The ‘Forbidden Planet’ That Escaped a Fiery Doom
All across the Milky Way, dying stars are gobbling up their planets. Even Earth is likely to perish this way about five billion years from now, when the sun expands and devours its innermost worlds.
But the giant planet Halla, which closely orbits a star 520 light years from Earth, appears to have narrowly escaped such an apocalyptic fate. A new explanation for this planet’s survivor status hints that there may be a hidden population of death-defying worlds elsewhere in the galaxy, according to a study published on Wednesday in the journal Nature.
Halla is “a forbidden planet of sorts,” said Marc Hon, a NASA Hubble fellow at the University of Hawaii at Manoa and an author of the study. “The star itself might have a very unusual history that somehow permitted this planet to survive at such a close distance around what is otherwise a rather inhospitable host star,” he added.
As stars like the sun reach the end of their lives, they transition into red giants that exponentially puff up in size, incinerating any worlds that fall within their advancing boundaries. Scientists have spotted indirect signs of such planetary engulfments across the galaxy, and a team recently reported the first direct detection of a planet flaming out, as a star consumed it. In some systems, planets may even cannibalize each other, according to another recent study that found evidence of a gas giant that ate a Mercury-size world.
Source: The New York Times
