Zeta Leporis - Asteroid Belt

Asteroid Belt

A size comparison of the asteroid belt of the Solar System (top) and the Zeta Leporis asteroid belt (bottom).

In 1983, based on radiation in the infrared portion of the electromagnetic spectrum, the InfraRed Astronomical Satellite was used to identify dust orbiting this star. This debris disk is constrained to a radius of 12.2 Astronomical units, or just over twelve times the distance from the Earth to the Sun.

By 2001, the Long Wavelength Spectrometer at the Keck Observatory on Mauna Kea, Hawaii, was used more accurately to constrain the radius of the dust. It was found to lie within a 5.4 AU radius. The temperature of the dust was estimated as about 340 K. Based on heating from the star, this could place the grains as close as 2.5 AU from Zeta Leporis.

It is now believed that the dust is coming from a massive asteroid belt in orbit around Zeta Leporis, making it the first extra-solar asteroid belt to be discovered. The estimated mass of the belt is about 200 times the total in our own asteroid belt, or 4 × 1023 kg. (For comparison, that is more than half the total mass of our Moon.) Astronomers Christine Chen and professor Michael Jura found that the dust contained within this belt should have fallen into the star within 20,000 years, a much shorter time period than Zeta Leporis' estimated age, suggesting that some mechanism must be replenishing the belt. The belt's age is estimated to be 3 × 108 years.

The Zeta Leporis system

Companion	Mass	Semimajor axis	Orbital period	Eccentricity	Radius
Asteroid belt	2.5–6.1 AU