Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Ara |
Right ascension | 17h 11m 15.72180s [1] |
Declination | −56° 40′ 50.8706″ [1] |
Apparent magnitude (V) | 7.25 [2] |
Characteristics | |
Spectral type | G5IV-V [3] |
B−V color index | 0.699±0.001 [2] |
Variable type | Constant [4] |
Astrometry | |
Radial velocity (Rv) | +28.06±0.15 [1] km/s |
Proper motion (μ) |
RA: 87.585
[1]
mas/
yr Dec.: −55.891 [1] mas/ yr |
Parallax (π) | 15.7321 ± 0.0385 mas [1] |
Distance | 207.3 ± 0.5
ly (63.6 ± 0.2 pc) |
Absolute magnitude (MV) | 3.07 [3] |
Details | |
Mass | 1.718+0.03 −0.022 [5] M☉ |
Radius | 2.1±0.1 [4] R☉ |
Luminosity | 4.4±0.3 [4] L☉ |
Surface gravity (log g) | 3.83±0.03 [4] cgs |
Temperature | 5,740±46 [4] K |
Metallicity [Fe/H] | −0.26±0.01 [6] dex |
Rotational velocity (v sin i) | 1.44±0.50 [7] km/s |
Age | 5.8±0.5 [4] Gyr |
Other designations | |
Database references | |
SIMBAD | data |
HD 154857 is a star with two exoplanetary companions in the southern constellation of Ara. It is too dim to be visible with the naked eye having an apparent visual magnitude of 7.25. [2] The star is located at a distance of 207 light years from the Sun based on parallax measurements, and is drifting further away with a radial velocity of +28 km/s. [1]
This is a G-type star with a stellar classification of G5IV-V. [3] The absolute magnitude of this star is two magnitudes above the main sequence, which suggests that the star is evolving toward the subgiant stage. [3] It is a metal-poor thin disk star [9] approximately six billion years old and is chromopherically quiet although not in a Maunder Minimum state. [4] The star is larger, more massive, and more luminous than the Sun. It is spinning with a projected rotational velocity of 1.4 km/s. [7]
The discovery of one confirmed and one unconfirmed Jovian exoplanet was reported in 2004 [3] and 2007 [10] respectively. The former planet HD 154857 b has mass >1.8 times that of Jupiter. It orbits the star 20% further than Earth- Sun distance, taking 409 days with 47% eccentricity. The additional object ( HD 154857 c) was confirmed as a planetary companion in January 2014. [5]
Companion (in order from star) |
Mass |
Semimajor axis ( AU) |
Orbital period ( days) |
Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
b | ≥ 2.24±0.05 MJ | 1.291±0.008 | 408.6±0.5 | 0.06±0.05 | — | — |
c | ≥ 2.58±0.16 MJ | 5.36±0.09 | 3,452±105 | 0.06±0.05 | — | — |
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Ara |
Right ascension | 17h 11m 15.72180s [1] |
Declination | −56° 40′ 50.8706″ [1] |
Apparent magnitude (V) | 7.25 [2] |
Characteristics | |
Spectral type | G5IV-V [3] |
B−V color index | 0.699±0.001 [2] |
Variable type | Constant [4] |
Astrometry | |
Radial velocity (Rv) | +28.06±0.15 [1] km/s |
Proper motion (μ) |
RA: 87.585
[1]
mas/
yr Dec.: −55.891 [1] mas/ yr |
Parallax (π) | 15.7321 ± 0.0385 mas [1] |
Distance | 207.3 ± 0.5
ly (63.6 ± 0.2 pc) |
Absolute magnitude (MV) | 3.07 [3] |
Details | |
Mass | 1.718+0.03 −0.022 [5] M☉ |
Radius | 2.1±0.1 [4] R☉ |
Luminosity | 4.4±0.3 [4] L☉ |
Surface gravity (log g) | 3.83±0.03 [4] cgs |
Temperature | 5,740±46 [4] K |
Metallicity [Fe/H] | −0.26±0.01 [6] dex |
Rotational velocity (v sin i) | 1.44±0.50 [7] km/s |
Age | 5.8±0.5 [4] Gyr |
Other designations | |
Database references | |
SIMBAD | data |
HD 154857 is a star with two exoplanetary companions in the southern constellation of Ara. It is too dim to be visible with the naked eye having an apparent visual magnitude of 7.25. [2] The star is located at a distance of 207 light years from the Sun based on parallax measurements, and is drifting further away with a radial velocity of +28 km/s. [1]
This is a G-type star with a stellar classification of G5IV-V. [3] The absolute magnitude of this star is two magnitudes above the main sequence, which suggests that the star is evolving toward the subgiant stage. [3] It is a metal-poor thin disk star [9] approximately six billion years old and is chromopherically quiet although not in a Maunder Minimum state. [4] The star is larger, more massive, and more luminous than the Sun. It is spinning with a projected rotational velocity of 1.4 km/s. [7]
The discovery of one confirmed and one unconfirmed Jovian exoplanet was reported in 2004 [3] and 2007 [10] respectively. The former planet HD 154857 b has mass >1.8 times that of Jupiter. It orbits the star 20% further than Earth- Sun distance, taking 409 days with 47% eccentricity. The additional object ( HD 154857 c) was confirmed as a planetary companion in January 2014. [5]
Companion (in order from star) |
Mass |
Semimajor axis ( AU) |
Orbital period ( days) |
Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
b | ≥ 2.24±0.05 MJ | 1.291±0.008 | 408.6±0.5 | 0.06±0.05 | — | — |
c | ≥ 2.58±0.16 MJ | 5.36±0.09 | 3,452±105 | 0.06±0.05 | — | — |