News: A fundamental astrophysics distance tool called Cepheid stars are newly discovered to vary in brightness and mass with age.
“Everything crumbles in cosmology studies if you don’t start up with the most precise measurements of Cepheids possible,” said Cepheid research follow-up study lead author Pauline Barmby, of the University of Western Ontario, Canada.
The stars are called Cepheid variables. The “variable” term means that the stars brighten and dim within very strict time and brightness limits, their actual brightness is directly related to how fast they “blink.” This allows us to compare the observed brightness with the “blink” calibrated brightness — making Cepheid variables a very reliable distance tool . . . or so we thought.
The new research found that the pulse rate changes over time probably due to the stars burning up their fuel. This came as a surprise, but probably should have been predicted.
This means the distance to Cepheid stars has a much larger margin of error than previously thought.
The reason this is such a big deal is that the distances to Cepheid stars is perhaps the most fundamental cosmological distance measure; all other cosmology distance measurements use this as a baseline reference tool.
Search for Extended Infrared Emission.
P. Barmby, M. Marengo, N. R. Evans, G. Bono, D. Huelsman, K. Y. L. Su, D. L. Welch, G. G. Fazio. Galactic Cepheids with Spitzer. II. The Astronomical Journal, 2011; 141 (2): 42 DOI: 10.1088/0004-6256/141/2/42
An Infrared Nebula Associated with δ Cephei: Evidence of Mass Loss?
M. Marengo, N. R. Evans, P. Barmby, L. D. Matthews, G. Bono, D. L. Welch, M. Romaniello, D. Huelsman, K. Y. L. Su, G. G. Fazio. The Astrophysical Journal, 2010; 725 (2): 2392 DOI: 10.1088/0004-637X/725/2/2392
“Cosmology Standard Candle Not So Standard After All”