HD 206893

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HD 206893
Observation data
Epoch J2000.0       Equinox J2000.0
Constellation Capricornus [1]
Right ascension 21h 45m 21.905s [2]
Declination −12° 47′ 00.06″ [2]
Apparent magnitude  (V)6.69 [1]
Characteristics
Evolutionary stage Main sequence
Spectral type F5V [3]
B−V color index 0.439±0.007 [1]
Astrometry
Radial velocity (Rv)−12.45±0.59 [4] km/s
Proper motion (μ)RA: 94.112 mas/yr [2]
Dec.: −0.463 mas/yr [2]
Parallax (π)24.5275±0.0354  mas [2]
Distance 133.0 ± 0.2  ly
(40.77 ± 0.06  pc)
Absolute magnitude  (MV)3.77 [1]
Details
Mass 1.32±0.02 [5]   M☉
Radius 1.26±0.02 [5]   R☉
Luminosity 2.74 [1]   L☉
Surface gravity (log g)4.27±0.15 [6]   cgs
Temperature 6,617±46 [6]   K
Metallicity [Fe/H]−0.07±0.27 [7]   dex
Rotation 0.996±0.003 d [5]
Rotational velocity (v sin i)32±2 [5]  km/s
Age 155±15 [8]   Myr
Other designations
BD−13°6008, GC  30461, HD  206893, HIP  107412, SAO  164627, PPM  239301 [9]
Database references
SIMBAD data

HD 206893 is a young star with a planetary system located in the southern constellation of Capricornus, the sea goat. It has an apparent visual magnitude of 6.69, [1] which is faint enough that it is a challenge to view with the naked eye. Based on parallax measurements, this star is located at a distance of 133  light years from the Sun. It is drifting closer with a heliocentric radial velocity of −12.5 km/s. [4] From the location and velocity of this star, there is a 61.1% probability it is a member of the Argus moving group. [10]

Contents

Observations

The stellar classification of HD 206893 is F5V, [3] matching an F-type main-sequence star that is generating energy through hydrogen fusion at its core. Its metallicity – the abundance of elements more massive than helium – is similar to that in the Sun. [7] Due to uncertainties in the age of young F-type dwarfs, the age of the star is not well constrained but is most probably in the range of 3 to 300 million years. [6] Assuming a likely age of about 250 million years, a stellar model of HD 206893 yields a mass 32% greater than the Sun and a radius 26% broader. As a young star, it has a relatively high rate of spin with a projected rotational velocity of 32 km/s. [5]

Data collected during the IRAS mission showed an infrared excess from this star. [11] The presence of a debris disk was confirmed with data from the ISO and Spitzer space missions. [12] Observations with the Atacama Large Millimeter Array show a wide disk extending from inside a radius of 34  au from the host star out to 158±6 au. There is evidence for a density minimum at around 70 au from the star, which most likely a gap with a width of 13+5
−7 au starting at an inner radius of 73+5
−9 au. [13] This opening is suggestive of having been cleared by an planetary-mass companion. [14]

Planetary system

In 2015, direct imaging of the debris disk with the VLT-SPHERE revealed a substellar companion at a physical separation of 10.4 au from the host star. The detection was confirmed ten months later, ruling out a background object. [15] Designated HD 206893 B, the body appears very red in hue, most likely due to nearby dust. It is orbiting inside the inner edge of the debris disk, at an angle of 20.8°+13.6°
−11.2° to the plane of the disk. [16] The estimated mass of this companion is in the range of 12–78  MJ , and it is most likely an L-type brown dwarf. Perturbation by this object may be causing collisions within the debris disk. [17]

In 2023, long-term monitoring of radial velocity variations by the star indicated the presence of an additional inner companion. Designated HD 206893 c, this exoplanet has a mass of 12.7+1.2
−1.0 MJ and an orbital separation of 3.53+0.08
−0.06 au, which gives an orbital period of approximately 5.7 years. The mass of HD 206893 c is located near the deuterium–burning limit, which may be impacting the evolution of the object. The precise astrometry of this system provides a more robust age estimate of 155±15 million years. [8]

The HD 206893 planetary system [8]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
c11.5+2.4
−2.2  MJ 		3.68+0.12
−0.09		2,100 d (5.7 yr)0.36+0.05
−0.06		—1.46+0.18
−0.06  RJ
B26.2+3.7
−3.6  MJ 		9.7+0.8
−0.4		9,500 d (26 yr)0.13+0.06
−0.09		—1.25±0.02  RJ
debris disk≤ 34–158±6 [13] AU ——
d [14] (candidate)0.9 MJ ~74—0.14+0.05
−0.04		——

References

  1. 1 2 3 4 5 6 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, S2CID   119257644.
  2. 1 2 3 4 5 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 Gray, R. O.; et al. (2006), "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 pc–The Southern Sample", The Astronomical Journal, 132 (1): 161–170, arXiv: astro-ph/0603770 , Bibcode:2006AJ....132..161G, doi:10.1086/504637, S2CID   119476992.
  4. 1 2 Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics . 616. A1. arXiv: 1804.09365 . Bibcode: 2018A&A...616A...1G . doi: 10.1051/0004-6361/201833051 . Gaia DR2 record for this source at VizieR.
  5. 1 2 3 4 5 Delorme, P.; et al. (December 2017), "In-depth study of moderately young but extremely red, very dusty substellar companion HD 206893B⋆", Astronomy & Astrophysics, 608, id. A79, arXiv: 1709.00349 , Bibcode:2017A&A...608A..79D, doi:10.1051/0004-6361/201731145.
  6. 1 2 3 Baburaj, Aneesh; et al. (February 2025), "A High-resolution Spectroscopic Survey of Directly Imaged Companion Hosts. I. Determination of Diagnostic Stellar Abundances for Planet Formation and Composition", The Astronomical Journal, 169 (2), id. 55, arXiv: 2409.14239 , Bibcode:2025AJ....169...55B, doi: 10.3847/1538-3881/ad8dfc .
  7. 1 2 Saffe, C.; et al. (October 2008), "Spectroscopic metallicities of Vega-like stars", Astronomy and Astrophysics, 490 (1): 297–305, arXiv: 0805.3936 , Bibcode:2008A&A...490..297S, doi:10.1051/0004-6361:200810260.
  8. 1 2 3 Hinkley, S.; et al. (March 2023), "Direct discovery of the inner exoplanet in the HD206893 system. Evidence for deuterium burning in a planetary-mass companion", Astronomy & Astrophysics, 671, id. L5, arXiv: 2208.04867 , Bibcode:2023A&A...671L...5H, doi:10.1051/0004-6361/202244727.
  9. ↑ "HD 206893", SIMBAD , Centre de données astronomiques de Strasbourg , retrieved 2025-02-13.
  10. ↑ Ward-Duong, K.; et al. (January 2021), "Gemini Planet Imager Spectroscopy of the Dusty Substellar Companion HD 206893 B", The Astronomical Journal, 161 (1), id. 5, arXiv: 2010.10546 , Bibcode:2021AJ....161....5W, doi: 10.3847/1538-3881/abc263 .
  11. ↑ Zuckerman, B.; Song, Inseok (March 2004), "Dusty Debris Disks as Signposts of Planets: Implications for Spitzer Space Telescope", The Astrophysical Journal, 603 (2): 738–743, arXiv: astro-ph/0311546 , Bibcode:2004ApJ...603..738Z, doi:10.1086/381700.
  12. ↑ Moór, A.; et al. (June 2006), "Nearby Debris Disk Systems with High Fractional Luminosity Reconsidered", The Astrophysical Journal, 644 (1): 525–542, arXiv: astro-ph/0603729 , Bibcode:2006ApJ...644..525M, doi:10.1086/503381.
  13. 1 2 Nederlander, A.; et al. (January 2021), "Resolving Structure in the Debris Disk around HD 206893 with ALMA", Bulletin of the American Astronomical Society, 53 (1), id. 2021n1i325p06, Bibcode:2021AAS...23732506N.
  14. 1 2 Marino, S.; et al. (October 2020), "Insights into the planetary dynamics of HD 206893 with ALMA", Monthly Notices of the Royal Astronomical Society, 498 (1): 1319–1334, arXiv: 2010.12582 , Bibcode:2020MNRAS.498.1319M, doi: 10.1093/mnras/staa2386 .
  15. ↑ Milli, J.; et al. (January 2017), "Discovery of a low-mass companion inside the debris ring surrounding the F5V star HD 206893", Astronomy & Astrophysics, 597, id. L2, arXiv: 1612.00333 , Bibcode:2017A&A...597L...2M, doi:10.1051/0004-6361/201629908.
  16. ↑ Kammerer, J.; et al. (August 2021), "GRAVITY K-band spectroscopy of HD 206893 B. Brown dwarf or exoplanet", Astronomy & Astrophysics, 652, id. A57, arXiv: 2106.08249 , Bibcode:2021A&A...652A..57K, doi:10.1051/0004-6361/202140749.
  17. ↑ Meshkat, Tiffany; et al. (August 2021), "Characterization of HD 206893 B from Near- to Thermal-infrared", The Astrophysical Journal, 917 (2): 62, Bibcode:2021ApJ...917...62M, doi: 10.3847/1538-4357/ac09ed .

Further reading

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