# # Program information file # PROGRAM_ID 2023A029 PROGRAM_TITLE Investigating the evolution of the young triple system, PDS 11 using SpeX PROGRAM_INV1 Mayank Narang PROGRAM_INV2 Manoj Puravankara PROGRAM_INV3 Himanshu Tyagi PROGRAM_INV4 Bihan Banerjee PROGRAM_INV5 Prasanta Nayak PROGRAM_SCICAT stellar PROGRAM_ABSTRACT_BEG Binary systems provide us with an excellent opportunity to study the formation and evolution of planetary systems in extreme environments. The interaction of close companions leads to not just a rapid disk evolution but also modulates the mass accretion rates onto the stars. To study the effects of separation in binaries on stellar evolution, we will carry out a systematic spectroscopic study of the isolated high galactic Triple T-Tauri system PDS 11. The PDS 11 system is a peculiar system with the most massive component PDS 11C is still embedded and displaying large NIR excess compared to PDS 11 A and B. This result goes against the standard paradigm of disk evolution, thus making the system an excellent laboratory for studying the effects of stellar multiplicity on disk evolution and mass accretion rates. Using SpeX we will observe the three components of the PDS 11 system from 0.7 - 5.3 microns. We will spectral type these sources and study the mass accretion rates and mass outflow rates from the components. With the excellent NIR coverage of SpeX, we will detect the CO fundamental and band heads and use them to determine the temperature and density of the protoplanetary disk. Further, by comparing the mass accretion rates and the physical properties of the disk with other T-Tauri stars, we will gain important insights into how accretion rates are affected by closely interacting companions. PROGRAM_ABSTRACT_END