Name: Belinda Damian
Affiliation: Christ (Deemed to be University), Bangalore
Conference ID : ASI2022_303
Title : Identifying the lowest mass members in the Sigma Orionis star-forming region
Authors : Belinda Damian, Jessy Jose, Beth Biller, Sophie Dubber, Loic Albert, Katelyn Allers, KT Paul
Abstract Type: Poster
Abstract Category : Stars, ISM and Galaxy
Abstract : In star-forming regions, the low-mass brown dwarfs and free-floating planets are vital tracers of the low mass end of star formation and are key analogues to exoplanets around stars. The detection of these young low-mass objects is pivotal in studies of objects in the mass range of exoplanets. These objects provide a laboratory for detailed quantitative study in a context where light from a parent star does not mask the source properties of the planetary-mass object. The complete census of a star-forming cloud, to masses well below the deuterium-burning limit, will also constrain the very low-mass end of the IMF. There have been several attempts in the past to identify and characterize these objects using optical and NIR photometry with the shortcoming that the reddened background field dwarfs occupy the same location as these low-mass cluster members in the color-magnitude diagrams. Additionally, they require significant telescope time to spectroscopically confirm their nature. We present a novel and robust technique to photometrically identify the substellar objects in the nearby young Sigma Orionis star-forming region using the NIR WIRCam data from the 3.6m Canada France Hawaii Telescope (CFHT). This technique uses data from the custom W-band filter (centered at 1.45𝜇m water absorption feature) combined with the data from the J and H broadband filters to classify brown dwarfs based on a reddening insensitive index (Q). The substellar objects thus identified were then spectroscopically followed-up using the SpeX spectrograph on the 3.2m NASA Infrared Telescope Facility (IRTF) and are found to have spectral types M3-M9 yielding a 100% confirmation rate for our novel technique. Studying these brown dwarfs will probe the IMF down to the substellar regime and aid in understanding their formation mechanism for one of the well-known young clusters in the solar neighbourhood for the first time.