HD 85512 is a solitary

K-type main-sequence star A K-type main-sequence star, also referred to as a K-type dwarf, or orange dwarf, is a main-sequence (hydrogen-burning) star of spectral type K and luminosity class V. These stars are intermediate in size between red M-type main-sequence stars ...

away in the constellation Vela. It is about 1 billion years older than the

Sun The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...

. It is extremely chromospherically inactive, only slightly more active than

Tau Ceti Tau Ceti, Latinized from τ Ceti, is a single star in the constellation Cetus that is spectrally similar to the Sun, although it has only about 78% of the Sun's mass. At a distance of just under from the Solar System, it is a relativ ...

. It exhibits a long-term variability and was thought to host one low-mass planet, although this is now doubtful.

Proposed planetary system

On August 19, 2011, a ≥3.6 Earth-mass planet was discovered using

HARPS The High Accuracy Radial Velocity Planet Searcher (HARPS) is a high-precision Echelle grating, echelle planet-finding spectrograph installed in 2002 on the ESO 3.6 m Telescope, ESO's 3.6m telescope at La Silla Observatory in Chile. The First l ...

that is "just inside" the

habitable zone In astronomy and astrobiology, the habitable zone (HZ), or more precisely the circumstellar habitable zone (CHZ), is the range of orbits around a star within which a planetary surface can support liquid water given sufficient atmospheric pressu ...

, along with the inner planets of e (or 82 G.) Eridani, and HD 192310 c in Capricornus. These two other systems are closer to Earth than this system. Modelling at the time of the discovery announcement found that the planet could be cool enough to host liquid water if it has more than 50% cloud coverage, but with revised models of the habitable zone two years later it was found to be too hot to be potentially habitable. For a time it ranked fifth-best for habitability in the

Planetary Habitability Laboratory The Planetary Habitability Laboratory (PHL) is a research remote laboratory intended to study the habitability of the Solar System and other stellar systems, specifically, potentially habitable exoplanets. The PHL is managed by the University of ...

's Habitable Exoplanets Catalog, which later listed it in an article about "false starts" in the search for potentially habitable exoplanets. In 2023, a study reassessed the

radial velocity The radial velocity or line-of-sight velocity of a target with respect to an observer is the rate of change of the vector displacement between the two points. It is formulated as the vector projection of the target-observer relative velocity ...

data of HD 85512. A signal was detected with a period of 51 days, inconsistent with the previously published 58-day orbital period of HD 85512 b, but consistent with previous estimates of the stellar rotation period. This indicates that the signal is very likely to be caused by the stellar rotation, rather than an orbiting planet. Due to this, the

NASA Exoplanet Archive The NASA Exoplanet Archive is an online astronomical exoplanet catalog and data service that collects and serves public data that support the search for and characterization of extra-solar planets (exoplanets) and their host stars. It is part of ...

now considers this planet as a false positive detection.

References

Notes

External links

* {{DEFAULTSORT:HD 85512 Vela (constellation) 085512 048331 0370 K-type main-sequence stars Hypothetical planetary systems Durchmusterung objects J09510700-4330097