It is a combination of the pentatonic scale Chandrakauns of Hindusthani music and the sampurna raga scale Keeravani.
[1][2] Kalyanavasantam is an asymmetric rāgam that does not contain rishabham or panchamam in the ascending scale.
[1][2] Its ārohaṇa-avarohaṇa structure (ascending and descending scale) is as follows: The notes used in this scale are shadjam, sadharana gandharam, shuddha madhyamam, shuddha dhaivatham and kakali nishadham in ascending scale, with panchamam and chathusruthi rishabham included in descending scale.
For the details of the notations and terms, see swaras in Carnatic music.
(Ragam Srothoswini touches also) This section covers the theoretical and scientific aspect of this rāgam.