A Young Planet Search in Visible and IR Light: DN Tau, V836 Tau, and V827 Tau

Abstract

In searches for low-mass companions to late-type stars, correlation between radial velocity variations and line bisector slope changes indicates contamination by large starspots. Two young stars demonstrate that this test is not sufficient to rule out starspots as a cause of radial velocity variations. As part of our survey for substellar companions to T Tauri stars, we identified the ~2 Myr old planet host candidates DN Tau and V836 Tau. In both cases, visible light radial velocity modulation appears periodic and is uncorrelated with line bisector span variations, suggesting close companions of several M_Jup in these systems. However, high-resolution, infrared spectroscopy shows that starspots cause the radial velocity variations. We also report unambiguous results for V827 Tau, identified as a spotted star on the basis of both visible light and infrared spectroscopy. Our results suggest that infrared follow up observations are critical for determining the source of radial velocity modulation in young, spotted stars.

Accepted for publication in the Astrophysical Journal Letters

References in corpus (7)

• The Magnetic Fields of Classical T Tauri Stars
• Search for exoplanets with the radial-velocity technique: quantitative diagnostics of stellar activity
• Results of the ROTOR-program. II. The long-term photometric variability of weak-line T Tauri stars
• Retired A Stars and Their Companions II: Jovian planets orbiting kappa Coronae Borealis and HD167042
• Multiepoch Radial Velocity Observations of L Dwarfs
• A Spectroscopic Binary at the M/L Transition
• Star Spot Induced Radial Velocity Variability in LkCa 19