BD Camelopardalis is an S star and

symbiotic star A symbiotic binary is a type of binary star system, often simply called a symbiotic star. They usually contain a white dwarf with a companion red giant. The cool giant star loses material via Roche lobe overflow or through its stellar wind, whic ...

in the constellation

Camelopardalis Camelopardalis is a large but faint constellation of the northern sky representing a giraffe. The constellation was introduced in 1612 or 1613 by Petrus Plancius. Some older astronomy books give Camelopardalus or Camelopardus as alternative for ...

. It was recognized as a spectroscopic binary star in 1922, and its orbital solution published in 1984; it has a 596-day orbital period. A spectroscopic composition analysis was done of the red giant primary star in 1986.

Description

Although the star's spectrum shows the spectral features of zirconium oxide which define spectral class S, BD Cam shows no technetium lines in its spectrum. It is believed to be an "extrinsic" S star, one whose

s-process The slow neutron-capture process, or ''s''-process, is a series of reactions in nuclear astrophysics that occur in stars, particularly asymptotic giant branch stars. The ''s''-process is responsible for the creation (nucleosynthesis) of approximat ...

element excesses originate in a binary companion star. The system displays only minimal variations in the

visible Visibility, in meteorology, is a measure of the distance at which an object or light can be seen. Visibility may also refer to: * A measure of turbidity in water quality control * Interferometric visibility, which quantifies interference contrast ...

, but the presence of the companion and its interactions with the

stellar wind A stellar wind is a flow of gas ejected from the upper atmosphere of a star. It is distinguished from the bipolar outflows characteristic of young stars by being less collimated, although stellar winds are not generally spherically symmetric. D ...

of the visible

red giant A red giant is a luminous giant star of low or intermediate mass (roughly 0.3–8 solar masses ()) in a late phase of stellar evolution. The outer atmosphere is inflated and tenuous, making the radius large and the surface temperature around or ...

makes for easily observed time-variable spectral features in the

ultraviolet Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nanometer, nm (with a corresponding frequency around 30 Hertz, PHz) to 400 nm (750 Hertz, THz), shorter than that of visible light, but longer than ...

and in the near infrared spectral line of

helium Helium (from el, ἥλιος, helios, lit=sun) is a chemical element with the symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas and the first in the noble gas group in the periodic table. ...

. At times BD Cam is the brightest S star in the visible sky, because other bright S stars are Mira variables or other types of

variable star A variable star is a star whose brightness as seen from Earth (its apparent magnitude) changes with time. This variation may be caused by a change in emitted light or by something partly blocking the light, so variable stars are classified as ...

with large changes in apparent brightness. Its own brightness variability in the visible part of the spectrum is modest.

References

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HR 1105

Image BD Camelopardalis

{{DEFAULTSORT:BD Camelopardalis Camelopardalis Slow irregular variables S-type stars 022649 017296

1105 Year 1105 ( MCV) was a common year starting on Sunday (link will display the full calendar) of the Julian calendar. Events By place Levant * February 28 – Raymond IV (Saint-Gilles) dies at his castle of Mons Peregrinus ("Pilgr ...

Camelopardalis, BD Asymptotic-giant-branch stars BD+62 0597