HD 148427


HD 148427, formally named Timir, is a 7th-magnitude star approximately 230 light-years away in the constellation Ophiuchus. It has a spectral type of K0III/IV, indicating a K-type star that is close to becoming a red giant. While some sources describe it as a subgiant, stellar evolution models suggest it is already on the red giant branch. Its mass is 45% greater than the Sun, and it is three times the size and six times more luminous, although its age is 2.5 billion years, younger than the Sun.

Companion

In August 2009, it was found to have a companion in orbit with a minimum mass of, suggesting it is a gas giant planet, and an orbital period of 331.5 days. An astrometric study in 2020 suggested that this object has a nearly face-on orbit, with a true mass between. This would make it either a brown dwarf or a low-mass red dwarf star, rather than a planet. However, a 2026 study instead found an edge-on orbit, indicating a planetary mass. While this study's measurements are uncertain, they suggest the companion is likely substellar.

Naming

HD 148427 and HD 148427 b were chosen as part of the 2019 NameExoWorlds campaign organised by the International Astronomical Union, which assigned each country a star and planet to be named. HD 148427 was assigned to Bangladesh. The winning name for the star was Timir meaning darkness in the Bengali language, alluding to the star being far away in the darkness of space. The winning name for the companion was Tondra meaning nap in the Bengali language, alluding to the symbolic notion that the object was asleep until discovered.