Spatial Study with the Very Large Telescope of a New Resolved Edge‐on Circumstellar Dust Disk Discovered at the Periphery of the ρ Ophiuchi Dark Cloud

Abstract

We report the discovery in near-infrared (NIR) with SofI at the New Technology Telescope (NTT) of a resolved circumstellar dust disk around a 2MASS source at the periphery of the Ophiuchi dark cloud. We present follow-up observations in J, H, and K s bands, obtained with ISAAC at the Very Large Telescope (VLT) under 0>4 seeing conditions, which unveil a dark dust lane oriented east-west between two characteristic northern and southern reflection nebulae. This new circumstellar dust disk has a radius of 2>15 (300 AU at 140 pc) and a width of 1>2 (170 AU at 140 pc). Thanks to its location at the periphery of the dense cores, it suffers small foreground visual extinction (A V ¼ 2:1 AE 2:6 mag). Although this disk is seen close to edge-on, the two reflection nebulae display very different colors. We introduce a new NIR data visualization called '' pixel NIR color mapping '' (PICMap for short), which allows us to visualize directly the NIR colors of the nebula pixels. Thanks to this method, we identify a ridge, 0>3 (40 AU at 140 pc) to the north of the dark lane and parallel to it, that displays an NIR color excess. This ridge corresponds to an unusual increase of brightness from J to K s , which is also visible in the NTT observations obtained 130 days before the VLT ones. We also find that the northern nebula shows $3 mag more extinction than the southern nebula. We compute axisymmetric disk models to reproduce the VLT scattered-light images and the spectral energy distribution from optical to NIR. Our best model, with a disk inclination i ¼ 86 AE 1 , correctly reproduces the extension of the southern reflection nebula, but it is not able to reproduce either the observed NIR color excess in the northern nebula or the extinction difference between the two reflection nebulae. We discuss the possible origin of the peculiar, asymmetrical NIR color properties of this object.

New low-mass members of the Lupus 3 dark cloud: Further indications of pre-main-sequence evolution strongly affected by accretion

“…Many other young stellar objects surrounded by edge-on disks are currently known (e.g. Burrows et al 1996;McCaughrean & O'Dell 1996, Stapelfeldt et al 1998Woitas & Leinert 1998, Monin & Bouvier 2000Brandner et al 2000;Jayawardhana et al 2002;Grosso et al 2003) or suspected (Martín 2000).…”

AKARI observations of ice absorption bands towards edge-on young stellar objects

“…(e) Hodapp et al (2004). ( f ) Grosso et al (2003). (g) Inclination of HV Tau C (Monin & Bouvier 2000).…”

Dynamical Masses of Low-mass Stars in the Taurus and Ophiuchus Star-forming Regions

“…All are in L1688. Except for the Flying Saucer (2MASS J16281370-2431391 Grosso et al 2003), the stellar parameters are from Ricci et al (2010a, R10a) and Najita et al (2015). We converted the SpTy's to T eff s using the look-up table from Pecaut & Mamajek (2013), applied an uncertainty of ±1 sub-type.…”

“…McClure et al (2010) identify all the stars as Class II PMS stars except for GSS 26 and GY 284 listed as flat spectrum sources (FS) and YLW16C (= GY 262) for which a designation is not available Najita et al (2015), McClure et al (2010) Stars in L1688 from the SED slope between 2 and 25 µm (but for which an envelope is excluded from the SED slope between 5 and 12 µm). The Flying Saucer is an edge-on disk dominated by scattered light; its parameters are from Grosso et al (2003) and Pontoppidan et al (2007). Both groups assumed a Kurucz (1979) stellar atmosphere model at T eff = 3500K to derive the luminosity of the central star from SED modeling.…”

“…Both groups assumed a Kurucz (1979) stellar atmosphere model at T eff = 3500K to derive the luminosity of the central star from SED modeling. From an extinction map around the Flying Saucer, Grosso et al (2003) derived A v =2.1 mag and L * /L =0.14 at a distance of 140 pc corresponding to L * /L =0.10 at 119 pc. Pontoppidan et al (2007) assumed A v =0.50 mag, added an accretion luminosity L acc /L = 0.6 and L * /L =0.084 at 125 pc which scales to L * /L = 0.076 at 119 pc.…”