Exploring optical counterparts of protostars and their accretion rates with Gaia DR3

One of the outstanding open questions in the star formation is, when does the star attain most of its mass?

The observed low accretion rates in T-Tauri stars indicate that the time predicted by star formation models to form a star is insufficient, implying either accretion is episodic or accretion rates are higher in the early stages. Hence estimating accretion rates in the early protostellar phases is critically important to resolve this puzzle of star formation, but measuring the same is challenging due to very high extinction for the optical/UV photons along the line of sight. However, due to the lack of envelope mass density symmetry, sometimes it is possible to observe the protostars at the optical wavelengths. Using Gaia DR3's high angular resolution and sensitivity, we have detected over 200 protostars at optical wavelengths in the nearby (d<450 pc) star-forming regions. This study increases the number of optically detected protostars by a factor of 10. The Gaia DR3 additionally gives the H equivalent width (EW-Ha) calculated from the low-resolution BP/RP spectra. Using calibrated EW-Ha, we have estimated the accretion rates of 50 protostars. We will present the results of this study at the symposium.