55 Cancri e (abbreviated 55 Cnc e, also known as Janssen / ˈ dʒ æ n s ən /) is an exoplanet orbiting a Sun-like host star, 55 Cancri A. The mass of the exoplanet is about eight Earth masses and its diameter is about twice that of the Earth.

2024年10月24日 · 55 Cancri e is a super Earth exoplanet that orbits a K-type star. Its mass is 7.99 Earths, it takes 0.7 days to complete one orbit of its star, and is 0.01544 AU from its star. Its discovery was announced in 2004.

A light curve of 7.5- to 11.8-micron light captured by NASA’s James Webb Space Telescope’s MIRI (Mid-Infrared Instrument) in March 2023 shows the decrease in brightness of the 55 Cancri system as the rocky planet 55 Cancri e moves behind the star, a phenomenon known as a secondary eclipse.

2017年7月28日 · 55 Cancri e is a super-Earth — about twice our planet's size — that zooms around its star in 18 days. It has a surface temperature of nearly 4,900 degrees Fahrenheit (2,700 degrees Celsius).

2024年5月8日 · 55 Cancri e is a super-Earth planet that appears composed of diamond-like carbon — now, thanks to the JWST, astronomers have found the world has "grown" a second atmosphere.

2024年1月11日 · New Webb data suggests that the hot super-Earth 55 Cancri e has an atmosphere, perhaps maintained by the planet’s magma ocean. One artist's illustration of 55 Cancri e shows a planet covered in lava flows, with only a wisp of rock-vapor for an atmosphere.

2011年9月25日 · At just 40 light years away, 55 Cancri e stands as the smallest transiting super-Earth in our stellar neighborhood. In fact, 55 Cancri is so bright and close that it can be seen with the naked eye on a clear, dark night.

NASA explores the unknown in air and space, innovates for the benefit of humanity, and inspires the world through discovery. Soar above an ocean of lava amid the sparkling clouds of 55 Cancri e.

2022年5月26日 · Illustration showing what exoplanet 55 Cancri e could look like, based on current understanding of the planet. 55 Cancri e is a rocky planet with a diameter almost twice that of Earth orbiting just 0.015 astronomical units from its Sun-like star.

2024年5月8日 · Researchers using the NASA/ESA/CSA James Webb Space Telescope may have detected atmospheric gases surrounding 55 Cancri e, a hot rocky exoplanet 41 light-years from Earth. This is the best evidence to date for the existence of a rocky planet atmosphere outside our Solar System.