Epsilon Eridani: an early solar system?Among the handful of young stars known to be encircled en·cir·cle tr.v. en·cir·cled, en·cir·cling, en·cir·cles 1. To form a circle around; surround. See Synonyms at surround. 2. To move or go around completely; make a circuit of. by thinning rings of dust--a signpost of planet formation--one nearby star stands out from the rest. New observations reveal that Epsilon Eridani Epsilon Eridani (ε Eri / ε Eridani) is a notable main-sequence K2 class star in the constellation of Eridanus. At 10.5 light years from the Solar System, it is one of the nearest stars visible to the naked eye. may have a planetary system similar to our own. In age, mass, and the position of its newly discovered dust ring, the star bears a close resemblance to what the solar system is thought to have looked like when it was just a few hundred million years old. Examining the star by light emitted at submillimeter wavelengths, astronomers have found a ring of dust at roughly the same distance at which the Kuiper belt, a reservoir of comets, orbits the sun. A bright spot within the ring could represent a dense patch of dust trapped by the gravity of an unseen planet, says Jane S. Greaves greaves cracklings, an edible raw fat from the meat trade. The skimmings from the preparation of this fat are also called greaves. They represent a low grade of meat meal. of the Joint Astronomy Centre The Joint Astronomy Centre (JAC) operates British, Canadian and Dutch telescopes at Mauna Kea Observatory, and provides support for other telescopes and public outreach activities. Since 2006, the JAC has also maintained the Starlink Project. in Hilo, Hawaii. Greaves and her colleagues observed the star with a high-resolution camera attached to the James Clerk Maxwell Telescope The James Clerk Maxwell Telescope (JCMT) is a 15-metre submillimetre-wavelength telescope at Mauna Kea Observatory in Hawaii. It is the largest astronomical telescope in the world designed specifically to operate in the submillimetre regime (between the far-infrared and the atop Mauna Kea in Hawaii. Although comets radiate ra·di·ate v. 1. To spread out in all directions from a center. 2. To emit or be emitted as radiation. ra too faintly at submillimeter wavelengths to be seen, she notes, collisions of comets could generate a dust ring like the one her team found. "What we see looks like the comet belt on the outskirts of our solar system, only younger," says Greaves. She notes that the region inside the ring is relatively dust-free, but it still has 1,000 times as much material as the inner part of the present-day solar system. The new images of the star fit with the standard model of the early solar system at a time when most dust had coalesced co·a·lesce intr.v. co·a·lesced, co·a·lesc·ing, co·a·lesc·es 1. To grow together; fuse. 2. To come together so as to form one whole; unite: into planets, but "there was still lots of stuff whizzing around and impacting the Earth," Greaves says. Visible to the naked eye, Epsilon Eridani lies only 10 light-years from the solar system and is nearly as massive as the sun. At 500 million to 1 billion years old, it is a youngster compared with the 4.5-billion-year-old sun but still old enough to have fully formed planets. In contrast, three other stars now known to have dust rings--Vega, Fomalhaut, and Beta Pictoris--are much younger and more massive than the sun (SN: 4/25/98, p. 260). Greaves reported the findings last month in Santa Barbara, Calif., at a conference on protostars and planets. She and her collaborators will also describe the observations in an upcoming Astrophysical Journal Letters. |
|
||||||||||||||||||||
Printer friendly
Cite/link
Email
Feedback
Reader Opinion