Lacaille 9352

VLTI, ESO




Larger and jumbo images.




Lacaille 9352 (Gl or GJ 887) is larger
than Alpha Centauri C (Proxima)
and Kapteyn's Star but significantly
smaller than Sol (more from ESO).

Due to Lacaille 9352's proximity to Sol, the star has been an object of high interest among astronomers. It has been selected as a "Tier 1" target star for NASA's optical Space Interferometry Mission (SIM) to detect a planet as small as three Earth-masses within two AUs of its host star (and so some summary system information and may still be available from the SIM Teams). The SIM project manager announced on November 8, 2010, however, that the mission was indefinitely postponed due to withdrawal of NASA funding.

Medialab, © ESA 2002



Larger illustration of
the Darwin Mission.



Astronomers have identified
Lacaille 9352 as a prime target
for NASA's optical SIM and the
ESA's infrared Darwin missions,
now both indefintely postponed.

The Star

This spectral and luminosity type of this cool and dim, main sequence red dwarf may be around M1.5 Ve (RECONS), but it has been classed as orange as M0.5 (Demory et al, 2009, Table 4; and Hawley et al, 1996). Lacaille 9352 may have 50 to 58 of Sol's mass (Demory et al, 2009, Table 4; RECONS; and NASA Star and Exoplanet Database, interpolation table of Henry and McCarthy, 1993), less than half (43 to 46 percent) of its diameter (Demory et al, 2009, Table 4; and NASA Star and Exoplanet Database, derived from the power law formula of Kenneth R. Lang, 1980), 1.1 percent of its visual luminosity and 3.5 percent of its bolometric luminosity (NASA Star and Exoplanet Database, derived from the exponential formula of Kenneth R. Lang, 1980), and only about one tenth to 60 percent of Sol's abundance of elements heavier than hydrogen ("metallicity") (Demory et al, 2009, Table 4). It has been designated with the New Suspected Variable number NSV 14420. Some alternative names and useful catalogue numbers for this star are: Gl 887, Hip 114046, HD 217987, CD-36 15693, CP(D)-36 9694, SAO 214301, LHS 70, LPM 849, LTT 9348, LFT 1758, and Cordoba 31353.

Habitable Zone

Accounting for infrared light, the distance from Lacaile 9352 where an Earth-type planet would be comfortable warm enough to have liquid water is about 0.22 AU (SIM summary data). According to alternative calculations performed for the NASA Star and Exoplanet Database, their estimate of the HZ would be centered around 0.270 AU, with inner edge of Lacaille 9352's habitable zone slightly farther out at around 0.183 AU from the star, while the outer edge lies even farther out at around 0.358 AU. At such close orbital distances, the orbital period would be around 55 days, and the rotation of the planet may become tidally locked with the star so that one side would have perpetual daylight while the other would be in darkness. Moreover, the light emitted by red dwarfs may be too red in color for Earth-type plant life to perform photosynthesis efficiently.

Hunt for Substellar Companions

A recent search for faint companions using the Hubble Space Telescope found no supporting evidence for a large Jupiter or brown dwarf sized object (Schroeder et al, 2000).

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