This extended range should permit astronomers to calibrate the brightnesses of Cepheid variable stars (used as "standard candles" for gauging the distances of other galaxies) and of relatively old
subdwarf stars (allowing better distance estimates to globular clusters).
Prof Warner attended the conference "Hot
Subdwarf Stars and related Objects" in Bamberg (D) in July 2007 and gave the conference summary.
Hot
Subdwarfs in Bamberg, in Hot
Subdwarf Stars and Related Objects, eds.
For sorting by mass, we suggest the categories
subdwarf, dwarf, subgiant, giant, and supergiant.
The stellar classes discussed in detail at the conference include R Coronae Borealis stars, extreme helium stars, Wolf-Rayet central stars of planetary nebulae, white dwarfs, and helium-rich
subdwarf O and B stars.
There are some key differences between the sun and V391 Pegasi, which is now a B-type
subdwarf. Like other stars of this rare class, it reached its present state by following an unusual evolutionary path, Silvotti notes.
Hot
subdwarf stars represent several stages in the very late evolution of low-mass stars.
This is farther than many of the Milky Way's nearest galactic neighbors, suggesting that this particular
subdwarf may have originated somewhere else.
Today it's a very hot, type-B
subdwarf: the core remaining from a red giant that has lived out its life and shed the bulk of its material back to space.
Conference on Hot
Subdwarf Stars and Related Objects (6th: 2013: Tucson, Arizona) Edited by V.
Topics examined include the H1 distribution of the Milky Way; progenitors of core-collapse supernovae; gravitational waves from merging compact binaries; physical properties and environments of nearby galaxies; hot
subdwarf stars; high-contrast observations in optical and infrared astronomy; magnetic reconnection in astrophysical and laboratory plasmas; magnetic fields of nondegenerate stars; star-formation histories, abundances, and kinematics of dwarf galaxies in the local group; complex organic interstellar molecules; the chemical composition of the sun; teraelectronvolt astronomy; and the study of gamma-ray bursts in the era of the Swift satellite.
But sometimes, the giant sheds its stellar skin before contracting, leaving behind a bright, beating heart--the hot B
subdwarf. Scientists hypothesize that a companion star or planet might instigate the transformation.