Kappa Serpentis, Latinised from κ Serpentis, is a single, red-hued star in the constellation Serpens, in its head (Serpens Caput). It has the proper name Gudja and the Flamsteed designation 35 Serpentis. This star is visible to the naked eye with an apparent visual magnitude of +4.09. It is located approximately 383 light years from the Sun, based on parallax, and is drifting closer with a radial velocity of −38 km/s.
This object is an aging red giant star with a stellar classification of M0.5III. After exhausting the supply of hydrogen at its core, the star cooled and expanded off the main sequence, and now has around 71 times the Sun's radius. It is radiating nearly 1,000 times the luminosity of the Sun from its photosphere at an effective temperature of 3,863 K. This is a suspected variable star.
κ Serpentis (Latinised to Kappa Serpentis) is the star's Bayer designation.
The star bore the traditional name Gudja in the culture of the Wardaman people of the Northern territory of Australia, meaning 'water goanna'. In 2016, the IAU organized a Working Group on Star Names (WGSN) to catalog and standardize proper names for stars. The WGSN approved the name Gudja for this star on 10 August 2018 and it is now so included in the List of IAU-approved Star Names.