- Surface temperature
- 3,820 K
- Radius
- 0.24 × the Sun
- Luminosity
- 0.011 × the Sun
- Spectral type
- M2/M3V
Star · Deep guide
Lacaille 9352
A fast-moving southern neighbor with two confirmed super-Earths.
What is it?
Lacaille 9352, 10.7 light-years away in Piscis Austrinus, races across southern skies fast enough to cross a full-Moon width in about 240 years. In 2020 astronomers confirmed two super-Earth planets orbiting it — among the closest known multi-planet systems — with a possible third farther out.
The deep dive
Researched for the Atlas from Wikipedia — Gliese 887 (2,430 characters read) · updated Sep 20, 2026
01 The star that first showed its true size
Lacaille 9352 holds a quiet but genuine place in the history of stellar astronomy: it was the first red dwarf star to have its angular diameter successfully measured. That measurement allowed astronomers to pin down a physical diameter of about 47% of the Sun's radius — meaning you could line up roughly two of these stars side by side and they would still not quite span the width of our own star. The result gave observers a concrete sense of just how physically small red dwarfs really are, turning what had been an abstract spectral category into something with real, measured dimensions. Before that milestone, the sizes of red dwarfs were largely inferred from theoretical models rather than direct observation, so Lacaille 9352 served as an important empirical anchor for understanding the smallest class of hydrogen-burning stars.
02 Benjamin Gould and a star in a hurry
In 1881, the American astronomer Benjamin Gould noticed something unusual in his positional data for this star: it was moving across the sky faster than almost anything else known at the time. The proper motion he recorded — later refined to 6.9 arcseconds per year — ranks Lacaille 9352 as having the fourth highest known proper motion of any star. To put that in perspective, there are 3,600 arcseconds in a single degree of arc, so even at this relatively brisk pace the star takes more than five centuries to drift the width of a full Moon. Gould's detection was a testament to careful, repeated positional measurements rather than anything visible to the casual observer. The high proper motion is largely a consequence of the star's closeness to Earth — at roughly 10.72 light-years away, even modest true velocities translate into noticeable angular shifts when watched over years and decades.
03 How Lacaille 9352 moves through the galaxy Deeper
Beyond its famous angular drift across the sky, Lacaille 9352 has well-measured space velocity components: U equals −93.9 km/s, V equals −14.1 km/s, and W equals −51.4 km/s, describing its full three-dimensional motion relative to the Sun through the Milky Way. The radial velocity — the component coming directly toward or away from us — is +9.7 km/s, meaning the star is currently receding slightly. Working backward with these numbers, astronomers have calculated that approximately 2,700 years ago Lacaille 9352 reached its closest approach to the Sun, a minimum distance of roughly 10.63 light-years (3.26 parsecs). That is actually only marginally closer than its present distance of 10.72 light-years (3.29 parsecs), which tells us we are living near — but just past — the moment of closest passage. The star's trajectory places it among the so-called older, faster-moving disk stars of the galaxy.
04 A dim star in a little-watched constellation
Lacaille 9352 sits in the southern constellation of Piscis Austrinus, the Southern Fish — a relatively obscure patch of sky best known for hosting the bright star Fomalhaut. Despite being the closest star in that entire constellation, Lacaille 9352 shines at an apparent visual magnitude of only 7.34, placing it just below the traditional naked-eye limit of about 6 to 6.5. Under truly exceptional conditions some observers report glimpsing stars this faint, but in practice a pair of binoculars is the minimum tool needed to locate it. The nearest stellar neighbor to Lacaille 9352 is not in our own Solar System but rather the EZ Aquarii triple star system, sitting about 4.1 light-years away in the adjacent constellation. That gap — larger than the Earth-to-Proxima Centauri distance — underscores how genuinely isolated individual star systems are even in the relatively star-rich solar neighborhood.
05 The star's temperature, mass, and classification
The spectrum of Lacaille 9352 pins its stellar classification at M0.5V, placing it at the warmer end of the red dwarf sequence, right on the boundary between late K-type and M-type stars. Its outer envelope radiates at an effective temperature of about 3,670 Kelvin — compare that to the Sun's roughly 5,778 Kelvin surface, and you get a sense of how much cooler and redder this star appears. In mass it comes to around half that of the Sun. These three figures together — spectral type, temperature, and mass — paint a coherent picture of a stable, long-lived main sequence star. Red dwarfs of this mass burn hydrogen so frugally that they can remain on the main sequence for tens to hundreds of billions of years, far outlasting the Sun's estimated 10-billion-year lifespan. Lacaille 9352 is in no particular hurry to evolve.
06 Two confirmed super-Earths and a growing tally
In June 2020, astronomers announced two super-Earth planets orbiting Lacaille 9352, detected using the radial velocity method — watching for the tiny wobbles the planets' gravity induces in the star's light. The observations came from two of the world's premier planet-hunting instruments: HARPS, operated in Chile, and HIRES, located in Hawaii. At the same announcement, a third candidate planet with an orbital period of 50.7 days was flagged, though it had not yet been confirmed. A 2026 follow-up study then confirmed that 50-day planet and added a fourth world — one with a mass closer to Earth's — orbiting nearer to the star. Researchers also noted a fifth candidate signal in the data. The system has therefore gone from zero known planets to a confirmed pair plus strong evidence for at least two or three additional worlds in a span of roughly six years, a reminder of how quickly our picture of nearby planetary systems can change.
07 The habitable-zone planet and what we don't know Deeper
The confirmed planet GJ 887 d, orbiting with a period of 50.7 days, sits within the star's habitable zone — the range of distances where liquid water could theoretically exist on a surface given the right conditions. It holds the distinction of being the second-nearest known exoplanet in a stellar habitable zone, trailing only Proxima Centauri b. However, the article is careful to note that GJ 887 d is significantly more massive than Earth and that its composition is entirely unknown. A high mass could mean a thick gas or water envelope rather than a rocky surface, which would fundamentally change assessments about habitability. The planet's true nature may be resolvable by proposed direct imaging missions such as the Habitable Worlds Observatory, which could potentially capture and analyze light reflected from the planet's atmosphere or surface. Until such a mission flies, the composition and surface conditions of GJ 887 d remain genuinely open questions.
08 A hint of hidden giant from two spacecraft Deeper
Beyond the inner planetary system, there is an intriguing discrepancy lurking in the astrometric data for Lacaille 9352. Measurements of the star's proper motion taken by the Hipparcos spacecraft and those taken later by the Gaia spacecraft do not perfectly agree with each other. When such a disagreement appears, one well-established explanation is the gravitational tug of an unseen outer companion — a large planet or possibly a brown dwarf — that causes the star itself to wobble slightly around the system's center of mass, creating an apparent inconsistency between measurements made at different epochs. Astronomers have flagged this discrepancy as suggestive of an outer giant planet, though it is described as a possibility rather than a confirmed detection. If such a body exists, it would make the Lacaille 9352 system more architecturally complex than current confirmed data alone suggest, and it would raise new questions about how inner super-Earths form and survive alongside distant giant companions.
09 Radial velocity instruments behind the discovery Deeper
The planetary detections at Lacaille 9352 relied on the radial velocity technique, which requires extraordinary precision in measuring a star's spectrum over many observations. The two instruments credited are HARPS — the High Accuracy Radial velocity Planet Searcher, mounted on the ESO 3.6-meter telescope at La Silla Observatory in Chile — and HIRES, the High Resolution Echelle Spectrometer on the 10-meter Keck I telescope at Mauna Kea in Hawaii. Together, these two facilities represent some of the most capable Doppler planet-hunting hardware on Earth. Their data, gathered from opposite hemispheres, were combined to build a detailed picture of the stellar reflex motion caused by orbiting planets. Using two independent instruments also provides a crucial cross-check: a signal that appears in both datasets is far more likely to be a real planetary signal rather than an artifact of one telescope or reduction pipeline. The subsequent 2026 confirmation study demonstrated exactly this kind of iterative, multi-instrument approach to building confidence in a complex planetary system.
10 Its place among the Sun's nearest neighbors
Lacaille 9352 ranks as the twelfth closest star system to our Solar System, sitting at a distance of about 10.72 light-years (3.29 parsecs). Traveling at the speed of a commercial airplane — roughly 900 kilometers per hour — it would take well over ten million years to reach it, which puts its apparent closeness firmly in astronomical rather than human terms. Despite that ranking, it is not part of any well-known grouping like the Alpha Centauri system or the Epsilon Eridani neighborhood; it stands somewhat isolated in Piscis Austrinus. Its nearest stellar companion, the EZ Aquarii triple system, is about 4.1 light-years away, which is itself a substantial interstellar gulf. Being among the dozen closest stellar systems makes Lacaille 9352 a natural target for both current radial velocity surveys and future direct imaging missions, since proximity reduces the angular separation challenges that make studying faint planets so technically demanding.
11 The name behind the catalog designation
The star carries two parallel identifiers used by different catalogs. Its designation as Lacaille 9352 refers to the eighteenth-century French astronomer Nicolas Louis de Lacaille, who conducted an ambitious survey of southern hemisphere stars from the Cape of Good Hope between 1751 and 1752, cataloging nearly ten thousand stars that European observers in the north had never systematically recorded. His work laid the foundation for southern sky catalogs that remained authoritative for generations, and several nearby red dwarfs still carry his name as catalog designations. The alternative identifier, Gliese 887 or GJ 887, comes from the Catalogue of Nearby Stars compiled by Wilhelm Gliese and later expanded by Hartmut Jahreiß, which focuses specifically on stars within roughly 25 parsecs of the Sun. Both names refer to exactly the same star; which one an astronomer uses often simply reflects which catalog their research tradition draws on.
