Deep near-IR variability survey of pre-main-sequence stars in Rho Ophiuchi

Abstract

Variability is a common characteristic of pre-main-sequence stars (PMS). Near-IR variability surveys of young stellar objects (YSOs) can probe stellar and circumstellar environments and provide information about the dynamics of the on going magnetic and accretion processes. Furthermore, variability can be used as a tool to uncover new cluster members in star formation regions. We hope to achieve the deepest near-IR variability study of YSOs targeting the Rho Ophiuchi cluster. Fourteen epochs of observations were obtained with the Wide Field Camera (WFCAM) at the UKIRT telescope scheduled in a manner that allowed the study of variability on timescales of days, months, and years. Statistical tools, such as the multi-band cross correlation index and the reduced chi-square, were used to disentangle signals of variability from noise. Variability characteristics are compared to existing models of YSOs in order to relate them to physical processes, and then used to select new candidate members of this star-forming region. Variability in the near-IR is found to be present in 41% of the known population of Rho Ophiuchi recovered in our sample. The behaviours shown are several and can be associated with the existence of spots on the stellar surface, variations in circumstellar extinction, or changes in the geometry of an accretion disc. Using variability, a new population of objects has been uncovered that is believed to be part of the Rho Ophiuchi cluster.

Accepted for publication in A&A

References in corpus (8)

• The UKIRT Infrared Deep Sky Survey (UKIDSS)
• Accretion in the Rho-Oph pre-main sequence stars
• The UKIRT Infrared Deep Sky Survey Early Data Release
• Results of the ROTOR-program. I. The long-term photometric variability of classical T Tauri stars
• Hipparcos distances of Ophiuchus and Lupus cloud complexes
• Results of the ROTOR-program. II. The long-term photometric variability of weak-line T Tauri stars
• Spitzer IRS spectra of a large sample of Seyfert galaxies: a variety of infrared SEDs in the local AGN population
• A Survey for New Members of Taurus with the Spitzer Space Telescope

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• POISSON project - III - Investigating the evolution of the mass accretion rate
• YSOVAR: Mid-IR variability in the star forming region Lynds 1688
• The Peculiar Periodic YSO WL 4 in Rho Ophiuchus
• Long-term variability of T Tauri stars using WASP
• Near-IR Spectroscopic Monitoring of Class I Protostars: Variability of Accretion and Wind Indicators
• Proper motion survey and kinematic analysis of the Rho Ophiuchi embedded cluster
• Where are the magnetar binary companions? Candidates from a comparison with binary population synthesis predictions
• New candidates for magnetar counterparts from a deep search with the Hubble Space Telescope
• Near-Infrared Variability of Low Mass Stars in IC 1396A and TR 37
• Keck Observations in the INfrared of Taurus and $\rho$ Oph Exoplanets And Ultracool dwarfs (KOINTREAU) II: Two Young Bound Companions to Ophiuchus Stars