HD 69830 b
Extrasolar planet List of extrasolar planets
HD 69830 b looking at its star.
(Artist's impression)
Parent star

<tr> <td colspan="2">Star</td> <td>HD 69830</td></tr><tr> <td colspan="2">Constellation</td> <td>Puppis</td></tr><tr> <td>Right ascension</td> <td style="text-align: center">(α)</td> <td>08h 18m 23.947s[1]</td></tr><tr> <td>Declination</td> <td style="text-align: center">(δ)</td> <td>−12° 37′ 55.81″[1]</td></tr><tr> <td>Apparent magnitude</td> <td style="text-align: center">(mV)</td> <td>5.95</td></tr><tr><td colspan="2">Distance</td><td>40.7 ± 0.2[1] ly
(12.49 ± 0.05[1] pc)</td></tr><tr><td colspan="2">Spectral type</td> <td>K0V</td></tr><tr> <td>Mass</td> <td style="text-align: center">(m)</td> <td>0.86 ± 0.03 M</td></tr><tr> <td>Radius</td> <td style="text-align: center">(r)</td> <td>0.89 R</td></tr><tr> <td>Temperature</td> <td style="text-align: center">(T)</td> <td>5385 ± 20 K</td></tr><tr> <td>Metallicity</td> <td style="text-align: center">[Fe/H]</td> <td>−0.05 ± 0.02</td></tr><tr> <td>Age</td> <td style="text-align: center"></td> <td>5.1–6.1 Gyr</td></tr>

Orbital elements

<tr><td>Semimajor axis</td><td style="text-align: center">(a)</td> <td>0.0785 AU</td></tr><tr> <td>Eccentricity</td> <td style="text-align: center">(e)</td> <td>0.1 ± 0.04</td></tr><tr><td>Orbital period</td><td style="text-align: center">(P)</td> <td>8.667 ± 0.003 d</td></tr><tr> <td>Argument of
</td> <td style="text-align: center">(ω)</td> <td>340 ± 26°</td></tr><tr> <td>Time of periastron</td> <td style="text-align: center">(T0)</td> <td>2,453,496.8 ± 0.06 JD</td></tr><tr> <td>Semi-amplitude</td> <td style="text-align: center">(K)</td> <td>3.51 ± 0.15 m/s</td></tr>

Physical characteristics

<tr><td>Minimum mass</td><td style="text-align: center">(m sin i)</td><td>0.033 MJ</td></tr><tr> <td>Temperature</td> <td style="text-align: center">(T)</td> <td>~804 K</td></tr>

Discovery information

<tr> <td colspan="2">Discovery date</td> <td>May 18, 2006</td></tr><tr> <td colspan="2">Discoverer(s)</td> <td>Lovis et al.[2]</td></tr><tr> <td colspan="2">Discovery method</td> <td>Radial velocity</td></tr><tr> <td colspan="2">Discovery status</td> <td>Published[2]</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 69830 b is a Neptune-mass or super-Earth-mass exoplanet orbiting the star HD 69830. It is 10 times more massive than Earth, making it the least massive known exoplanet in the system. It also orbits very close to its parent star and takes 82/3 days to complete an orbit.

This is likely to be a rocky planet, not a gas giant.[2] If it had formed as a gas giant, it would have stayed that way.[3]

If HD 69830 b is a terrestrial planet, models predict that tidal heating would produce a heat flux at the surface of about 55 W/m2. This is 20 times that of Io.[4]


  1. 1.0 1.1 1.2 1.3 (2007). Validation of the new Hipparcos reduction. Astronomy and Astrophysics 474 (2): 653–664.Vizier catalog entry
  2. 2.0 2.1 2.2 (2006). An extrasolar planetary system with three Neptune-mass planets. Nature 441 (7091): 305–309.
  3. H. Lammer et al. (2007). The impact of nonthermal loss processes on planet masses from Neptunes to Jupiters. Geophysical Research Abstracts 9 (07850).
  4. Jackson, Brian (2008). Tidal Heating of Extra-Solar Planets. ApJ 681 (2): 1631.

Coordinates: Sky map 08h 18m 23.9s, −12° 37′ 55.8″