HD 154345
Encyclopedia
HD 154345 is a G-type dwarf star
Star
A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...

 located in northern Hercules
Hercules (constellation)
Hercules is a constellation named after Hercules, the Roman mythological hero adapted from the Greek hero Heracles. Hercules was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and it remains one of the 88 modern constellations today...

. It is not visible to the naked eye since this star is below +6.50 magnitude
Apparent magnitude
The apparent magnitude of a celestial body is a measure of its brightness as seen by an observer on Earth, adjusted to the value it would have in the absence of the atmosphere...

, but using binoculars it is an easy target.

Planetary system

In 2006, a long-period, wide-orbiting planet
Extrasolar planet
An extrasolar planet, or exoplanet, is a planet outside the Solar System. A total of such planets have been identified as of . It is now known that a substantial fraction of stars have planets, including perhaps half of all Sun-like stars...

 was observed by radial velocity
Radial velocity
Radial velocity is the velocity of an object in the direction of the line of sight . In astronomy, radial velocity most commonly refers to the spectroscopic radial velocity...

, and published in May 2007, gaining the designation HD 154345 b
HD 154345 b
HD 154345 b, is a Jupiter-sized extrasolar planet orbiting the star HD 154345.-Discovery:Wright et al. discovered the planet in March 2006 using the radial velocity method to detect the small wobbling movement of the star caused by the gravity of the planet...

.

The complete observation of its nine-year orbit rules out any interior planets of minimum mass (m sini) greater than 0.3 Jupiter. The system's habitable zone
Habitable zone
In astronomy and astrobiology, a habitable zone is an umbrella term for regions that are considered favourable to life. The concept is inferred from the empirical study of conditions favourable for Life on Earth...

 is centred at .754 AU and is narrower than Sol
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...

's. Assuming that the system is oriented edge-on to Earth (inclination ~90, so that the real mass of the planet is about equal to Jupiter's), HD 154345 b does not come close enough to the habitable zone to disrupt the orbits of potential Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...

-like planets in the system.

External links

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