Kappa Serpentis

Kappa Serpentis (κ Ser / 35 Serpentis / HD 141477 / HR 5879) is a star of apparent magnitude +4.11. Located in the constellation of Serpens in Serpens Caput - the head of the serpent -, it is 348 light years from the Solar System.

Kappa Serpentis is a red giant of spectral type M0.5III. The measurement of its angular diameter, together with its distance, allows the estimation of a diameter 71 times larger than the solar diameter and a temperature of 3575 K, significantly lower than expected by its spectral type. On the other hand, considering a temperature more typical of 3800 K, its diameter would be 66 times greater than the solar diameter and its luminosity would be equivalent to 820 soles. Its mass is between 2 and 2.5 solar masses, depending on the temperature considered.

In either case, Kappa Serpentis is at a peak of luminosity before beginning the fusion of helium into carbon and oxygen; from that moment its brightness and its size will diminish as the helium is transformed. Although these types of stars may be unstable, there is no firm evidence for the variability of Kappa Serpentis.

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