Astronomy:HD 216446
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| Observation data {{#ifeq:J2000|J2000.0 (ICRS)|Epoch J2000.0 Equinox J2000.0 (ICRS)| Epoch J2000 [[Astronomy:Equinox (celestial coordinates)|Equinox J2000}} | |
|---|---|
| Constellation | Cepheus[1] |
| A | |
| Right ascension | 22h 47m 29.06915s[2] |
| Declination | +83° 09′ 13.7835″[2] |
| Apparent magnitude (V) | 4.92[3] |
| B | |
| Right ascension | 22h 47m 30.42293s[4] |
| Declination | +83° 09′ 16.8515″[4] |
| Apparent magnitude (V) | 9.60[3] |
| Characteristics | |
| A | |
| Evolutionary stage | red giant branch[2] |
| Spectral type | K3III[5] |
| B−V color index | 1.257±0.008[1] |
| Astrometry | |
| A | |
| Radial velocity (Rv) | −32.23±0.13[2] km/s |
| Proper motion (μ) | RA: +24.058±0.174[2] mas/yr Dec.: +47.224±0.114[2] mas/yr |
| Parallax (π) | 10.3313 ± 0.1051[2] mas |
| Distance | 316 ± 3 ly (96.8 ± 1.0 pc) |
| Absolute magnitude (MV) | −0.14[1] |
| B | |
| Proper motion (μ) | RA: +28.006±0.026[4] mas/yr Dec.: +46.796±0.22[4] mas/yr |
| Parallax (π) | 10.5137 ± 0.0185[4] mas |
| Distance | 310.2 ± 0.5 ly (95.1 ± 0.2 pc) |
| Details | |
| A | |
| Mass | 3.8[2] M☉ |
| Radius | 21.9[6] R☉ |
| Luminosity | 167[6] L☉ |
| Surface gravity (log g) | 1.87[6] cgs |
| Temperature | 4,440[6] K |
| Metallicity [Fe/H] | −0.10±0.06[1] dex |
| Rotational velocity (v sin i) | 1.0[7] km/s |
| Age | 6.9[6] Gyr |
| B | |
| Mass | 0.88[8] M☉ |
| Radius | 1.00[8] R☉ |
| Luminosity | 0.64[8] L☉ |
| Surface gravity (log g) | 4.51[9] cgs |
| Temperature | 5,191[8] K |
| Other designations | |
| Database references | |
| SIMBAD | data |
HD 216446 is a binary star[11] system in the northern circumpolar constellation of Cepheus. It is faintly visible to the naked eye with a combined apparent visual magnitude of 4.77.[1] The system is located at a distance of approximately 316 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −32 km/s.[2] It is predicted to come to within 188.7 light-years in around 1.876 million years.[1] The system has an absolute magnitude of −0.14.[1]
The magnitude 4.92[3] primary, designated component A, is an aging giant star with a stellar classification of K3III.[5] The luminosity class of III typically indicates that the star has exhausted the supply of hydrogen at its core, then cooled and expanded off the main sequence. At present it has 22 times the radius of the Sun.[6] The star has a lower abundance of elements other than hydrogen and helium compared to the Sun; what astronomers term the star's metallicity. It is radiating 167 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,440 K.[6]
The secondary companion, component B, is a magnitude 9.60 star located at an angular separation of 3.50″ from the primary, along a position angle of 38°, as of 1992.[3]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A XHIP record for this object at VizieR.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 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.
- ↑ 3.0 3.1 3.2 3.3 Mason, B. D. et al. (2014). "The Washington Visual Double Star Catalog". The Astronomical Journal 122 (6): 3466–3471. doi:10.1086/323920. Bibcode: 2001AJ....122.3466M.
- ↑ 4.0 4.1 4.2 4.3 4.4 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.
- ↑ 5.0 5.1 Abt, H. A. (September 1985). "Visual multiples. VIII - 1000 MK types". Astrophysical Journal Supplement Series 59: 95–112. doi:10.1086/191064. Bibcode: 1985ApJS...59...95A.
- ↑ 6.0 6.1 6.2 6.3 6.4 6.5 6.6 Kordopatis, G.; Schultheis, M.; McMillan, P. J.; Palicio, P. A.; De Laverny, P.; Recio-Blanco, A.; Creevey, O.; Álvarez, M. A. et al. (2023). "Stellar ages, masses, extinctions, and orbital parameters based on spectroscopic parameters of Gaia DR3". Astronomy and Astrophysics 669: A104. doi:10.1051/0004-6361/202244283. Bibcode: 2023A&A...669A.104K.
- ↑ De Medeiros, J. R.; Mayor, M. (1999). "A catalog of rotational and radial velocities for evolved stars". Astronomy and Astrophysics Supplement Series 139 (3): 433. doi:10.1051/aas:1999401. Bibcode: 1999A&AS..139..433D.
- ↑ 8.0 8.1 8.2 8.3 Hardegree-Ullman, Kevin K.; Apai, Dániel; Bergsten, Galen J.; Pascucci, Ilaria; López-Morales, Mercedes (2023). "Bioverse: A Comprehensive Assessment of the Capabilities of Extremely Large Telescopes to Probe Earth-like O2 Levels in Nearby Transiting Habitable-zone Exoplanets". The Astronomical Journal 165 (6): 267. doi:10.3847/1538-3881/acd1ec. Bibcode: 2023AJ....165..267H.
- ↑ Anders, F.; Khalatyan, A.; Queiroz, A. B. A.; Chiappini, C.; Ardèvol, J.; Casamiquela, L.; Figueras, F.; Jiménez-Arranz, Ó. et al. (2022). "Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia EDR3 stars brighter than G = 18.5". Astronomy and Astrophysics 658: A91. doi:10.1051/0004-6361/202142369. Bibcode: 2022A&A...658A..91A.
- ↑ "HD 216446". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+216446.
- ↑ Eggleton, P. P.; Tokovinin, A. A. (September 2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society 389 (2): 869–879. doi:10.1111/j.1365-2966.2008.13596.x. Bibcode: 2008MNRAS.389..869E.
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