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HD 7449
Observation data; Epoch J2000 Equinox J2000
Constellation	Cetus
Right ascension	01h 14m 29.32229s
Declination	−05° 02′ 50.6148″
Apparent magnitude (V)	7.50
Characteristics
Spectral type	F9.5V + M4.5
B−V color index	0.575±0.007
Astrometry
Radial velocity (Rv)	−19.60±0.13 km/s
Proper motion (μ)	RA: −164.544±0.039 mas/yr ; Dec.: −134.382±0.028 mas/yr
Parallax (π)	25.9132 ± 0.0287 mas
Distance	125.9 ± 0.1 ly ; (38.59 ± 0.04 pc)
Absolute magnitude (MV)	4.55
Orbit
Primary	HD 7449 A
Companion	HD 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
HD 7449 A
Mass	1.05±0.02 M☉
Radius	1.02±0.02 R☉
Luminosity	1.26±0.02 L☉
Surface gravity (log g)	4.44±0.02 cgs
Temperature	6060±42 K
Metallicity	−0.11±0.01
Age	2.2±1.3 Gyr
HD 7449 B
Mass	0.23+0.22; −0.05 M☉
Mass	178.151+16.614; −13.664 MJup
Temperature	3000 K
Other designations
	BD−05 215, HD 7449, HIP 5806, TYC 4683-883-1, 2MASS J01142933-0502504
Database references
SIMBAD	data

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 M_J (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 [fr] 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 $M$ _J	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

^ ^a ^b ^c ^d ^e 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.
^ ^a ^b ^c ^d 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.
^ ^a ^b ^c 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.
^ ^a ^b ^c ^d ^e 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.
^ 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
^ ^a ^b ^c ^d 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
^ "HD 7449". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 10 October 2020.
^ Open Exoplanet Catalogue an open source database of all discovered extrasolar planets HD 7449
^ 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
^ 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