| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Aquarius |
| Right ascension | 23 25 52.99170 |
| Declination | –20° 36′ 57.6998″ |
| Apparent magnitude (V) | +7.74 |
| Characteristics | |
| Spectral type | G3V |
| B−V color index | +0.603±0.002 |
| Astrometry | |
| Radial velocity (Rv) | +12.30±0.14 km/s |
| Proper motion (μ) | RA: –15.328 mas/yr Dec.: –177.593 mas/yr |
| Parallax (π) | 21.3074 ± 0.0236 mas |
| Distance | 153.1 ± 0.2 ly (46.93 ± 0.05 pc) |
| Absolute magnitude (MV) | 4.50 |
| Details | |
| Mass | 1.016±0.048 M☉ |
| Radius | 1.068±0.047 R☉ |
| Luminosity | 1.491±0.005 L☉ |
| Surface gravity (log g) | 4.360±0.045 cgs |
| Temperature | 5,921±26 K |
| Metallicity | −0.07±0.10 dex |
| Rotation | ~29 d |
| Rotational velocity (v sin i) | 5.5 km/s |
| Age | 4.586±2.487 Gyr |
| Other designations | |
| BD–21°6419, GC 32591, HD 220689, HIP 115662, SAO 191898, G 273-43 | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
HD 220689 is a single star in the equatorial constellation of Aquarius. It is a challenge to view with the naked eye, having an apparent visual magnitude of +7.74, but is readily viewed with a pair of binoculars. The star is located at a distance of 153 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +12 km/s. A survey in 2015 has ruled out the existence of any additional stellar companions at projected distances from 26 to 305 astronomical units.
The stellar classification of HD 220689 is G3V, matching a yellow hued G-type main-sequence star that is generating energy through core hydrogen fusion. It is roughly 4.6 billion years old and is spinning with a projected rotational velocity of 5.5 km/s, giving it a rotation period of around 29 days. The star has a similar size, mass, and elemental abundances as the Sun. It is radiating 1.5 times the luminosity of the Sun from its photosphere at an effective temperature of 5,921 K.
Planetary system
From 1998 to 2012, the star was under observation from the CORALIE echelle spectrograph at La Silla Observatory. In 2012, a long-period, wide-orbiting exoplanet was deduced from radial velocity variations. This was published in November. The maximum orbital period allowing for dynamic stability of a hypothetical inner planet is 3.9 years. In 2023, the inclination and true mass of HD 220689 b were determined via astrometry.
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (years) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | 1.2+0.22 −0.11 MJ |
3.433+0.065 −0.064 |
6.23+0.15 −0.14 |
0.053+0.06 −0.037 |
71+13 −18 or 109+18 −13° |
— |
References
- ^ 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.
- ^ 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.
- ^ Houk, Nancy; Smith-Moore, M. (1978). Michigan catalogue of two-dimensional spectral types for the HD stars. Vol. 4. Ann Arbor: Dept. of Astronomy, University of Michigan. Bibcode:1988mcts.book.....H.
- ^ Barbato, D.; et al. (August 2018). "Exploring the realm of scaled solar system analogues with HARPS". Astronomy & Astrophysics. 615: 21. arXiv:1804.08329. Bibcode:2018A&A...615A.175B. doi:10.1051/0004-6361/201832791. S2CID 119099721. A175.
- ^ 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.
- ^ Luck, R. Earle (March 2018). "Abundances in the Local Region. III. Southern F, G, and K Dwarfs". The Astronomical Journal. 155 (3): 31. Bibcode:2018AJ....155..111L. doi:10.3847/1538-3881/aaa9b5. S2CID 125765376. 111.
- "HD 220689". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-01-02.
- ^ Mugrauer, M.; Ginski, C. (12 May 2015). "High-contrast imaging search for stellar and substellar companions of exoplanet host stars". Monthly Notices of the Royal Astronomical Society. 450 (3): 3127–3136. Bibcode:2015MNRAS.450.3127M. doi:10.1093/mnras/stv771. hdl:1887/49340. Retrieved 19 June 2020.
- "The astronomical magnitude scale". International Comet Quarterly. Retrieved 2020-12-31.
- Marmier, M.; et al. (2013). "The CORALIE survey for southern extrasolar planets XVII. New and updated long period and massive planets". Astronomy and Astrophysics. 551. A90. arXiv:1211.6444. Bibcode:2013A&A...551A..90M. doi:10.1051/0004-6361/201219639. S2CID 59467665.
- ^ Xiao, Guang-Yao; Liu, Yu-Juan; et al. (March 2023). "The Masses of a Sample of Radial-Velocity Exoplanets with Astrometric Measurements". Research in Astronomy and Astrophysics. 23 (5). arXiv:2303.12409. doi:10.1088/1674-4527/accb7e.
External links
- "HD 220689 b". Extrasolar Planets Encyclopaedia. Retrieved 2021-01-02.
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