Gliese 176 is a small star with an orbiting exoplanet in the constellation of Taurus. With an apparent visual magnitude of 9.95,^[2] it is too faint to be visible to the naked eye. It is located at a distance of 30.9 light years based on parallax measurements,^[1] and is drifting further away with a heliocentric radial velocity of 26.4 km/s.^[3]

This is an M-type main-sequence star, sometimes called a red dwarf, with a stellar classification of M2V.^[3] It has 49% of the Sun's mass and 47% of the radius of the Sun. The star is radiating just 3.5% of the luminosity of the Sun from its photosphere at an effective temperature of 3,632 K. It is estimated to be around nine billion years old,^[5] and is spinning slowly with a rotation period of 40 days. The star is orbited by a Super-Earth.

A planetary companion to Gliese 176 was announced in 2008.^[7] Radial velocity observations with the Hobby-Eberly Telescope (HET) showed a 10.24-day periodicity, which was interpreted as being caused by a planet. With a semi-amplitude of 11.6 m/s, its minimum mass equated to 24.5 Earth masses, or approximately 1.4 Neptune masses.

Observations with the HARPS spectrograph could not confirm the 10.24-day variation.^[3] Instead, two other periodicities were detected at 8.78 and 40.0 days, with amplitudes below the HET observational errors. The 40-day variation coincides with the rotational period of the star and is therefore caused by activity, but the shorter-period variation is not explained by activity and is therefore caused by a planet. Its semi-amplitude of 4.1 m/s corresponds to a minimum mass of 8.4 Earth masses, making the planet a Super-Earth.

In an independent study, observations with Keck-HIRES also failed to confirm the 10.24-day signal.^[8] An 8.77-day periodicity - corresponding to the planet announced by the HARPS team - was detected to intermediate significance, though it was not deemed significant enough to claim a planetary cause with their data alone.

• List of extrasolar planets
• Gliese 674