- The Rosseland radius derived from angular measurements of the star's photosphere rather than an extended envelope is.
- Any planets that were orbiting within this radius would have interacted directly with the star's extended envelope.
- The entire star is surrounded by an extended envelope that can be detected by its excess infrared emission,
- In Australia in late 1951, Kerr used a specially built 36-foot transit telescope, the largest dish of its kind in Australia, and started mapping the Magellanic Clouds, discovering considerable amounts of neutral hydrogen and an extended envelope around both clouds.
- Radio interference at that frequency, which coincides with the natural frequency of hydroxyl molecules ( made of hydrogen and oxygen ), masks the very faint signals emitted by interstellar gas clouds and the extended envelopes of red giant stars, among other things.