The article “Astronomers find distant star with a whole set of superEarths” (SN: 7/05/08, p. 7) leaves out some of the most interesting and important information. Is HD 40307 a G-type star like our sun? Which method was used to detect the planets? The article implies Doppler was used, but Doppler could not give the specific masses of planets in the article.
John Myers, San Diego, Calif.
HD 40307 is a K-type star, spectral class K2.5V . You could call this an orange dwarf star. The researchers used the Doppler method. Technically their measurements give minimum masses. The team probably presented these as the actual masses because the researchers believe the angles of inclination of the orbits are close to 90 degrees and therefore the actual masses are close to the minimums. — RON COWEN
Breaking the link
I have observed the link between serious disease and depression — discussed in “Sick and down” (SN: 7/19/08, p. 26) — in two elderly relatives, now deceased. It caused one to engage in self-destructive behaviors and the other to skip medications. In my own case, the link between depression and chronic migraines was broken largely by physical therapy after surgery for repair of a torn ligament. To my astonishment, the depression lifted after about six weeks. Medications were also changed, so the extra exercise alone may not have done the trick. I am convinced it was a big part.
Diana Gainer, Greenville, Texas
Planning for hazards
In regard to “Challenges to building a disaster-resilient nation” (SN: 6/21/08, p. 32), the South Carolina Emergency Management Division — from which I am now retired — and many state counties use Hazards United States Multihazard, or HAZUS-MH, at the state and local levels. We have used this program for many years. We were the first state to update the infrastructure database. Working with FEMA and a consultant, the state is now using a web portal and consolidated data management system to update the infrastructure annually and perform hazards analysis. Planning hazard preparedness, response, recovery and mitigation is an ongoing and important program at SCEMD, state agencies and local governments, and for FEMA.
John Knight, Ridgeway, S.C.