NASA's Hubble telescope discovers shadow play, may point to a new planet 192 light-years away

NASA’s Hubble telescope has discovered a shadow play that sweeps across the face of a gas and dusk disk, which is shaped like a vast pancake and surrounds a young star. This finding points towards a new planet which is located 192 light-years away, according to scientists.

Though the shadow is not casted by the planet itself, it does some heavy lifting as it pulls on material gravitationally neat the star and warps the disk’s inner part, said researchers.

The shadow across the surface of the outer disk is that of the twisted, misaligned inner disk.

John Debes of the Space Telescope Science Institute in in the US led a team of astronomers who said this scenario is the most plausible explanation for the shadow they found in the stellar system TW Hydrae. It is located 192 light-years away in the constellation Hydra, also known as the Female Water Snake.

Roughly 8 million-years-old, the star is slightly less massive than the Sun.

The researchers were studying NASA’s Hubble Space Telescope’s 18 years’ worth of archival observations when they discovered the phenomenon.

“This is the very first disk where we have so many images over such a long period of time, therefore allowing us to see this interesting effect,” Debes said.

“That gives us hope that this shadow phenomenon may be fairly common in young stellar systems,” he said.

Brightness in the disk which changed with position was the first clue of Debes to the phenomenon. Astronomers first spotted this brightness asymmetry in 2005 using Hubble’s Space Telescope Imaging Spectrograph (STIS) first noted this brightness asymmetry in 2005.

However, they could not make a definitive determination about the nature of the mystery feature as they had only one set of observations.
Researchers stitched six images from several different epochs while searching the archive.

STIS and Hubble’s Near Infrared Camera and Multi-Object Spectrometer (NICMOS) made the observations.

The Hubble looks as close to the star as Saturn is to Sun because of the equipment of the STIS with a coronagraph that blocks starlight to within about 1 billion miles from the star.

Over time, the structure appeared to move in counterclockwise fashion around the disk, until in 2016, it was in the same position as it was in images taken in 2000.

This 16-year period puzzled the researchers. They originally thought the feature was part of the disk, but the short period meant that the feature was moving way too fast to be physically in the disk.

The disks rotate at glacial speeds under the laws of gravity. It would take centuries for the outermost parts of the TW Hydrae disk to complete one rotation.

“The fact that I saw the same motion over 10 billion miles from the star was pretty significant, and told me that I was seeing something that was imprinted on the outer disk rather than something that was happening directly in the disk itself,” Debes said.

“The best explanation is that the feature is a shadow moving across the surface of the disk,” he said. 

(With inputs from PTI)