h 07m 18.575s
Declination −13° 45′ 42.42″
Apparent magnitude (V) 6.97
Characteristics
Evolutionary stage main sequence
Spectral type G3 V + T5.5±1.0
B−V color index 0.645±0.010
Astrometry
Radial velocity (Rv)6.953±0.0003 km/s
Proper motion (μ) RA: −8.694 mas/yr
Dec.: −260.642 mas/yr
Parallax (π)31.2191±0.024 mas
Distance104.47 ± 0.08 ly
(32.03 ± 0.02 pc)
Absolute magnitude (MV)4.52
Orbit
PrimaryHD 19467 A
SecondaryHD 19467 B
Period (P)319+114
−72 yr
Semi-major axis (a)46.9+11.0
−7.4 AU
Eccentricity (e)0.50+0.10
−0.08
Inclination (i)134.7+12.0
−6.9°
Longitude of the node (Ω)134.8±4.5°
Periastron epoch (T)2,486,750+1,523
−1,890 BJD
Argument of periastron (ω)
(secondary)		280+14
−18°
Details
HD 19467 A
Mass0.96±0.02 M☉
Radius1.20±0.03 R☉
Luminosity1.42±0.06 L☉
Surface gravity (log g)4.28±0.04 cgs
Temperature5747±40 K
Metallicity [Fe/H]−0.11±0.01 dex
Rotation29.53±0.16 d
Rotational velocity (v sin i)1.6±0.5 km/s
Age9.4±0.9 Gyr
HD 19467 B
Mass71.6+5.3
−4.6 MJup
Radius0.790+0.012
−0.013 RJup
Luminosity10−5.09+0.03
−0.04 L☉
Surface gravity (log g)5.45±0.06 cgs
Temperature1,081+28
−29 K
Metallicity [Fe/H]−0.15±0.02 dex
Other designations
BD−14°604, FK5 1087, GJ 3200, HD 19467, HIP 14501, SAO 148780, PPM 212460
Database references
SIMBADdata

HD 19467 is a star with an orbiting brown dwarf companion in the equatorial constellation of Eridanus. It has an apparent visual magnitude of 6.97, which is a challenge to view with the naked eye. The system is located at a distance of 104.5 light years based on parallax measurements, and is drifting further away with a radial velocity of 7 km/s. It has a high proper motion, traversing the celestial sphere at an angular rate of 0.258 arcsec yr−1. Based on the motion and chemical abundances of this star it has been considered a likely member of the Wolf 630 group of co-moving stars, although its age estimate is inconsistent with that assignment.

The spectrum of HD 19467 presents as a G-type main-sequence star with a stellar classification of G3 V. It has been identified as a solar twin based on the similarity of its physical properties to the Sun. This is an older star, with age estimates range from 5.4 up to 10.1 billion years, depending on the study. It is considered a thin disk star, which should theoretically limit the age to no more than 8 billion years. The spin rate is correspondingly low with a rotation period of 29.5 days. Based on the abundance of iron, the metallicity is lower than solar. The level of magnetic activity in the star's chromosphere as well as X-ray emission are at most below the equivalent level in the Sun.

Brown dwarf

In 2014, a survey team announced the discovery of a brown dwarf in orbit around HD 19467. The presence of an low-mass companion was indicated via an acceleration trend in radial velocity time series data collected between 1996 and 2021. The object was then directly imaged using the NIRC-2 instrument at the Keck Observatory. Designated HD 19467 B, it was located at an angular separation of 1.6″ from the host star. Astrometric observations taken over a 1.1 year period demonstrated that the object is clearly associated with HD 19467 A, having a similar parallax and proper motion. The radial velocity data indicated a minimum mass of 51.9+3.6
−4.3 MJ, with a brightness and colors matching a T-dwarf.

The spectrum of this object was taken at the Palomar Observatory, finding a spectral type of T5.5±1. It was measured as having an effective temperature of 978 K and, like the host star, a sub-solar metallicity. Orbital analysis was used to infer a mass of 65.4 MJ, which is near the substellar mass boundary. It has a highly eccentric orbit with period estimates ranging from 320 to 420 years, depending on the study.

See also

References

  1. 1 2 3 4 5 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015. XHIP record for this object at VizieR.
  2. 1 2 3 4 5 6 Vallenari, A.; et al. (Gaia collaboration) (2023), "Gaia Data Release 3. Summary of the content and survey properties", Astronomy and Astrophysics, 674: A1, arXiv:2208.00211, Bibcode:2023A&A...674A...1G, doi:10.1051/0004-6361/202243940, S2CID 244398875. Gaia DR3 record for this source at VizieR.
  3. 1 2 3 4 5 6 Brandt, G. Mirek; et al. (December 2021), "Improved Dynamical Masses for Six Brown Dwarf Companions Using Hipparcos and Gaia EDR3", The Astronomical Journal, 162 (6), id. 301, arXiv:2109.07525, Bibcode:2021AJ....162..301B, doi:10.3847/1538-3881/ac273e.
  4. 1 2 Houk, N.; Smith-Moore, M. (1988), Michigan Catalogue of Two-dimensional Spectral Types for the HD Stars. Declinations -26°.0 to -12°.0, vol. 4, University of Michigan, Ann Arbor, MI: Department of Astronomy, Bibcode:1988mcts.book.....H.
  5. 1 2 Soubiran, C.; et al. (2018), "Gaia Data Release 2. The catalogue of radial velocity standard stars", Astronomy and Astrophysics, 616: A7, arXiv:1804.09370, Bibcode:2018A&A...616A...7S, doi:10.1051/0004-6361/201832795, S2CID 52952408.
  6. 1 2 Hoch, Kielan K. W.; et al. (October 2024), "JWST-TST High Contrast: Spectroscopic Characterization of the Benchmark Brown Dwarf HD 19467 B with the NIRSpec Integral Field Spectrograph", The Astronomical Journal, 168 (4): 187, arXiv:2408.03830, doi:10.3847/1538-3881/ad6cd3, ISSN 0004-6256.
  7. 1 2 3 4 5 6 7 8 Maire, A. -L.; et al. (July 2020), "Orbital and spectral characterization of the benchmark T-type brown dwarf HD 19467B", Astronomy & Astrophysics, 639, id. A47, arXiv:2005.10312, Bibcode:2020A&A...639A..47M, doi:10.1051/0004-6361/202037984.
  8. 1 2 3 4 5 6 Greenbaum, Alexandra Z.; et al. (March 2023), "First Observations of the Brown Dwarf HD 19467 B with JWST", The Astrophysical Journal, 945 (2): 126, arXiv:2301.11455, Bibcode:2023ApJ...945..126G, doi:10.3847/1538-4357/acb68b.
  9. 1 2 3 4 5 Picos, Darío González; Post, Tessa van der; Regt, Sam de; Ruffio, Jean-Baptiste; Grasser, Natalie; Snellen, Ignas (2026-05-04), "JWST high-contrast spectroscopy with speckle modelling: Atmospheric retrievals of the T dwarf companion HD 19467 B", Astronomy and Astrophysics, arXiv:2605.02769.
  10. 1 2 Wood, Charlotte M.; et al. (March 2019), "Benchmarking Substellar Evolutionary Models Using New Age Estimates for HD 4747 B and HD 19467 B", The Astrophysical Journal, 873 (1): 83, arXiv:1901.03687, Bibcode:2019ApJ...873...83W, doi:10.3847/1538-4357/aafe01.
  11. ↑ "HD 19467", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2024-01-17.
  12. ↑ Luyten, W. J. (June 1995), "NLTT Catalogue (Luyten, 1979)", VizieR Online Data Catalog, Bibcode:1995yCat.1098....0L.
  13. ↑ Bubar, Eric J.; King, Jeremy R. (August 2010), "Spectroscopic Abundances and Membership in the Wolf 630 Moving Group", The Astronomical Journal, 140 (2): 293–318, arXiv:1005.1205, Bibcode:2010AJ....140..293B, doi:10.1088/0004-6256/140/2/293.
  14. ↑ Ramírez, I.; et al. (December 2014), "The Solar Twin Planet Search. I. Fundamental parameters of the stellar sample", Astronomy & Astrophysics, 572, id. A48, arXiv:1408.4130, Bibcode:2014A&A...572A..48R, doi:10.1051/0004-6361/201424244.
  15. ↑ Fuhrmann, Klaus; Chini, Rolf (March 2021), "On ancient solar-type stars - II", Monthly Notices of the Royal Astronomical Society, 501 (4): 4903–4916, Bibcode:2021MNRAS.501.4903F, doi:10.1093/mnras/staa3942.
  16. ↑ Crepp, Justin R.; et al. (January 2014), "The TRENDS High-contrast Imaging Survey. V. Discovery of an Old and Cold Benchmark T-dwarf Orbiting the Nearby G-star HD 19467", The Astrophysical Journal, 781 (1): 29, arXiv:1311.0280, Bibcode:2014ApJ...781...29C, doi:10.1088/0004-637X/781/1/29.
  17. ↑ Crepp, Justin R.; et al. (January 2015), "Direct Spectrum of the Benchmark T Dwarf HD 19467 B", The Astrophysical Journal Letters, 798 (2), id. L43, arXiv:1412.6101, Bibcode:2015ApJ...798L..43C, doi:10.1088/2041-8205/798/2/L43.

Further reading