Astronomy Picture of the Day

Discover the cosmos! Each day we feature a different image or photograph of our fascinating universe, along with a brief explanation written by a professional astronomer.

January 30, 1996

70 Virginis b: A New Water Planet?
Discovery Credit: G. Marcy (SFSU), and P. Butler (UC Berkeley)
Photo Credit: UK Schmidt Telescope, Skyview
Photo Copyright: Royal Observatory Edinburgh, Anglo-Australian Observatory, and AURA

Explanation: The star 70 Virginis has a planet. This recent discovery is the second known case of a planet orbiting a normal star other than our Sun itself. The first case involved 51 Pegasi and was announced last year. The star 70 Vir, shown in the centre of the above false-colour picture, is very much like the Sun. The planet is not visible above - the unusual structure surrounding the star is caused by the telescope. The planet, designated 70 Vir b for short, was discovered by very slight periodic shifts in its colours. Defining characteristics of this planet include that it is at least eight times the mass of Jupiter, it's orbit is much smaller than Jupiter's, and it's temperature allows water to exist in liquid form - like on the Earth. Life on Earth is based on liquid water - could life exist here too?

Tomorrow's picture: Planets Around Sun-Like Stars

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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
NASA Technical Rep.: Jay Norris. Specific rights apply.
A service of: LHEA at NASA/ GSFC
&: Michigan Tech. U.