HD 89744
HD 89744 is a star in the northern circumpolar constellation of Ursa Major, positioned about 0.4° due south of the bright star Tania Australis (μ UMa).[11] This object has a yellow-white hue and is dimly visible to the naked eye with an apparent visual magnitude of 5.73.[2] The distance to this star has been measured using the patallax method, which locates it 126 light years from the Sun. It is drifting closer with a radial velocity of −4.4 km/s.[2] There are two known exoplanets orbiting this star.
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Ursa Major |
| Right ascension | 10h 22m 10.5623s[1] |
| Declination | +41° 13′ 46.3088″[1] |
| Apparent magnitude (V) | 5.73[2] |
| Characteristics | |
| Evolutionary stage | Main sequence |
| Spectral type | F7V[3] or F8IV[4] |
| B−V color index | 0.531±0.003[2] |
| Astrometry | |
| Radial velocity (Rv) | −4.35±0.12[2] km/s |
| Proper motion (μ) | RA: −120.573±0.111[1] mas/yr Dec.: −138.144±0.131[1] mas/yr |
| Parallax (π) | 25.8537 ± 0.0716[1] mas |
| Distance | 126.2 ± 0.3 ly (38.7 ± 0.1 pc) |
| Absolute magnitude (MV) | 2.83[5] |
| Details | |
| A | |
| Mass | 1.37±0.09[6] M☉ |
| Radius | 2.16+0.06 −0.01[1] R☉ |
| Luminosity | 6.38±0.02[7] L☉ |
| Surface gravity (log g) | 4.27±0.05[6] cgs |
| Temperature | 6,381±43[6] K |
| Metallicity [Fe/H] | 0.30±0.03[6] dex |
| Rotation | ~9 days[7] |
| Rotational velocity (v sin i) | 9.3[8] km/s |
| Age | 8.4[7] Gyr |
| B | |
| Mass | 0.076[9] M☉ |
| Other designations | |
| Database references | |
| SIMBAD | The star |
| planet b | |
| Exoplanet Archive | data |
| ARICNS | data |
At various times the star HD 89744 has been assigned a stellar classification of F7V,[3][12] F7IV-V,[13] and F8IV,[4][2] suggesting it is an F-type main-sequence star that is evolving onto the subgiant branch. It is ~8.4[7] billion years old with an inactive chromosphere[13] and is spinning with a projected rotational velocity of 9.3 km/s.[8] The star is 2.16[1] times the size of the Sun with 1.4[6] times the Sun's radius. It is a high metallicity star, showing a greater abundance of heavier elements than in the Sun. The star is radiating 6.4[7] times the luminosity of the Sun from its photosphere at an effective temperature of 6,381 K.[6]
In 2001, a faint co-moving companion was identified at an angular separation of 63.1″ from the primary.[14] This is equivalent to a linear projected separation of 2,456 AU (0.04 ly).[9] The companion, designated component B, is an L-class (~L0.5)[3] brown dwarf[14] with a mass of ~0.076 M☉.[9]
Planetary system
In April 2000, a planet was discovered using radial velocity measurements taken at Fred Lawrence Whipple Observatory and Lick Observatory.[12] The orbital parameters were updated in 2006 and 2007 using additional measurements.[15][16] A second planet with a much longer period was discovered in 2019.[17]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | >8.35±0.18 MJ | 0.917±0.009 | 256.78±0.02 | 0.677±0.003 | — | — |
| c | >5.36±4.57 MJ | 8.3±1.8 | 6,974±2,161 | 0.29±0.12 | — | — |
See also
- List of extrasolar planets
References
- 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.
- 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.
- Scholz, R. -D. (March 2016). "Overlooked wide companions of nearby F stars". Astronomy & Astrophysics. 587: 8. arXiv:1601.01896. Bibcode:2016A&A...587A..51S. doi:10.1051/0004-6361/201527965. A51.
- Gray, R. O.; et al. (July 2006). "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 parsecs: The Northern Sample I". The Astronomical Journal. 132 (1): 161–170. arXiv:astro-ph/0603770. Bibcode:2006AJ....132..161G. doi:10.1086/504637.
- Pizzolato, N.; et al. (September 2000). "Evolution of X-ray activity of 1-3 Msun late-type stars in early post-main-sequence phases". Astronomy and Astrophysics. 361: 614–628. Bibcode:2000A&A...361..614P.
- Sousa, S. G.; et al. (November 2018). "SWEET-Cat updated. New homogenous spectroscopic parameters". Astronomy & Astrophysics. 620: 13. arXiv:1810.08108. Bibcode:2018A&A...620A..58S. doi:10.1051/0004-6361/201833350. S2CID 119374557. A58.
- Metcalfe, Travis S.; Egeland, Ricky (January 2019). "Understanding the Limitations of Gyrochronology for Old Field Stars". The Astrophysical Journal. 871 (1): 6. arXiv:1811.11905. Bibcode:2019ApJ...871...39M. doi:10.3847/1538-4357/aaf575. 39.
- Morris, Brett M.; et al. (September 2019). "Stellar Properties of Active G and K Stars: Exploring the Connection between Starspots and Chromospheric Activity". The Astronomical Journal. 158 (3): 16. arXiv:1907.00423. Bibcode:2019AJ....158..101M. doi:10.3847/1538-3881/ab2e04. 101.
- Mugrauer, M.; et al. (2005). "Four new wide binaries among exoplanet host stars". Astronomy and Astrophysics. 440 (3): 1051–1060. arXiv:astro-ph/0507101. Bibcode:2005A&A...440.1051M. doi:10.1051/0004-6361:20042297.
- "HD 89744". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-10-14.
- Sinnott, Roger W.; Perryman, Michael A. C. (1997). Millennium Star Atlas. 2. Sky Publishing Corporation and the European Space Agency. p. 617. ISBN 0-933346-83-2.
- Korzennik, Sylvain G.; et al. (2000). "A High-Eccentricity Low-Mass Companion to HD 89744". The Astrophysical Journal Letters. 533 (2): L147–L150. arXiv:astro-ph/0003045. Bibcode:2000ApJ...533L.147K. doi:10.1086/312611. PMID 10770711.
- Wright, J. T. (September 2004). "Do We Know of Any Maunder Minimum Stars?". The Astronomical Journal. 128 (3): 1273–1278. arXiv:astro-ph/0406338. Bibcode:2004AJ....128.1273W. doi:10.1086/423221.
- Wilson, J. C.; et al. (October 2001). "Three Wide-Separation L Dwarf Companions from the Two Micron All Sky Survey: Gliese 337C, Gliese 618.1B, and HD 89744B". The Astronomical Journal. 122 (4): 1989–2000. arXiv:astro-ph/0108424. Bibcode:2001AJ....122.1989W. doi:10.1086/323134.
- Butler, R. P.; et al. (2006). "Catalog of Nearby Exoplanets". The Astrophysical Journal. 646 (1): 505–522. arXiv:astro-ph/0607493. Bibcode:2006ApJ...646..505B. doi:10.1086/504701.
- Wittenmyer, Robert A.; et al. (2007). "Dynamical and Observational Constraints on Additional Planets in Highly Eccentric Planetary Systems". The Astronomical Journal. 134 (3): 1276–1284. arXiv:0706.1962. Bibcode:2007AJ....134.1276W. doi:10.1086/520880.
- Wittenmyer, Robert A.; et al. (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.