# # Program information file # PROGRAM_ID 2023B034 PROGRAM_TITLE Infrared line analysis of Transition Phase candidates: stars in transition from pre-main sequence to main sequence phase PROGRAM_INV1 Suman Bhattacharyya PROGRAM_INV2 Blesson Mathew PROGRAM_INV3 Shridharan Baskaran PROGRAM_INV4 Gourav Banerjee PROGRAM_INV5 Nidhi Sabu PROGRAM_SCICAT stellar PROGRAM_ABSTRACT_BEG In a recent study, a sample of 98 rare stars have been identified which are possibly undergoing transition from pre-main sequence [PMS] to main sequence [MS] phases. Termed as 'Transition Phase' [TP] candidates, these stars fall in a region between PMS Herbig Ae/Be [HAeBe] and MS classical Be [CBe] stars and might be connected to both of these categories through evolutionary phase. Although several studies have been done to better understand the disk characteristics of HAeBe and CBe stars, no study exists till now to understand the properties of even a single TP candidate. We, therefore, propose to perform a detailed near-IR emission line analysis of a selected sample of 31 TP candidates using the SpeX SXD instrument mounted at IRTF facility. The obtained spectra in a wide range [0.7 -- 2.5 micron] will exhibit different spectral series providing the opportunity to perform line analysis of various features to understand the connection between the HAeBe and CBe stars. Detail study of the Paschen line ratio will also be performed along with line ratio analysis for Brackett series to understand the disk opacity in case of TP candidates. PROGRAM_ABSTRACT_END