HD 11506
Star in the constellation Cetus
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HD 11506 is a star in the equatorial constellation of Cetus. It has a yellow hue and can be viewed with a small telescope but is too faint to be visible to the naked eye, having an apparent visual magnitude of 7.51.[3] The distance to this object is 167 light-years based on parallax, but it is drifting closer to the Sun with a radial velocity of −7.5 km/s.[2] It has an absolute magnitude of 3.94.[3]
| Observation data Epoch J2000.0 Equinox ICRS | |
|---|---|
| Constellation | Cetus[1] |
| Right ascension | 01h 52m 50.53442s[2] |
| Declination | −19° 30′ 25.1082″[2] |
| Apparent magnitude (V) | 7.51[3] |
| Characteristics | |
| Evolutionary stage | subgiant[2] |
| Spectral type | G0V[4] |
| B−V color index | 0.607±0.015[3] |
| Astrometry | |
| Radial velocity (Rv) | −7.53±0.13[2] km/s |
| Proper motion (μ) | RA: 22.039(22) mas/yr[2] Dec.: −97.904(16) mas/yr[2] |
| Parallax (π) | 19.5342±0.0221 mas[2] |
| Distance | 167.0 ± 0.2 ly (51.19 ± 0.06 pc) |
| Absolute magnitude (MV) | 3.94[3] |
| Details | |
| Mass | 1.22±0.02[5] M☉ |
| Radius | 1.35[6] R☉ |
| Luminosity | 2.17[6] L☉ |
| Surface gravity (log g) | 4.23[6] cgs |
| Temperature | 6,030[6] K |
| Metallicity [Fe/H] | +0.30±0.06[5] dex |
| Rotation | ~15 days[5] |
| Rotational velocity (v sin i) | 5.5±0.5[5] km/s |
| Age | 1.6±0.9[7] Gyr |
| Other designations | |
| BD−20°358, HD 11506, HIP 8770, SAO 148079[8] | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
This object is an ordinary G-type main-sequence star with a stellar classification of G0V,[4] which indicates it is generating energy via hydrogen fusion at its core. It is around 1.6 billion years old[7] and is spinning with a projected rotational velocity of 5 km/s.[9] The star has 122% of the mass of the Sun and 135% of the Sun's radius. The spectrum shows a higher than solar abundance of elements other than hydrogen and helium – what astronomers term the metallicity.[10] The star is radiating twice the Sun's luminosity from its photosphere at an effective temperature of 6,030 K.[6]
Planetary system
The superjovian planet HD 11506 b was discovered orbiting the star by the N2K Consortium in 2007 using the Doppler spectroscopy method.[4] In 2009, a second planet discovery was claimed based on Bayesian analysis of the original data.[11] However, in 2015 additional radial velocity measurements showed that the planetary parameters were significantly different than those determined by Bayesian analysis. An additional linear trend in the radial velocities indicated a stellar or planetary companion on a long term orbit.[10]
In 2022, the presence of a third planet was confirmed, and the mass and inclination of both planet b and the new planet d were measured via astrometry.[12] A 2024 study also confirmed HD 11506 d, but found a significantly wider orbit and greater mass than previously estimated. This object orbits with a 73-year period, and at about 13 times the mass of Jupiter, it is at the borderline of being a brown dwarf.[5]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination (°) |
Radius |
|---|---|---|---|---|---|---|
| c | ≥0.40±0.02 MJ | 0.771±0.004 | 223.92±0.37 | 0.228±0.054 | — | — |
| b | 4.80±0.08 MJ | 2.885±0.016 | 1,617.7±1.9 | 0.379±0.009 | 113+23 −53[12] |
— |
| d | 12.8+0.6 −0.5 MJ |
18.20+0.06 −0.09 |
26,517+256 −292 |
0.29+0.02 −0.03 |
90+6 −5 |
— |