A few years ago, the Hubble telescope captured a stunning image in the Serpens Nebula, which appeared to have a huge bat-shaped shadow. Subsequent observations suggest that it appears to be flapping its wings, suggesting that it may have been affected by nearby planets. It is reported that “Bat Shadow” is due to a star projection called HBC 672, about 1400 light-years from Earth, the extension length of about 200 times the solar system.
(Photo: NASA / ESA / STScl)
The researchers believe the shadow is caused by a fluffy disk of dust around HBC 672, which may block light from passing through the upper and lower sides of the star.
After 404 days of taking the first image, Hubble recently re-targeted the lens, only to find that the position and shape of the wings had changed, and the contrast felt like they were pouncing.
Although it is not clear what caused it, the team speculated that the disc was not flat enough and was itself bent in a saddle. As it rotates around the star, it emits light in different directions, creating a shadowy effect of flapping its wings.
(Pictured from: A. James and G. Bacon)
“If there’s only a simple bulge on the disc, both sides of the shadow tilt in the opposite direction, like the wing of an airplane when turning,” says Colette Salyk.
Guess that the disk may be distorted by an invisible companion star near HBC 672, and a planet with an orbit tilted over the disk plane is enough to do just that. Circle a star every 180 or more years, similar to the Earth orbiting the sun.
Zooming Into the Bat Shadow and its Flapping (via)
It may also be a smaller star on the outside of the disk, causing HBC 672 to swing up and down relative to the dust disk. In the bat Shadow case, however, the team was more likely to be affected by a planet.
Details of the study have been published in the recently published Journal of Astrophysics under the headline “Variability of the Great Disk Shadow in Serpens.”