64 Serpentis is a single, blue-white hued

star A star is an astronomical object comprising a luminous spheroid of plasma (physics), plasma held together by its gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked ...

in Serpens Cauda, the eastern segment of the equatorial

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the e ...

of Serpens. With an apparent visual magnitude of 5.56, it is a dim star but visible to the naked eye in good seeing conditions. Based upon an annual parallax shift of , it is located roughly 1,100

light year A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 1012 ...

s away. It is moving closer to the Sun with a heliocentric

radial velocity The radial velocity or line-of-sight velocity, also known as radial speed or range rate, of a target with respect to an observer is the temporal rate of change, rate of change of the distance or Slant range, range between the two points. It is e ...

of about −10 km/s. It is one of the brightest stars in front of the Great Rift. Over time this star has received a range of

stellar classification In astronomy, stellar classification is the classification of stars based on their stellar spectrum, spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a Prism (optics), prism or diffraction grati ...

s, which varied considerably in the determined luminosity class. Houk and Swift (1999) have it classified as B8/9 II, Slettebak (1982) listed a class of B8 IV, Cowley (1972) has , while Frémat et al. (2006) gave it a classification of B8 III. Despite these assignments, it is still considered to be in the

main sequence In astronomy, the main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Her ...

phase. An overshoot of the convective core due to internal waves and rotational effects are believed to be mixing in fresh hydrogen and removing helium ashes, which is extending the duration of its stay on the main sequence. It may be

chemically peculiar In astrophysics, chemically peculiar stars (CP stars) are stars with distinctly unusual metal abundances, at least in their surface layers. Classification Chemically peculiar stars are common among hot main-sequence (hydrogen-burning) stars. Thes ...

, displaying an overabundance of

mercury Mercury commonly refers to: * Mercury (planet), the nearest planet to the Sun * Mercury (element), a metallic chemical element with the symbol Hg * Mercury (mythology), a Roman god Mercury or The Mercury may also refer to: Companies * Merc ...

(Hg) in its outer atmosphere. 64 Serpentis was observed extensively during the CoRoT mission, which allowed highly accurate monitoring of its brightness. This revealed that the star displays low- amplitude variations with the main frequency being 1.56 days long, while it has smaller variations with other frequencies. These variations may be due to rotational modulation of spots or clouds in the

photosphere The photosphere is a star's outer shell from which light is radiated. The term itself is derived from Ancient Greek roots, φῶς, φωτός/''phos, photos'' meaning "light" and σφαῖρα/''sphaira'' meaning "sphere", in reference to it ...

, or possibly from non-radial pulsations. It does not exhibit the signature of a significant

magnetic field A magnetic field is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experiences a force perpendicular to its own velocity and to ...

. This is a classical Be star – a rapidly rotating B-type main sequence star that has formed an orbiting gaseous disk through a mass ejection process. The circling gas is heated by the star, creating the Balmer line

emission Emission may refer to: Chemical products * Emission of air pollutants, notably: **Flue gas, gas exiting to the atmosphere via a flue ** Exhaust gas, flue gas generated by fuel combustion ** Emission of greenhouse gases, which absorb and emit radi ...

that overlays the

stellar spectrum Astronomical spectroscopy is the study of astronomy using the techniques of spectroscopy to measure the spectrum of electromagnetic radiation, including visible light, ultraviolet, X-ray, infrared and radio waves that radiate from stars and othe ...

. The rapid rotation gives the star an oblate shape with a prominent equatorial bulge. 64 Serpentis is about 170 million years old with roughly 4.4 times the

mass of the Sun The solar mass () is a standard unit of mass in astronomy, equal to approximately . It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxies and black holes. It is approximately equal to the mass ...

and is radiating 724 times the Sun's luminosity from its photosphere at an

effective temperature The effective temperature of a body such as a star or planet is the temperature of a black body that would emit the same total amount of electromagnetic radiation. Effective temperature is often used as an estimate of a body's surface temperature ...

of around 12,000 K.

References

{{DEFAULTSORT:64 Serpentis B-type main-sequence stars Be stars Serpens Durchmusterung objects Serpentis, 64 175869 093051 7158