- evn2024@mpifr.de
Support
Contribution
Dynamical Masses of Young Stellar Multiple Systems with the VLBA (DYNAMO-VLBA)
Speakers
- Jazmín ORDÓÑEZ-TORO
Primary authors
- Jazmín ORDÓÑEZ-TORO (Institute of Radio Astronomy and Astrophysics (IRyA), UNAM)
Co-authors
- Sergio Abraham DZIB QUIJANO ()
- Laurent LOINARD (IRyA, UNAM)
Files
Content
Very Long Baseline Interferometry (VLBI) provides high angular resolution images and has been used for stellar astrometry for decades. In the DYNAMO-VLBA project, we utilize the Very Long Baseline Array (VLBA) to study tight binary and multiple pre-main-sequence stars, whose components have detectable radio emission and typical separations on the order of milli-arcseconds. Consequently, Gaia cannot provide information on their orbital parameters, making VLBA observations essential for ongoing study. We report dynamical mass measurements of the individual stars in the S1 system in Ophiuchus and EC95 in Serpens. S1 is the most luminous and massive stellar member of the nearby Ophiuchus star-forming region. We found that the primary component, S1A, has a mass of 4.11 ± 0.10 M⊙ , significantly less than the previously reported 6 M⊙, highlighting a discrepancy where the models corresponding to S1A's HR diagram location predict masses at least 25% higher than the dynamical mass. The secondary, S1B, has a mass of 0.831 ± 0.014 M⊙. Additionally, we detected the secondary component during periastron for the first time. In the triple system EC95 in the Serpens region, we measured the masses of EC95A and EC95B, finding 2.148 ± 0.097 M⊙ and 1.998 ± 0.116 M⊙, respectively. For the first time, we estimated the mass of EC95C to be 0.192 ± 0.545 M⊙ with a period of 179.3 ± 20.1 years. The dynamical mass estimations derived from VLBA data are free of assumptions on the physical parameters of the stars and could be used to test evolutionary models of pre-main-sequence stars.