Astronomy:HD 19467
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Eridanus[1] |
| Right ascension | 03h 07m 18.575s[2] |
| Declination | −13° 45′ 42.42″[2] |
| Apparent magnitude (V) | 6.97[1] |
| Characteristics | |
| Evolutionary stage | main sequence[3] |
| Spectral type | G3 V[4] + T5.5±1.0[3] |
| B−V color index | 0.645±0.010[1] |
| Astrometry | |
| Radial velocity (Rv) | 6.953±0.0003[5] km/s |
| Proper motion (μ) | RA: −8.694[2] mas/yr Dec.: −260.642[2] mas/yr |
| Parallax (π) | 31.2191 ± 0.024[2] mas |
| Distance | 104.47 ± 0.08 ly (32.03 ± 0.02 pc) |
| Absolute magnitude (MV) | 4.52[1] |
| Orbit[6] | |
| Primary | HD 19467 A |
| Companion | HD 19467 B |
| Period (P) | 398+95−93 yr |
| Semi-major axis (a) | 54±9 astronomical unit|AU |
| Eccentricity (e) | 0.56±0.09 |
| Inclination (i) | 129.8+8.1−5.1° |
| Longitude of the node (Ω) | 134.8±4.5° |
| Periastron epoch (T) | 2,512,264+12,428 −12,637 BJD |
| Argument of periastron (ω) (secondary) | 64.2+5.5−6.3° |
| Details | |
| HD 19467 A | |
| Mass | 0.96±0.02[7] M☉ |
| Radius | 1.20±0.03[7] R☉ |
| Luminosity | 1.42±0.06[7] L☉ |
| Surface gravity (log g) | 4.28±0.04[7] cgs |
| Temperature | 5,747±40[7] K |
| Metallicity [Fe/H] | −0.11±0.01[6] dex |
| Rotation | 29.53±0.16 d[6] |
| Rotational velocity (v sin i) | 1.6±0.5[6] km/s |
| Age | 5.4+1.9 −1.3 Gyr[3] 10.06+1.16−0.82[8] Gyr |
| HD 19467 B | |
| Mass | 65.4+5.9−4.6[3] MJup |
| Luminosity | (6.49±0.98)×10−6[8] L☉ |
| Temperature | 978+20−43[9] K |
| Other designations | |
| Database references | |
| SIMBAD | data |
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,[1] 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,[2] and is drifting further away with a radial velocity of 7 km/s.[5] It has a high proper motion, traversing the celestial sphere at an angular rate of 0.258 arcsec yr−1.[11] 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.[12]
The spectrum of HD 19467 presents as a G-type main-sequence star with a stellar classification of G3 V.[4] It has been identified as a solar twin based on the similarity of its physical properties to the Sun.[13] This is an older star,[6] with age estimates range from 5.4[3] up to 10.1 billion years,[8] depending on the study. It is considered a thin disk star, which should theoretically limit the age to no more than 8 billion years.[6] The spin rate is correspondingly low with a rotation period of 29.5 days.[6] Based on the abundance of iron, the metallicity is lower than solar.[14][6] 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.[3]
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 Jupiter mass, with a brightness and colors matching a T-dwarf.[15]
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.[9] Orbital analysis was used to infer a mass of 65.4 Jupiter mass, 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.[3]
See also
- Scholz's Star – a star with a brown dwarf companion of similar mass to HD 19467 B[3]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A.
- ↑ 2.0 2.1 2.2 2.3 2.4 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 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, doi:10.3847/1538-3881/ac273e, Bibcode: 2021AJ....162..301B.
- ↑ 4.0 4.1 Houk, N.; Smith-Moore, M. (1988), Michigan Catalogue of Two-dimensional Spectral Types for the HD Stars. Declinations -26°.0 to -12°.0, 4, University of Michigan, Ann Arbor, MI: Department of Astronomy, Bibcode: 1988mcts.book.....H.
- ↑ 5.0 5.1 Soubiran, C. et al. (2018), "Gaia Data Release 2. The catalogue of radial velocity standard stars", Astronomy and Astrophysics 616: A7, doi:10.1051/0004-6361/201832795, Bibcode: 2018A&A...616A...7S.
- ↑ 6.0 6.1 6.2 6.3 6.4 6.5 6.6 6.7 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, doi:10.1051/0004-6361/202037984, Bibcode: 2020A&A...639A..47M.
- ↑ 7.0 7.1 7.2 7.3 7.4 Greenbaum, Alexandra Z. et al. (March 2023), "First Observations of the Brown Dwarf HD 19467 B with JWST", The Astrophysical Journal 945 (2): 126, doi:10.3847/1538-4357/acb68b, Bibcode: 2023ApJ...945..126G.
- ↑ 8.0 8.1 8.2 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, doi:10.3847/1538-4357/aafe01, Bibcode: 2019ApJ...873...83W.
- ↑ 9.0 9.1 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, doi:10.1088/2041-8205/798/2/L43, Bibcode: 2015ApJ...798L..43C.
- ↑ "HD 19467". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+19467.
- ↑ Luyten, W. J. (June 1995), "NLTT Catalogue (Luyten, 1979)", VizieR Online Data Catalog, Bibcode: 1995yCat.1098....0L.
- ↑ 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, doi:10.1088/0004-6256/140/2/293, Bibcode: 2010AJ....140..293B.
- ↑ Ramírez, I. et al. (December 2014), "The Solar Twin Planet Search. I. Fundamental parameters of the stellar sample", Astronomy & Astrophysics 572: id. A48, doi:10.1051/0004-6361/201424244, Bibcode: 2014A&A...572A..48R.
- ↑ Fuhrmann, Klaus; Chini, Rolf (March 2021), "On ancient solar-type stars - II", Monthly Notices of the Royal Astronomical Society 501 (4): 4903–4916, doi:10.1093/mnras/staa3942, Bibcode: 2021MNRAS.501.4903F.
- ↑ 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, doi:10.1088/0004-637X/781/1/29, Bibcode: 2014ApJ...781...29C.
Further reading
- Mesa, D. et al. (July 2020), "Characterizing brown dwarf companions with IRDIS long-slit spectroscopy: HD 1160 B and HD 19467 B", Monthly Notices of the Royal Astronomical Society 495 (4): 4279–4290, doi:10.1093/mnras/staa1444, Bibcode: 2020MNRAS.495.4279M.
- Wood, Charlotte et al. (January 2018), "Precise Ages for the Benchmark Brown Dwarfs HD 19467 B and HD 4747 B", American Astronomical Society, AAS Meeting #231 231: id. 450.05, Bibcode: 2018AAS...23145005W.
- Jensen-Clem, Rebecca et al. (April 2016), "Point Source Polarimetry with the Gemini Planet Imager: Sensitivity Characterization with T5.5 Dwarf Companion HD 19467 B", The Astrophysical Journal 820 (2): id. 111, doi:10.3847/0004-637X/820/2/111, Bibcode: 2016ApJ...820..111J.
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