Dippers from TESS Full-frame Images. II. Spectroscopic Characterization of Four Young Dippers

Abstract

Photometric monitoring by the Transiting Exoplanet Survey Satellite (TESS) has discovered not only periodic signals by transiting exoplanets but also episodic or quasi-periodic dimming around young stellar objects. The mechanisms of the dimming of these objects, so-called "dippers", are thought to be related to the property of the accretion or the structure of protoplanetary disks especially in regions close to the host star. Recently, we have created the catalog of dippers from the one year of TESS Full Frame Image (FFI) data. In this paper, we report spectral features of four newly found dippers in that catalog and show that they potentially shed light on the dimming mechanisms. We found that all of the targets exhibit the H alpha emission line, which is an indicator of an ongoing accretion. Based on its line profiles and/or their variability, we characterized the properties of the disks of each source, which can support the dimming mechanisms due to a dusty disk wind or an accretion warp. Also, we found an interesting dipper (TIC 317873721), "close-in binary dipper," showing the complex variability of the line profile and the large radial velocity variation. Since the dimming intervals are similar to the orbital period of the binary, we suggest that the dips are caused by dust in the warp of accretion from a circumbinary disk onto stars. Such a close-in ($<$ 0.1 au) binary dipper is rarely reported so far, further investigation will reveal the new aspect of the disk evolution and planetary formation.

15 pages, 10 figures, accepted for publication in ApJS

References in corpus (19)

• Array Programming with NumPy
• astroquery: An Astronomical Web-Querying Package in Python
• VOSA: Virtual Observatory SED Analyzer. An application to the Collinder 69 open cluster
• Composable Effects for Flexible and Accelerated Probabilistic Programming in NumPyro
• CERES: A Set of Automated Routines for Echelle Spectra
• On the formation of H-alpha line emission around classical T Tauri stars
• A new library of theoretical stellar spectra with scaled-solar and alpha-enhanced mixtures
• Python Leap Second Management and Implementation of Precise Barycentric Correction (barycorrpy)
• CSI 2264: Probing the inner disks of AA Tau-like systems in NGC 2264
• Variability Properties of 4 Million Sources in the $TESS$ Input Catalog Observed with the Kilodegree Extremely Little Telescope Survey
• Periodic accretion from a circumbinary disk in the young binary UZ Tau E
• Disk Dispersal and Planet Formation Time Scales
• Large dust grains in the inner region of circumstellar disks
• On the mass accretion rate and infrared excess in Herbig Ae/Be Stars
• Calibration of the AKARI Far-infrared All Sky Survey Maps
• Triggered Star Formation on the Border of the Orion-Eridanus Superbubble
• Anomalous Accretion Activity and the Spotted Nature of the DQ Tau Binary System
• Planetesimals Around Stars with TESS (PAST): I. Transient Dimming of a Binary Solar Analog at the End of the Planet Accretion Era
• Tidal Effects on the Radial Velocities of V723 Mon: Additional Evidence for a Dark $3M_{\odot }$ Companion