HD 154345 b
Extrasolar planet List of extrasolar planets
HD 154345 b and a hypothetical rocky moon.
(Artist's impression)
Parent star

<tr> <td colspan="2">Star</td> <td>HD 154345</td></tr><tr> <td colspan="2">Constellation</td> <td>Hercules</td></tr><tr> <td>Right ascension</td> <td style="text-align: center">(α)</td> <td>17h 02m 36.40s</td></tr><tr> <td>Declination</td> <td style="text-align: center">(δ)</td> <td>+47° 04′ 54.77″</td></tr><tr> <td>Apparent magnitude</td> <td style="text-align: center">(mV)</td> <td>6.74</td></tr><tr><td colspan="2">Distance</td><td>58.91 ± 0.59 ly
(18.06 ± 0.18 pc)</td></tr><tr><td colspan="2">Spectral type</td> <td>G8V</td></tr><tr> <td>Mass</td> <td style="text-align: center">(m)</td> <td>0.88 M</td></tr>

Orbital elements

<tr><td>Semimajor axis</td><td style="text-align: center">(a)</td> <td>4.18 AU
(625 Gm)</td></tr><tr><td> </td> <td style="text-align: center"> </td> <td>89.9 mas</td></tr><tr> <td>Periastron</td> <td style="text-align: center">(q)</td> <td>4.03 AU
(603 Gm)</td></tr><tr> <td>Apastron</td> <td style="text-align: center">(Q)</td> <td>4.33 AU
(647 Gm)</td></tr><tr> <td>Eccentricity</td> <td style="text-align: center">(e)</td> <td>0.036 ± 0.046</td></tr><tr><td>Orbital period</td><td style="text-align: center">(P)</td> <td>3322 ± 93 d
(9.095 y)</td></tr><tr> <td>Orbital speed</td> <td style="text-align: center">(υ)</td> <td>13.7 km/s</td></tr><tr> <td>Inclination</td> <td style="text-align: center">(i)</td> <td>50+40
[1]°</td></tr><tr> <td>Argument of
</td> <td style="text-align: center">(ω)</td> <td>113°</td></tr><tr> <td>Time of periastron</td> <td style="text-align: center">(T0)</td> <td>2,453,230 ± 330 JD</td></tr><tr> <td>Semi-amplitude</td> <td style="text-align: center">(K)</td> <td>14.28 ± 0.75 m/s</td></tr>

Physical characteristics

<tr><td>Mass</td><td style="text-align: center">(m)</td><td>1.2+1.3
[1] MJ</td></tr>

Discovery information

<tr> <td colspan="2">Discovery date</td> <td>March 12, 2006
(confirmed: May 27, 2007)</td></tr><tr> <td colspan="2">Discoverer(s)</td> <td>Wright et al.</td></tr><tr> <td colspan="2">Discovery method</td> <td>radial velocity</td></tr><tr> <td colspan="2">Discovery site</td> <td>United States</td></tr><tr> <td colspan="2">Discovery status</td> <td>published</td></tr> <tr style="background-color: #A0B0FF;"><td align=center colspan=3>Database references</td></tr><tr valign=baseline><td colspan=2>Extrasolar Planets
</td><td>data</td></tr><tr><td colspan=2>SIMBAD</td><td>data</td></tr>

HD 154345 b, is a Jupiter-sized extrasolar planet orbiting the star HD 154345.


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 discovery was confirmed in May 2007.[2]


The planet has a mass at least slightly less than that of Jupiter. It orbits its parent star at the distance of 4.18 AU. Its orbital period is about 9.095 Earth years and its orbit is circular. There are no interior planets of minimum mass (m sini) greater than 0.3 Jupiter.[3] Jupiter-like planets with these orbital and system characteristics are unlikely to be perturbed from the star's inclination.[4] Since the star's inclination is known as around 50°, this would make the planet's most likely mass greater than Jupiter's mass but less than twice that mass.[5]

As such HD 154345 b is presumed to be a gas giant "Jupiter twin".[3] Depending on composition the two planets may be around the same size, or HD 154345 b may be larger. This planet may also harbor a system of moons and rings.

See alsoEdit


  1. 1.0 1.1 Script error
  2. (2007). Four New Exoplanets and Hints of Additional Substellar Companions to Exoplanet Host Stars. The Astrophysical Journal 657 (1): 533–545.
  3. 3.0 3.1 (2008). The Jupiter Twin HD 154345b. The Astrophysical Journal Letters 683 (1): L63–L66.
  4. Roberto Sanchis-Ojeda, Josh N. Winn, Daniel C. Fabrycky (2012). Starspots and spin-orbit alignment for Kepler cool host stars.
  5. hd_154345_b. Extrasolar Planet Encyclopaedia. Retrieved November 12, 2012.

Coordinates: Sky map 17h 02m 36.40s, +47° 04′ 54.77″ Template:Nearest bright star systems

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