Flying "Moth" Star

Astronomers studying our corner of the galaxy have found a strange object that looks like a moth spreading its wings and a never before seen system of four tightly grouped stars. The first of these phenomena, dubbed the Moth, is a disk of dust and gas illuminated by a young star in the constellation Puppis. Such disks, believed to be made of the material from which planets form, are common around young stars.

But this one is oddly bent, as though flying into a headwind, and that's exactly what it's doing. Dust grains normally orbit in a plane unless they're disturbed by something, But in this case, the star and its disk are plowing through an interstellar gas cloud. That produces a local wind that is blowing the dust backward, producing this meniscus-like or crescent shape.

The Moth was found as part of a systematic search for planet-forming disks that might shed light on how planetary systems, including our own, formed.

About 112 light-years from the sun, the Moth was detected because of the intense infrared light it emits. One of the things that drew us to this star system is how bright it is in the infrared. That intense radiation indicates the presence of an unusually large amount of dust. The dust is heated by the light from its host star [is heated].

The scientists were surprised that there was enough interstellar gas and dust to produce this effect, because our region of the galaxy is generally believed to be relatively gas free.

Another odd finding: a unique quadruple star system that packs four stars into a region smaller than the orbit of Jupiter. The stars are grouped into two closely spaced pairs, 12 and 50 million miles (20 and 80 million kilometers) apart, respectively. It's really quite amazing that four stars all orbit each other at this distance.

It's not possible for all four stars to have formed that closely together. Rather, they must have formed at greater distances and then spiraled together as interstellar gas slowed their orbits. The gas is now gone, leaving the stars.

There is no reason to believe that the system is actually young, but the stars must have moved close together within the first 100,000 years or so of their lives because soon after, within the first 300,000 or 400,000 years, the gas all dissipates.

The two pairs revolve around each other about once every nine Earth years. The star system lies near the constellation Aquarius, about 166 light-years from Earth.

The study found it while studying the spectra of small, dim, stars relatively close to Earth. The newfound system seemed unusual because it appeared to emit four spectra superimposed on each other.