A Data Exchange Standard for Optical (Visible/IR) Interferometry

We present new long-baseline spectro-interferometric observations of the Herbig Ae star HD 163296 (MWC 275) obtained in the H and K bands with the AMBER instrument at the VLTI. The observations cover a range of spatial resolutions between ∼3 and ∼12 milliarcseconds, with a spectral resolution of ∼30. With a total of 1481 visibilities and 432 closure phases, they represent the most comprehensive (u, v) coverage achieved so far for a young star. The circumstellar material is resolved at the sub-AU spatial scale and closure phase measurements indicate a small but significant deviation from point-symmetry. We discuss the results assuming that the near-infrared excess in HD 163296 is dominated by the emission of a circumstellar disk. A successful fit to the spectral energy distribution, near-infrared visibilities and closure phases is found with a model in which a dominant contribution to the H and K band emission originates in an optically thin, smooth and point-symmetric region extending from about 0.1 to 0.45 AU. At a distance of 0.45 AU from the star, silicates condense, the disk becomes optically thick and develops a puffed-up rim, whose skewed emission can account for the non-zero closure phases. We discuss the source of the inner disk emission and tentatively exclude dense molecular gas as well as optically thin atomic or ionized gas as its possible origin. We propose instead that the smooth inner emission is produced by very refractory grains in a partially cleared region, extending to at least ∼0.5 AU. If so, we may be observing the disk of HD 163296 just before it reaches the transition disk phase. However, we note that the nature of the refractory grains or, in fact, even the possibility of any grain surviving at the very high temperatures we require (∼2100−2300 K at 0.1 AU from the star) is unclear and should be investigated further.

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“…The processed data will be made available for the community in the OI-FITS format (Pauls et al 2005) on the OLBIN website 1 in January 2010.…”

Section: Data Reductionmentioning

confidence: 99%

Strong near-infrared emission in the sub-AU disk of the Herbig Ae star HD 163296: evidence of refractory dust?

Benisty

Natta²,

Isella

et al. 2010

A&A

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“…Our calibrated data set resulted in the following statistically independent measurements: 27 V 2 and 9 CP in 2003, 111 V 2 and 37 CP in 2004 and 6 V 2 and 3 CP measurements in 2005. The calibrated data are available from the authors in the OI-FITS format (Pauls et al 2005). …”

Section: Observations and Data Reductionmentioning

confidence: 99%

First astronomical unit scale image of the GW Orionis triple system

Berger

Monnier

Millan-Gabet

et al. 2011

A&A

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Context. Young and close multiple systems are unique laboratories to probe the initial dynamical interactions between forming stellar systems and their dust and gas environment. Their study is a key building block to understanding the high frequency of main-sequence multiple systems. However, the number of detected spectroscopic young multiple systems that allow dynamical studies is limited. GW Orionis is one such system. It is one of the brightest young T Tauri stars and is surrounded by a massive disk. Aims. Our goal is to probe the GW Orionis multiplicity at angular scales at which we can spatially resolve the orbit. Methods. We used the IOTA/IONIC3 interferometer to probe the environment of GW Orionis with an astronomical unit resolution in 2003, 2004, and 2005. By measuring squared visibilities and closure phases with a good UV coverage we carry out the first image reconstruction of GW Ori from infrared long-baseline interferometry. Results. We obtained the first infrared image of a T Tauri multiple system with astronomical unit resolution.We show that GW Orionis is a triple system, resolve for the first time the previously known inner pair (separation ρ ∼ 1.4 AU) and reveal a new more distant component (GW Ori C) with a projected separation of ∼8 AU with direct evidence of motion. Furthermore, the nearly equal (2:1) H-band flux ratio of the inner components suggests that either GW Ori B is undergoing a preferential accretion event that increases its disk luminosity or that the estimate of the masses has to be revisited in favour of a more equal mass-ratio system that is seen at lower inclination. Conclusions. Accretion disk models of GW Ori will need to be completely reconsidered because of this outer companion C and the unexpected brightness of companion B.

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“…The UV-averaged visibility data for each epoch are presented in Figure 1, along with some Gaussian profiles for comparison. The IOTA closure phase results are shown in Figure 2, products are stored in the FITS-based, optical interferometry data exchange format (OI-FITS), recently described in Pauls et al (2005).…”

Section: Observationsmentioning

confidence: 99%

No Expanding Fireball: Resolving the Recurrent Nova RS Ophiuchi with Infrared Interferometry

Monnier

Barry

Traub

et al. 2006

ApJ

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Following the recent outburst of the recurrent nova RS Oph on 2006 February 12, we measured its near-infrared size using the IOTA, Keck, and PTI Interferometers at multiple epochs. The characteristic size of ∼3 mas hardly changed over the first 60 days of the outburst, ruling out currently popular models whereby the near-infrared emission arises from hot gas in the expanding shock. The emission was also found to be significantly asymmetric, evidenced by nonzero closure phases detected by IOTA. The physical interpretation of these data depends strongly on the adopted distance to RS Oph. Our data can be interpreted as the first direct detection of the underlying RS Oph binary, lending support to the recent "reborn red giant" models of Hachisu & Kato. However, this result hinges on an RS Oph distance of Շ540 pc, in strong disagreement with the widely adopted distance of ∼1.6 kpc. At the farther distance, our observations imply instead the existence of a nonexpanding, dense, and ionized circumbinary gaseous disk or reservoir responsible for the bulk of the near-infrared emission. Longer baseline infrared interferometry is uniquely suited to distinguish between these models and to ultimately determine the distance, binary orbit, and component masses for RS Oph, one of the closest known (candidate) Type 1a supernova progenitor systems.

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A Data Exchange Standard for Optical (Visible/IR) Interferometry

Cited by 122 publications

References 5 publications

Strong near-infrared emission in the sub-AU disk of the Herbig Ae star HD 163296: evidence of refractory dust?

Strong near-infrared emission in the sub-AU disk of the Herbig Ae star HD 163296: evidence of refractory dust?

First astronomical unit scale image of the GW Orionis triple system

No Expanding Fireball: Resolving the Recurrent Nova RS Ophiuchi with Infrared Interferometry

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