# HD 154088

HD 154088
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Ophiuchus
Right ascension 17h 04m 27.84s ± 5.62[1]
Declination −28° 34′ 57.64″ ± 3.16[1]
Apparent magnitude (V) 6.7258 ± 0.005[1]
Characteristics
Spectral type K0V
B−V color index 0.814 ± 0.034[1]
Astrometry
Radial velocity (Rv) 14.2972 ± 0.0003[2] km/s
Proper motion (μ) RA: 83.76 ± 0.64[1] mas/yr
Dec.: -268.69 ± 0.36[1] mas/yr
Parallax (π) 56.06 ± 0.50[1] mas
Distance 58.2 ± 0.5 ly
(17.8 ± 0.2 pc)
Absolute magnitude (MV) 5.47 ± 0.02[3]
Details
Mass 0.97 ± 0.05[4] M
Luminosity 0.68 +0.06
−0.05
(log -0.169 ± 0.033)[6] L
Surface gravity (log g) 4.40 ± 0.11[4] cgs
Temperature 5423 ± 51[4] K
Metallicity [Fe/H] 0.31 ± 0.03[4] dex
Rotation 42.6 ± 4.4[7]
Rotational velocity (v sin i) 1.9 ± 0.5[6] km/s
Age 3 - 8[4] Gyr
Other designations
HIP 83541, Gliese 652
Database references
Extrasolar Planets
Encyclopaedia
data

HD 154088 is a seventh magnitude metal-rich K-type main sequence star that lies approximately 58 light-years away in the constellation of Ophiuchus. The star is orbited by a hot Super-Earth.

## Properties

The position of HD 154088 on the Hertzsprung-Russell diagram.

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 K0V, indicating that it is a 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. 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.[4] It also has a magnetic cycle similar to the Sun,[7] though its length is not well constrained.

## Planetary system

A planet orbiting HD 154088 discovered with the HARPS spectrograph was announced in September 2011. With a minimum mass of 6 Earth masses, the companion falls into the regime of Super-Earths.

The HD 154088 planetary system[2]
Companion
(in order from star)
Mass Semimajor axis
(AU)
Orbital period
(days)
b ≥6.15 ± 0.86 M 0.1316 ± 0.0021 18.596 ± 0.021 0.38 ± 0.15

HD 154088 is also being observed under the Keck Eta-Earth radial velocity survey.[8] HD 154088 b is a close match for planet candidate 1 (orbital period = 18.1 days, minimum mass = 6.5 M), so they may be the same detection.

## References

1. 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.
2. ^ a b c Mayor, M.; et al. (2011). "The HARPS search for southern extra-solar planets XXXIV. Occurrence, mass distribution and orbital properties of super-Earths and Neptune-mass planets". arXiv:1109.2497. Bibcode:2011arXiv1109.2497M.
3. ^ a b The relevant calculation for absolute magnitude is ${\displaystyle M=m-5((\log _{10}{D_{L}})-1)\!\,}$, where ${\displaystyle m\!\,}$ is the apparent magnitude and ${\displaystyle D_{L}\!\,}$ is the distance in parsecs.
4. Fossati, L.; et al. (2013). "Detection of a magnetic field in three old and inactive solar-like planet-hosting stars". arXiv:1302.0879. Bibcode:2013A&A...551A..85F. doi:10.1051/0004-6361/201220997.
5. ^ a b Takeda, Genya; et al. (2007). "Structure and Evolution of Nearby Stars with Planets. II. Physical Properties of ~1000 Cool Stars from the SPOCS Catalog". arXiv:astro-ph/0607235. Bibcode:2007ApJS..168..297T. doi:10.1086/509763.
6. ^ a b c Valenti, J. A.; Fischer, D. A. (2005). "Spectroscopic Properties of Cool Stars (SPOCS). I. 1040 F, G, and K Dwarfs from Keck, Lick, and AAT Planet Search Programs". Bibcode:2005ApJS..159..141V. doi:10.1086/430500.
7. ^ a b c Lovis, C.; et al. (2011). "The HARPS search for southern extra-solar planets. XXXI. Magnetic activity cycles in solar-type stars: statistics and impact on precise radial velocities". arXiv:1107.5325. Bibcode:2011arXiv1107.5325L.
8. ^ a b Howard, Andrew A.; et al. (2010). "The Occurrence and Mass Distribution of Close-in Super-Earths, Neptunes, and Jupiters". arXiv:1011.0143. Bibcode:2010Sci...330..653H. doi:10.1126/science.1194854.