The Core - Wing Anomaly of Cool Ap Stars ? Abnormal Balmer Pro
نویسنده
چکیده
The prooles of H in a number of cool Ap stars are anomalous. Broad wings, indicative of temperatures in the range 7000-8000K end abruptly in narrow cores. The widths of these cores are compatible with those of dwarfs with temperatures of 6000K or lower. This pro-le has been known for Przybylski's star, but it is seen in other cool Ap's. The H proole in several of these stars shows a similar core-wing anomaly (CWA). In Przybylski's star, the CWA is probably present at higher Balmer members. We are unable to account for these prooles within the context of LTE and normal dwarf atmospheres. We conclude that the atmospheres of these stars are not \nor-mal." This is contrary to a notion that has long been held.
منابع مشابه
Abnormal Balmer Profiles
The profiles of Hα in a number of cool Ap stars are anomalous. Broad wings, indicative of temperatures in the range 7000-8000K end abruptly in narrow cores. The widths of these cores are compatible with those of dwarfs with temperatures of 6000K or lower. This profile has been known for Przybylski’s star, but it is seen in other cool Ap’s. The Hβ profile in several of these stars shows a simila...
متن کاملA Rare Congenital Anomaly of Wing in a Pigeon Chick (Columba livia)
Case Description- A 20-day-old pigeon chick with left wing distal to the carpal joint into left flank presented to our avian medicine and surgery clinic. Clinical Findings-The bird had a mal-shaped wing structure, whereas the axial skeleton, thoracic and pelvic limbs skeleton were normal radiographically and clinically, excluding the left wing. The only clinical sign observed was recumbency. Tr...
متن کاملOn the anomaly of Balmer line profiles of A-type stars
In previous work, Gardiner et al. (1999) found evidence for a discrepancy between the Teff obtained from Balmer lines with that from photometry and fundamental values for A-type stars. An investigation into this anomaly is presented using Balmer line profiles of stars in binary system with fundamental values of both Teff and log g. A revision of the fundamental parameters for binary systems giv...
متن کاملA search for radial magnetic field gradients in Ap atmospheres
For the first time the possible presence of radial gradients of magnetic fields in the atmospheres of three magnetic Ap stars has been critically examined by measurements of the mean magnetic field modulus from spectral lines resolved into magnetically split components lying on the different sides of the Balmer jump. A number of useful diagnostic lines below and above the Balmer discontinuity, ...
متن کاملThe calcium isotopic anomaly in magnetic CP stars ⋆
Chemically peculiar stars in the magnetic sequence can show the same isotopic anomaly in calcium previously discovered for mercury-manganese stars in the non-magnetic sequence. In extreme cases, the dominant isotope is the exotic 48 Ca. Measurements of Ca lines arising from 3d-4p transitions reveal the anomaly by showing shifts up to 0.2 Å for the extreme cases—too large to be measurement er...
متن کامل