 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.