HD 154088
Star in the constellation Ophiuchus
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HD 154088 is a seventh magnitude metal-rich K-type subgiant that lies 59.6 light-years away in the constellation of Ophiuchus. The star is orbited by a hot Super-Earth.
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Ophiuchus[1] |
| Right ascension | 17h 04m 27.843s[2] |
| Declination | −28° 34′ 57.64″[2] |
| Apparent magnitude (V) | 6.584±0.010[3] |
| Characteristics | |
| Evolutionary stage | subgiant[2] |
| Spectral type | K0IV-V[4] |
| B−V color index | 0.814±0.034[1] |
| Astrometry | |
| Radial velocity (Rv) | 14.2972±0.0003[5] km/s |
| Proper motion (μ) | RA: +83.309[2] mas/yr Dec.: −268.614[2] mas/yr |
| Parallax (π) | 54.726±0.0236 mas[2] |
| Distance | 59.60 ± 0.03 ly (18.273 ± 0.008 pc) |
| Absolute magnitude (MV) | 5.33[1] |
| Details | |
| Mass | 0.91±0.02[6] M☉ |
| Radius | 0.95±0.03[7] R☉ |
| Luminosity | 0.68+0.06 −0.05[8] L☉ |
| Surface gravity (log g) | 4.37±0.07[6] cgs |
| Temperature | 5,374±43[6] K |
| Metallicity [Fe/H] | +0.28±0.03[6] dex |
| Rotation | 42.6±4.4[9] days |
| Rotational velocity (v sin i) | 1.9±0.5[8] km/s |
| Age | 8±2[6] Gyr |
| Other designations | |
| CD−28°12769, GJ 652, HIP 83541, SAO 184990 | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
Properties
HD 154088 is a modestly bright star that lies at the bottom of Ophiuchus, near to the border with Scorpius and near to the plane of the Milky Way. The star was recognised as a high proper motion star during the last century, and early Earth-based parallax measurements such as that of the Gliese Catalogue of Nearby Stars indicated a distance of about 50 light-years.
The star has a spectral type of K0IV-V, indicating that it has characteristics intermediate to a subgiant and main sequence star that is about 350 degrees cooler than the Sun. On the Hertzsprung-Russell diagram (left), the star lies slightly above the main sequence. This is because the star is very metal-rich; with an Fe/H of 0.3 dex the star has about twice the solar abundance of iron, which makes HD 154088 fall into the somewhat vague group of super metal-rich (SMR) stars.[citation needed] The giant planet occurrence rate of Fe/H = 0.3 stars is on the order of 30%, but HD 154088 is not currently known to host any giant planets.
HD 154088 has a pronounced magnetic field.[10] It also has a magnetic cycle similar to the Sun,[9] though its length is not well constrained.
A survey in 2015 ruled out the existence of any additional stellar companions at projected distances from 8 to 119 astronomical units.[11]
Planetary system
A planet orbiting HD 154088 discovered with the HARPS spectrograph was announced in a September 2011 preprint. With a minimum mass of 6 M🜨, the companion falls into the regime of Super-Earths.[5] HD 154088 has also been observed under the Keck Eta-Earth radial velocity survey. A 2010 paper about this survey listed a "Candidate 1" that has similar properties to HD 154088 b (orbital period = 18.1 days, minimum mass = 6.5 M🜨), and so may be the same detection.[12] The planet's existence was finally confirmed and formally published in 2021.[6]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≥6.6±0.8 M🜨 | 0.134±0.002 | 18.56±0.01 | <0.344 | — | — |