HD 220074
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Cassiopeia |
| Right ascension | 23h 20m 14.380s[1] |
| Declination | +61° 58′ 12.46″[1] |
| Apparent magnitude (V) | +6.39 |
| Characteristics | |
| Spectral type | M2III[2][3] |
| Astrometry | |
| Radial velocity (Rv) | –36.89 ± 0.21[2] km/s |
| Proper motion (μ) | RA: 7.68 ± 0.44[1] mas/yr Dec.: –5.43 ± 0.41[1] mas/yr |
| Parallax (π) | 3.08 ± 0.43[1] mas |
| Distance | approx. 1,100 ly (approx. 320 pc) |
| Absolute magnitude (MV) | – 1.52[2] |
| Details | |
| Mass | 1.2 ± 0.3[3] M☉ |
| Radius | 49.7 ± 9.5[3] R☉ |
| Luminosity | ? L☉ |
| Surface gravity (log g) | 1.3 ± 0.5[2] cgs |
| Temperature | 3935 ± 110[2] K |
| Metallicity | –0.25 ± 0.25[3] |
| Rotation | 3.0[2] |
| Age | 4.5 ± 2.8 × 109[3] years |
| Other designations | |
HD 220074, HIP 115218, HR 8881 | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
| Extrasolar Planets Encyclopaedia | data |
HD 220074 is a M2III red giant star located in Cassiopeia.
It had been considered K1V but is now known as M2III due to radius and surface gravity.[2]
Planetary system
From September 2008 to June 2012, the team B.-C. Lee, I. Han, and M.-G. Park observed HD 220074 with "the high-resolution spectroscopy of the fiber-fed Bohyunsan Observatory Echelle Spectrograph (BOES) at Bohyunsan Optical Astronomy Observatory (BOAO)".
In 2012, a long-period, wide-orbiting eccentric planet was deduced by radial velocity. This was published in November, gaining the designation HD 220074 b.[3] Along with HD 208527 b this is one of the first two planets proposed around a red giant.
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | >11.1 ± 1.8 MJ | 1.6 ± 0.1 | 672.1 ± 3.7 | 0.14 ± 0.05 | — | — |
References
- 1 2 3 4 5 van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752
. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357.Vizier catalog entry - 1 2 3 4 5 6 7 B.-C. Lee, I. Han, M.-G. Park (2012). "Planetary companions orbiting M giants HD208527 and HD 220074". Astronomy & Astrophysics. arXiv:1211.2051. Bibcode:2013A&A...549A...2L. doi:10.1051/0004-6361/201220301.
- 1 2 3 4 5 6 7 "hd_220074_b".
External links
- HR 8881, an orange dwarf star in Cassiopeia (but note, it is not an orange dwarf)
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