Pi Puppis, Latinized from π Puppis, also named Ahadi, is the second-brightest star in the southern constellation of Puppis. It has an

apparent visual magnitude Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's lig ...

of 2.733, so it can be viewed with the naked eye at night. Parallax measurements yield an estimated distance of roughly from the

Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...

. This is a double star with a magnitude 6.86 companion at an angular separation of 0.72 arcsecond and a

position angle In astronomy, position angle (usually abbreviated PA) is the convention for measuring angles on the sky. The International Astronomical Union defines it as the angle measured relative to the north celestial pole (NCP), turning positive into the ...

of 148° from the brighter primary. PiPupLightCurve

The

spectrum A spectrum (plural ''spectra'' or ''spectrums'') is a condition that is not limited to a specific set of values but can vary, without gaps, across a continuum. The word was first used scientifically in optics to describe the rainbow of colors ...

of Pi Puppis matches a stellar classification of K3 Ib. The Ib

luminosity class In astronomy, stellar classification is the classification of stars based on their spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a prism or diffraction grating into a spectrum exhibiting the ...

indicates this a lower luminosity

supergiant Supergiants are among the most massive and most luminous stars. Supergiant stars occupy the top region of the Hertzsprung–Russell diagram with absolute visual magnitudes between about −3 and −8. The temperature range of supergiant stars spa ...

star that has consumed the hydrogen fuel at its core,

evolved Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...

away from the main sequence, and expanded to about 235 times the Sun's radius. The effective temperature of the star's outer envelope is approximately 4,000 K, which gives it the orange hue of a

K-type star In astronomy, stellar classification is the classification of stars based on their spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a prism or diffraction grating into a spectrum exhibiting the ...

. It is a

semiregular variable star In astronomy, a semiregular variable star, a type of variable star, is a giant or supergiant of intermediate and late (cooler) spectral type showing considerable periodicity in its light changes, accompanied or sometimes interrupted by various irre ...

that varies in apparent magnitude from a high of 2.70 down to 2.85. Pi Puppis is the brightest star in the

open cluster An open cluster is a type of star cluster made of up to a few thousand stars that were formed from the same giant molecular cloud and have roughly the same age. More than 1,100 open clusters have been discovered within the Milky Way galaxy, an ...

Collinder 135.

Naming

The star has the traditional name Ahadi, which is derived from Arabic for "having much promise". In

Chinese Chinese can refer to: * Something related to China * Chinese people, people of Chinese nationality, citizenship, and/or ethnicity **''Zhonghua minzu'', the supra-ethnic concept of the Chinese nation ** List of ethnic groups in China, people of ...

, (), meaning '' Bow and Arrow'', refers to an asterism consisting of π Puppis, δ Canis Majoris, η Canis Majoris, HD 63032,

HD 65456 χ Puppis, Latinised as Chi Puppis, is a single star in the southern constellation of Puppis. It has a white hue and is faintly visible to the eye at night with an apparent visual magnitude of 4.79. The star is located at a distance o ...

, ο Puppis, k Puppis, ε Canis Majoris and κ Canis Majoris. Consequently, π Puppis itself is known as (, en, the Ninth Star of Bow and Arrow.)

References

External links

Pi Puppis
{{DEFAULTSORT:Pi Puppis Puppis Puppis, Pi K-type supergiants Ahadi 035264 2773 056855 Durchmusterung objects Triple star systems