About this world
HD 101581 b is an Earth-sized planet orbiting HIP 56998, an orange dwarf (type K4/5V) 41.7 light-years from Earth. It is about 0.96 times the size of Earth. It completes an orbit every 4.47 days at 0.046 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 834 K (561 °C): far too hot for liquid water on its surface. By the "cosmic shoreline", its star has probably stripped its atmosphere away, leaving bare rock.
It was discovered in 2025 by transit with Transiting Exoplanet Survey Satellite (TESS). A planet crosses its star and dims it by a tiny, periodic fraction. HIP 56998 has 2 known planets; the others are HD 101581 c.