The HD 98800 quadruple pre-main sequence system. Towards full orbital characterisation using long-baseline infrared interferometry

Abstract

HD 98800 is a young ($\sim 10$ Myr old) and nearby ($\sim 45$ pc) quadruple system, composed of two spectroscopic binaries orbiting around each other (AaAb and BaBb), with a gas-rich disk in polar configuration around BaBb. While the orbital parameters of BaBb and AB are relatively well constrained, this is not the case for AaAb. A full characterisation of this quadruple system can provide insights on the formation of such a complex system. The goal of this work is to determine the orbit of the AaAb subsystem and refine the orbital solution of BaBb using multi-epoch interferometric observations with the VLTI/PIONIER and radial velocities. The PIONIER observations provide relative astrometric positions and flux ratios for both AaAa and BaBb subsystems. Combining the astrometric points with radial velocity measurements, we determine the orbital parameters of both subsystems. We refined the orbital solution of BaBb and derived, for the first time, the full orbital solution of AaAb. We confirmed the polar configuration of the circumbinary disk around BaBb. From our solutions, we also inferred the dynamical masses of AaAb ($M_{Aa}=0.93\pm 0.09$ and $M_{Ab}=0.29\pm 0.02$ M${}_{\odot }$). We also revisited the parameters of the AB outer orbit. Using the N-body simulation, we show that the system should be dynamically stable over thousands of orbital periods and that it made preliminary predictions for the transit of the disk in front of AaAb which is estimated to start around 2026. We discuss the lack of a disk around AaAb, which can be explained by the larger X-ray luminosity of AaAb, promoting faster photo-evaporation of the disk. High-resolution infrared spectroscopic observations would provide radial velocities of Aa and Ab (blended lines in contemporary observations), which would allow us to calculate the dynamical masses of Aa and Ab independently of the parallax of BaBb.

Accepted for publication in Astronomy \& Astrophysiscs journal (01/09/2021)

References in corpus (17)

• The Gaia mission
• New evolutionary models for pre-main sequence and main sequence low-mass stars down to the hydrogen-burning limit
• VOSA: Virtual Observatory SED Analyzer. An application to the Collinder 69 open cluster
• Tertiary companions to close spectroscopic binaries
• Speckle interferometry at SOAR in 2012 and 2013
• Comparative statistics and origin of triple and quadruple stars
• Misaligned gas discs around eccentric black-hole binaries and implications for the final-parsec problem
• A circumbinary protoplanetary disc in a polar configuration
• Inclination Evolution of Protoplanetary Disks Around Eccentric Binaries
• The Formation and Evolution of Wide-Orbit Stellar Multiples In Magnetized Clouds
• Multiple Stellar Evolution: a population synthesis algorithm to model the stellar, binary, and dynamical evolution of multiple-star systems
• Multiplicity and clustering in Taurus star-forming region. I. Unexpected ultra-wide pairs of high-order multiplicity in Taurus
• The Araucaria Project: High-precision orbital parallax and masses of eclipsing binaries from infrared interferometry
• Spectroscopic orbits of subsystems in multiple stars. VI
• Long live the disk: lifetimes of protoplanetary disks in hierarchical triple star systems and a possible explanation for HD 98800 B
• HD 98800: A most unusual debris disc
• The GRAVITY young stellar object survey V. The orbit of the T Tauri binary star WW Cha

Cited by in corpus (7)

• A Census of the TW Hya Association with Gaia
• Speckle Interferometry at SOAR in 2021
• The eclipse of the V773 Tau B circumbinary disk
• Precession and polar alignment of accretion discs in triple (or multiple) stellar systems
• Grid-Based Simulations of Polar Circumbinary Disks: Polar Alignment and Vortex Formation
• On the frequencies of circumbinary discs in protostellar systems
• Accretion onto a binary from a polar circumbinary disc