Astronomy:HD 7449
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| 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[1] mas/yr Dec.: −134.382±0.028[1] mas/yr |
| Parallax (π) | 25.9132 ± 0.0287[1] mas |
| Distance | 125.9 ± 0.1 ly (38.59 ± 0.04 pc) |
| Absolute magnitude (MV) | 4.55[2] |
| Orbit[4] | |
| 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 astronomical unit|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 | |
| 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[6] |
| Age | 2.2±1.3 Gyr |
| HD 7449 B | |
| Mass | 0.23+0.22 −0.05[3] M☉ |
| Mass | 178.151+16.614 −13.664[4] MJup |
| Temperature | 3000 K |
| Other designations | |
| 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 |♃|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]
| 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
- ↑ 1.0 1.1 1.2 1.3 1.4 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.
- ↑ 2.0 2.1 2.2 2.3 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A.
- ↑ 3.0 3.1 3.2 Rodigas, Timothy J.; Arriagada, Pamela; Faherty, Jackie; Anglada-Escudé, Guillem; Kaib, Nathan; Butler, R. Paul; Shectman, Stephen; Weinberger, Alycia et al. (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. doi:10.3847/0004-637X/818/2/106. Bibcode: 2016ApJ...818..106R.
- ↑ 4.0 4.1 4.2 4.3 4.4 Feng, Fabo et al. (August 2022). "3D Selection of 167 Substellar Companions to Nearby Stars". The Astrophysical Journal Supplement Series 262 (21): 21. doi:10.3847/1538-4365/ac7e57. Bibcode: 2022ApJS..262...21F.
- ↑ Bonfanti, A.; Ortolani, S.; Nascimbeni, V. (2016), "Age consistency between exoplanet hosts and field stars", Astronomy & Astrophysics 585: A5, doi:10.1051/0004-6361/201527297, Bibcode: 2016A&A...585A...5B
- ↑ 6.0 6.1 6.2 6.3 Dumusque, X.; Lovis, C.; Ségransan, D.; Mayor, M.; Udry, S.; Benz, W.; Bouchy, F.; Lo Curto, G. et al. (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, doi:10.1051/0004-6361/201117148, Bibcode: 2011A&A...535A..55D
- ↑ "HD 7449". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+7449.
- ↑ 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, doi:10.3847/1538-3881/aa8d69, Bibcode: 2017AJ....154..184W
- ↑ 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, doi:10.1093/mnras/stz290, Bibcode: 2019MNRAS.484.5859W
Coordinates: 
01h 14m 29.3222s, −05° 02′ 50.6148″
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