Scientists on the hunt for planetary formation fossils reveal unexpected eccentricities in nearby debris disk

Using the Atacama Large Millimeter/submillimeter Array (ALMA), astronomers have imaged the debris disk of the nearby star HD 53143 at millimeter wavelengths for the first time, and it looks nothing like they expected. Based ...

HD 53143—a roughly billion-year-old sun-like star located 59.8 light-years from Earth in the Carina constellation— was first observed with the coronagraphic Advanced Camera for Surveys on the Hubble Space Telescope (HST) in 2006. It also is surrounded by a debris disk—a belt of comets orbiting a star that are constantly colliding and grinding down into smaller dust and debris—that scientists previously believed to be a face-on ring similar to the debris disk surrounding our sun, more commonly known as the Kuiper Belt.

The new observations were made of HD 53143 using the highly sensitive Band 6 receivers on ALMA, an observatory co-operated by the U.S. National Science Foundation's National Radio Astronomy Observatory (NRAO), and have revealed that the star system's debris disk is actually highly eccentric. In ring-shaped debris disks, the star is typically located at or near the center of the disk. But in elliptically shaped eccentric disks, the star resides at one focus of the ellipse, far away from the disk's center. Such is the case with HD 53143, which wasn't seen in previous coronagraphic studies because coronagraphs purposely block the light of a star in order to more clearly see nearby objects. The star system may also be harboring a second disk and at least one planet.

Artist’s impression of the billion-year-old Sun-like star, HD 53143, and its highly eccentric debris disk. The star and a second inner disk are shown near the southern foci of the elliptical debris disk. A planet, which scientists assume is shaping the disk through gravitational force, is shown to the north. Debris disks are the fossils of planetary formation and since we can’t directly study our own disk— also known as the Kuiper Belt— scientists glean information about the formation of our Solar System by studying those we can see from a distance. Credit: ALMA (ESO/NAOJ/NRAO); M. Weiss (NRAO/AUI/NSF) Read more

While studying HD 53143— a roughly billion-year-old Sun-like star— in millimeter-wavelengths for the first time, scientists discovered that the star’s debris disk is highly eccentric. Unlike ring-shaped debris disks, in which the star sits in the center, HD 53143 is located at one foci of an elliptical-shaped disk, and is shown as the unresolved dot below and left of center. Scientists believe a second unresolved dot in the north of this image to be a planet that is perturbing and shaping the debris disk. Credit: ALMA (ESO/NAOJ/NRAO), M. MacGregor (U. Colorado Boulder), S. Dagnello (NRAO/AUI/NSF) Read more

Composite image of the HD 53143 star system. Shown in orange/red, millimeter-wavelength data from Atacama Large Millimeter/submillimeter Array (ALMA), reveal a previously unobserved eccentric debris disk orbiting HD 53143 in the form of an ellipse. Am unresolved dot shows the star off-center near the southern foci of the disk, while a second unresolved dot to the north indicates the potential presence of a planet. Optical data from the Hubble Space Telescope’s Advanced Camera for Surveys (ACS) is shown in blue and white; a coronagraphic mask blocks out the starlight, allowing researchers to see what’s happening in the region surrounding HD 53143. Credit: ALMA (ESO/NAOJ/NRAO), M. MacGregor (U. Colorado Boulder), S. Dagnello (NRAO/AUI/NSF) Read more

HD 53143 is located in the Carina constellation, roughly 59.8 light-years from Earth. Credit: IAU/Sky & Telescope Read more