All authors of the article, published in Science, are the University of Warsaw employees: 'A three-dimensional map of the Milky Way using classical Cepheid variable stars
Space Telescope Science said that this particular star is one of the most luminous in the class of Cepheid variable stars
. Over a six-week cycle, it brightens and dims gradually, and its average intrinsic brightness is 15,000 times greater than the Sun's luminosity.
The new value, which lies between 66.2 and 68.4 kilometers per second per megaparsec, is consistent with the value derived from the Planck mission's measurements of the cosmic background radiation, but it's still lower than that obtained from observations of Cepheid variable stars
and Type la supernovae.
To reach farther, scientists use two types of objects of known brightness: Cepheid variable stars
and type la supernovas.
Oscillations occur not only in mechanical systems but also in dynamic systems in virtually every area of science: for example the beating human heart, business cycles in economics, predator-prey population cycles in ecology, geothermal geysers in geology, vibrating strings in musical instruments, periodic firing of nerve cells in the brain, and the periodic swelling of Cepheid variable stars
This portion of the electromagnetic spectrum has numerous advantages, especially when observing Cepheid variable stars
, the so-called "standard candles" that are used to determine distances to distant galaxies.
We present analysis of two double model Cepheid variable stars
, BQ Serpens and VX Puppis.
Since the launch of NASA's Hubble Space Telescope in 1990, the team has observed 18 galaxies up to 65 million light years away and discovered almost 800 Cepheid variable stars
, a special class of pulsating star used for accurate distance measurement.
This didn't mean astronomers clung to the notion that we were "special." The distances to all other galaxies, hence their deduced physical sizes, would double in the 7950s following Walter Baade's landmark reevaluation of how Cepheid variable stars
are used as distance indicators.
Caption: Astronomers measure distance to faraway galaxies--a key to the Hubble constant--by recording the brightness of supernovas and Cepheid variable stars
. In this Hubble telescope image of galaxies NGC 4038/4039, Cepheids are circled in red, blue or green depending on their period.
All Cepheid variable stars
of a given type that vary at a specific rate have the same inherent brightness.
This was, more or less, how Tom Osypowski introduced me to V42 and V84, M5's two Type II Cepheid variable stars
, at the 2013 Golden State Star Party.