Groombridge 34 Ab
Extrasolar planet List of extrasolar planets
Parent star

<tr> <td colspan="2">Star</td> <td>Groombridge 34</td></tr><tr> <td colspan="2">Constellation</td> <td>Andromeda</td></tr><tr> <td>Right ascension</td> <td style="text-align: center">(α)</td> <td>00h 18m 22.89s</td></tr><tr> <td>Declination</td> <td style="text-align: center">(δ)</td> <td>–44° 01′ 22.6″</td></tr><tr> <td>Apparent magnitude</td> <td style="text-align: center">(mV)</td> <td>8.09</td></tr><tr><td colspan="2">Distance</td><td>11.7 ± 0.1 ly
(3.5 pc)</td></tr><tr><td colspan="2">Spectral type</td> <td>M3.5 + M1.5v</td></tr>

Orbital elements

<tr><td>Semimajor axis</td><td style="text-align: center">(a)</td> <td>0.717 AU</td></tr><tr> <td>Eccentricity</td> <td style="text-align: center">(e)</td> <td>0.12</td></tr><tr><td>Orbital period</td><td style="text-align: center">(P)</td> <td>0.01 y</td></tr>

Physical characteristics

<tr><td>Minimum mass</td><td style="text-align: center">(m sin i)</td><td>1 M</td></tr>

Discovery information

<tr> <td colspan="2">Discovery date</td> <td>August, 2014</td></tr><tr> <td colspan="2">Discoverer(s)</td> <td>>Andrew Howard,</td></tr><tr> <td colspan="2">Discovery method</td> <td>HIRES</td></tr><tr> <td colspan="2">Discovery site</td> <td>Keck Observatory</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>34&p2=b data</td></tr><tr><td colspan=2>SIMBAD</td><td>34+b data</td></tr>

Groombridge 34 Ab is an extrasolar planet approximately 11 light years away in the constellation of Andromeda, and is found in the night sky at Right ascension 00h 18m 22.89s and Declination +44° 01′ 22.6″[1] It was discovered in August of 2014.[2] deduced from analysis of the radial velocities of the parent Star by the Eta-Earth Survey using HIRES at Keck Observatory. Planet "b" has around 5.35 ± 0.75 Earth masses,[3] and is thought to be a super earth with a probable diameter of at least 1.0 times the earths.

Planet b has a close inner orbit around Star A at a semi-major axis of only 0.0717 +/- 0.0034 Aus, making an orbital period that is a little longer than 11.4 days, which appears to be relatively circular (e= 0.12 +0.08/-0.06). It lies closer to the parent star than the probable habital zone and is expected to be unable to harbour life.


  1. F. van Leeuwen (2007) Validation of the new Hipparcos reduction. Astronomy and Astrophysics 474 (2): 653–664.
  2. Groombridge 34 Ab.
  3. Andrew Howard, Geoffrey Marcy, Debra A. Fischer, Howard Isaacson, Philip S. Muirhead, Gregory W. Henry, Tabetha S. Boyajian, Kaspar von Braun, Juliette C. Becker, Jason T. Wright, John Asher Johnson, Astrophysics Earth and Planetary Astrophysics : The NASA-UC-UH Eta-Earth Program: IV. A Low-mass Planet Orbiting an M Dwarf 3.6 PC from Earth.

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