Observation data Epoch J2000.0 Equinox J2000.0 | |
---|---|
Constellation | Ara |
Right ascension | 17h 10m 04.912s [1] |
Declination | −56° 26′ 57.38″ [1] |
Apparent magnitude (V) | 8.22 [2] |
Characteristics | |
Spectral type | G3 IV |
B−V color index | 0.71 |
Astrometry | |
Proper motion (μ) | RA: 31.23 ± 0.75 [1] mas/yr Dec.: -124.69 ± 0.62 [1] mas/yr |
Parallax (π) | 15.44 ± 0.84 [1] mas |
Distance | 210 ± 10 ly (65 ± 4 pc) |
Absolute magnitude (MV) | 4.12 [3] |
Details | |
Mass | 1.06 +0.11 −0.09 [2] M☉ |
Radius | 1.27 +0.1 −0.09 [2] R☉ |
Luminosity | 1.88 [3] L☉ |
Temperature | 5714 (± 30) [2] K |
Metallicity | +0.26 (± 0.04) [2] |
Age | 9.28 +2.18 −2.36 [2] years |
Other designations | |
Database references | |
SIMBAD | data |
Extrasolar Planets Encyclopaedia | data |
HD 154672 is a yellow subgiant (spectral type G3 IV). It is about 65 parsecs away from the Sun that is larger than, but of a similar mass to, the Sun. However, HD 154672 is much older. The star is very metal-rich, which is one of the reasons why it was targeted for a planet search by the N2K Consortium, which discovered the gas giant planet HD 154672 b using Doppler Spectroscopy; the discovery was reported in October 2008. [3] The N2K collaboration chose HD 154672 primarily because it aimed to discover the correlation between a star's metallicity and the mass of orbiting planets. [3]
HD 154672 was targeted by the Magellan Telescopes. It is the host of the first planet discovered from the telescopes by N2K. [3]
HD 154672 was first targeted for a planet search in 2004 by the N2K Consortium, a collaboration of astronomers hoping to take radial velocity measurements of previously untargeted stars using Doppler spectroscopy; however, HD 154672 had been previously targeted by a series of surveys, and was previously included in the Henry Draper catalog and the catalog of the European Space Agency's Hipparcos satellite. [3]
N2K deliberately biased its search towards closely orbiting Jupiter-size planets (Hot Jupiters) in the orbit of metal-rich stars, as the consortium hoped to discover how the mass of a planet relates to its host star's metal content. [3] Initially, HD 154672 was noted as a host to a short-orbit Hot Jupiter, although additional observations revealed that the prospective planetary body had a longer orbit than previously expected, as revealed by the Magellan Telescopes at Chile's Las Campanas Observatory. [3]
Use of the Magellan Clay telescope's Magellan Inamori Kyocera Echelle spectrograph (MIKE) helped collect sixteen radial velocity measurements for HD 154672; a team of American astronomers and one from the Vatican City used these measurements to confirm the existence of planet HD 154672 b and to determine its mass. [3]
The discovery of HD 154672's planet was reported in the Astronomical Journal on October 7, 2008 along with a planet in the orbit of HD 205739. [3]
HD 154672 is a sunlike G-type star that has a mass of 1.06 times that of the Sun and a radius that is 1.27 times that of the Sun. Thus, it is slightly larger than the Sun, although it has a similar mass. The star has an effective temperature of 5714 K, slightly cooler than the Sun; however, it is far richer in iron, with a measured metallicity of [Fe/H] = 0.26. This means that the star has 1.82 times more iron than the Sun does. [2] HD 154672 is far older than the Sun, as its estimated gyrochronological age is estimated at 9.28 billion years. [2] HD 154672's spectrum suggests that the star's chromosphere (its outer layer) is not active. [3]
HD 154672 is located 65.8 parsecs (214.6 light years) away from Earth. It has an apparent magnitude (V) of 8.22, making the star too dim to see from Earth with the naked eye. [2] The star is slightly dimmer than planet Neptune as perceived with the naked eye, which has an apparent magnitude of 7.78 at its brightest. [4] The star's actual brightness is measured with an absolute magnitude of 4.12, [3] similar to that of the Sun.
HD 154672 b is a Hot Jupiter, as it is a closely orbiting planet with a high mass. Specifically, HD 154672 has a mass that is 5.02 times greater than Jupiter's mass. It also orbits at a distance of 0.6 AU, or about 60% of the mean distance between the Earth and Sun. This orbit is completed every 163.91 days. [2]
HD 154672 b has an orbital eccentricity of 0.61, denoting a very elliptical orbit. [2] The planet's discoverers noted that if water existed in the planet's atmosphere, it might change from a liquid state to a gaseous state as the planet swings closer to its host star, increasing its temperature. [3]
Companion (in order from star) | Mass | Semimajor axis (AU) | Orbital period (days) | Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
b | >4.96 MJ | 0.597 | 163.94 ± 0.01 | 0.61 ± 0.03 | — | — |
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HD 69830 d is an exoplanet likely orbiting within the habitable zone of the star HD 69830, the outermost of three such planets discovered in the system. It is located approximately 40.7 light-years (12.49 parsecs, or 3.8505×1014 km) from Earth in the constellation of Puppis. The exoplanet was found by using the radial velocity method, from radial-velocity measurements via observation of Doppler shifts in the spectrum of the planet's parent star.
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HD 8574 b is an extrasolar planet discovered in 2001 by a team of European astronomers using Doppler spectroscopy as part of the ELODIE Planet Search Survey, and was published in a paper with five other planets. HD 8574 b is in the orbit of host star HD 8574. The planet is at most two times the mass of Jupiter, orbiting every 227 days at three quarters of the distance between the Earth and Sun. HD 8574 b has a very elliptical orbit, far more than that of Jupiter.
HD 205739 is a yellow-white hued star in the southern constellation of Piscis Austrinus, positioned near the western constellation boundary with Microscopium. It has the proper name Sāmaya, which was selected in the NameExoWorlds campaign by Sri Lanka, during the 100th anniversary of the IAU. Sāmaya means peace in the Sinhalese language.
HD 154672 b is an extrasolar planet located approximately 210 light-years away in the constellation of Ara, orbiting the metal-rich and aged star HD 154672. This planet has a minimum mass five times that of Jupiter and orbits at about 60% the distance between the Earth to the Sun. Its orbit is very elliptical, which causes temperatures on the planet to vary significantly as it proceeds along its orbit. This planet was discovered in Las Campanas Observatory on September 5, 2008 using the radial velocity method. Along with HD 205739 b, the planets were the first to be discovered by the N2K Consortium using the Magellan Telescopes.
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