HD 7449
Observation data
Epoch J2000      Equinox J2000
Constellation Cetus
Right ascension 01h 14m 29.32229s[1]
Declination −05° 02′ 50.6148″[1]
Apparent magnitude (V) 7.50[2]
Characteristics
Spectral type F9.5V[2] + M4.5[3]
B−V color index 0.575±0.007[2]
Astrometry
Radial velocity (Rv)−19.60±0.13[1] km/s
Proper motion (μ) RA: −164.544±0.039 mas/yr[1]
Dec.: −134.382±0.028 mas/yr[1]
Parallax (π)25.9132 ± 0.0287 mas[1]
Distance125.9 ± 0.1 ly
(38.59 ± 0.04 pc)
Absolute magnitude (MV)4.55[2]
Orbit[4]
PrimaryHD 7449 A
CompanionHD 7449 B
Period (P)175.310+43.633
−34.380 yr
Semi-major axis (a)34.655+5.498
−4.781 AU
Eccentricity (e)0.301+0.084
−0.102
Inclination (i)68.400+4.103
−3.887°
Longitude of the node (Ω)325.935+2.865
−2.404°
Periastron epoch (T)2391480.709+12803.765
−15269.796
Argument of periastron (ω)
(secondary)		201.186+12.830
−13.166°
Semi-amplitude (K1)
(primary)		0.720525+0.043724
−0.029891 km/s
Details[5]
HD 7449 A
Mass1.05±0.02 M☉
Radius1.02±0.02 R☉
Luminosity1.26±0.02 L☉
Surface gravity (log g)4.44±0.02 cgs
Temperature6060±42 K
Metallicity−0.11±0.01[6]
Age2.2±1.3 Gyr
HD 7449 B
Mass0.23+0.22
−0.05[3] M☉
Mass178.151+16.614
−13.664[4] MJup
Temperature3000 K
Other designations
BD−05 215, HD 7449, HIP 5806, TYC 4683-883-1, 2MASS J01142933-0502504[7]
Database references
SIMBADdata

HD 7449 is a binary star system about 126 light-years way. The primary star, HD 7449 A, is a main-sequence star belonging to the spectral class F9.5. It is younger than the Sun. The primary star is slightly depleted of heavy elements, having 80% of solar abundance.[6]

Companion

The stellar companion HD 7449 B, belonging to spectral class M4.5, was discovered in 2015.[8] A survey in 2017 has failed to find additional stars with masses above 0.35M☉ in the system.[9]

The most recent parameters for HD 7449 B as of 2022 come from a combination of data from radial velocity, astrometry, and imaging, showing that it is about 178 MJ (0.17 M☉), and orbiting with a semi-major axis of about 34.7 AU and an orbital period of about 175 years.[4]

Planetary system

In 2011 one super-Jupiter-mass planet, HD 7449 Ab on a very eccentric orbit around HD 7449 A was discovered utilising the radial velocity method.[6] A second, long-term radial velocity trend is present, and a second planet or brown dwarf has been proposed as the cause of this trend.[6][10] However, in 2015 a low-mass stellar companion (HD 7449 B) was found, which is likely the cause of the long-term trend. The large eccentricity of the inner planet is likely caused by this stellar companion.[3] In 2022, the inclination and true mass of HD 7449 Ab were measured via astrometry.[4]

The HD 7449 A planetary system[4]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(years)		 Eccentricity Inclination Radius
b 8.174+3.055
−2.699 MJ		 2.438+0.062
−0.063		 3.479+0.029
−0.020		 0.752+0.035
−0.032		 171.631+2.609
−3.740°		 —

References

  1. 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.
  2. 1 2 3 4 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.
  3. 1 2 3 Rodigas, Timothy J.; Arriagada, Pamela; Faherty, Jackie; Anglada-Escudé, Guillem; Kaib, Nathan; Butler, R. Paul; Shectman, Stephen; Weinberger, Alycia; Males, Jared R.; Morzinski, Katie M.; Close, Laird M.; Hinz, Philip M.; Crane, Jeffrey D.; Thompson, Ian; Teske, Johanna; Díaz, Matías; Minniti, Dante; Lopez-Morales, Mercedes; Adams, Fred C.; Boss, Alan P. (2016). "MagAO Imaging of Long-period Objects (MILO). I. A Benchmark M Dwarf Companion Exciting a Massive Planet around the Sun-like Star HD 7449". The Astrophysical Journal. 818 (2): 106. arXiv:1512.04540. Bibcode:2016ApJ...818..106R. doi:10.3847/0004-637X/818/2/106. S2CID 51813840.
  4. 1 2 3 4 5 Feng, Fabo; Butler, R. Paul; et al. (August 2022). "3D Selection of 167 Substellar Companions to Nearby Stars". The Astrophysical Journal Supplement Series. 262 (21): 21. arXiv:2208.12720. Bibcode:2022ApJS..262...21F. doi:10.3847/1538-4365/ac7e57. S2CID 251864022.
  5. ↑ Bonfanti, A.; Ortolani, S.; Nascimbeni, V. (2016), "Age consistency between exoplanet hosts and field stars", Astronomy & Astrophysics, 585: A5, arXiv:1511.01744, Bibcode:2016A&A...585A...5B, doi:10.1051/0004-6361/201527297, S2CID 53971692
  6. 1 2 3 4 Dumusque, X.; Lovis, C.; Ségransan, D.; Mayor, M.; Udry, S.; Benz, W.; Bouchy, F.; Lo Curto, G.; Mordasini, C.; Pepe, F.; Queloz, D.; Santos, N. C.; Naef, D. (2011), "The HARPS search for southern extra-solar planets. XXX. Planetary systems around stars with solar-like magnetic cycles and short-term activity variation", Astronomy & Astrophysics, 535: A55, arXiv:1107.1748, Bibcode:2011A&A...535A..55D, doi:10.1051/0004-6361/201117148, S2CID 119192207
  7. ↑ "HD 7449". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 10 October 2020.
  8. ↑ Open Exoplanet Catalogue an open source database of all discovered extrasolar planets HD 7449
  9. ↑ Wittrock, Justin M.; Kane, Stephen R.; Horch, Elliott P.; Howell, Steve B.; Ciardi, David R.; Everett, Mark E. (2017), "Exclusion of Stellar Companions to Exoplanet Host Stars", The Astronomical Journal, 154 (5): 184, arXiv:1709.05315, Bibcode:2017AJ....154..184W, doi:10.3847/1538-3881/aa8d69, S2CID 55789971
  10. ↑ Wittenmyer, Robert A.; Clark, Jake T.; Zhao, Jinglin; Horner, Jonathan; Wang, Songhu; Johns, Daniel (2019), "Truly eccentric. I. Revisiting eight single-eccentric planetary systems", Monthly Notices of the Royal Astronomical Society, 484 (4): 5859–5867, arXiv:1901.08471, Bibcode:2019MNRAS.484.5859W, doi:10.1093/mnras/stz290, S2CID 118915974
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