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] |
| 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 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
[edit]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
[edit]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]
| 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
[edit]- ^ 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
