| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Ursa Major[1] |
| Right ascension | 11h 44m 40.9643s[2] |
| Declination | +30° 57′ 33.451″[2] |
| Apparent magnitude (V) | 8.96[3] |
| Characteristics | |
| Spectral type | K5 V[3] |
| U−B color index | +1.06[4] |
| B−V color index | +1.111±0.016[1] |
| Astrometry | |
| Radial velocity (Rv) | +29.76±0.35[2] km/s |
| Proper motion (μ) | RA: −27.069±0.081[2] mas/yr Dec.: −381.708±0.079[2] mas/yr |
| Parallax (π) | 38.6381±0.0499 mas[2] |
| Distance | 84.4 ± 0.1 ly (25.88 ± 0.03 pc) |
| Absolute magnitude (MV) | 6.89[3] |
| Details[3] | |
| Mass | 0.73±0.05 M☉ |
| Radius | 0.68±0.03 R☉ |
| Luminosity | 0.19±0.01 L☉ |
| Surface gravity (log g) | 4.71±0.1 cgs |
| Temperature | 4,640±100 K |
| Metallicity [Fe/H] | +0.09±0.05 dex |
| Rotation | 45 d |
| Rotational velocity (v sin i) | 0.5±0.5 km/s |
| Age | 7.87±5 Gyr |
| Other designations | |
| BD+31°2290, Gaia DR2 4021079911593673600, GJ 439, HIP 57274, SAO 62684, LTT 13227, 2MASS J11444095+3057339[5] | |
| Database references | |
| SIMBAD | data |
| ARICNS | data |
HIP 57274 is a star in the northern circumpolar constellation of Ursa Major with a system of three planets.[3] It is invisible to the naked eye, having an apparent visual magnitude of 8.96.[3] The distance to this system is 84.4 light years based on stellar parallax, and it is drifting further away with a radial velocity of +30 km/s.[2] The star has a relatively high rate of proper motion, traversing the celestial sphere at the rate of 0.382 arcsecond/year.[6]
This is an ordinary K-type main-sequence star with a stellar classification of K5V.[3] It appears to be older than the Sun with an age of roughly eight billion years and is spinning slowly with a projected rotational velocity of under 1 km/s. The star has 73% of the mass of the Sun and 68% of the Sun's radius. The abundance of elements heavier than helium is about the same or slightly higher than in the Sun. The star is radiating just 19% of the luminosity of the Sun from its photosphere at an effective temperature of 4,640 K.
Planetary system
[edit]The three exoplanets orbiting HIP 57274 were discovered by the radial velocity method in 2011, all of them having mass significantly greater than the Earth.[3] A 2014 search for planetary transits was unsuccessful.[7] The planetary orbits are possibly highly variable, being strongly affected by mean motion resonances.[8] The most stable region for a hypothetical super-earth within the star's habitable zone would be an orbit inside 0.37–0.56 AU from the host star.[8]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≥11.6±1.3 M🜨 | 0.0713±0.00163 | 8.1352±0.004 | 0.187±0.10 | — | — |
| c | ≥0.41±0.01 MJ | 0.1778±0.0041 | 32.03±0.02 | 0.05±0.02 | — | — |
| d | ≥0.53±0.03 MJ | 1.007±0.027 | 431.7±8.5 | 0.27±0.05 | — | — |
References
[edit]- ^ a b 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. XHIP record for this object at VizieR.
- ^ a b c d e f g 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.
- ^ a b c d e f g h i Fischer, Debra A.; et al. (2012). "M2K. II. A Triple-planet System Orbiting HIP 57274". The Astrophysical Journal. 745 (1). 21. arXiv:1109.2926. Bibcode:2012ApJ...745...21F. doi:10.1088/0004-637X/745/1/21.
- ^ Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. Bibcode:1986EgUBV........0M.
- ^ "BD+31 2290". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 28 August 2017.
- ^ Lépine, Sébastien; Shara, Michael M. (March 2005). "A Catalog of Northern Stars with Annual Proper Motions Larger than 0.15" (LSPM-NORTH Catalog)". The Astronomical Journal. 129 (3): 1483–1522. arXiv:astro-ph/0412070. Bibcode:2005AJ....129.1483L. doi:10.1086/427854. S2CID 2603568.
- ^ Kammer, J. A.; et al. (February 2014). "A Spitzer Search for Transits of Radial Velocity Detected Super-Earths". The Astrophysical Journal. 781 (2): 6. arXiv:1310.7952. Bibcode:2014ApJ...781..103K. doi:10.1088/0004-637X/781/2/103. S2CID 37557541. 103.
- ^ a b c Elser, S.; et al. (2013). "Super Earths and Dynamical Stability of Planetary Systems: First Parallel GPU Simulations Using GENGA". Monthly Notices of the Royal Astronomical Society. 433 (3): 2194–2205. arXiv:1305.4070. Bibcode:2013MNRAS.433.2194E. doi:10.1093/mnras/stt883.
