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 |
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.
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]
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 | — | — |