First result with AMBER+FINITO on the VLTI: 
 the high-precision angular diameter of V3879 Sagittarii

Bouquin, J.-B. Le; Bauvir, Bertrand; Haguenauer, Pierre; Schöller, M.; Rantakyrö, Fredrik T.; Ménardi, Serge

doi:10.1051/0004-6361:20078550

Cited by 30 publications

(25 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Their stellar parameters, including their diameters, can be found in Table 2. About 25% of the observations were performed using the VLTI fringe-tracker FINITO that uses 70% of the H band flux to measure the relative optical path difference between the light beams (Le Bouquin et al 2008). …”

Section: Observations At Vltimentioning

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

View full text Add to dashboard Cite

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.

show abstract

Section: Observations At Vltimentioning

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

View full text Add to dashboard Cite

show abstract

“…Each measurement for HR 5999 was encircled by observations of a calibrator targets (HD 136014, HD 123004, HD 145921, HD 137730) to measure the instrumental transfer function and correct for instrumental effects. About 20% of the observations were performed using the fringe-tracker FINITO (Le Bouquin et al 2008).…”

Section: Amber Measurementsmentioning

confidence: 99%

A low optical depth region in the inner disk of the Herbig Ae star HR 5999

Benisty

Renard

Natta

et al. 2011

A&A

View full text Add to dashboard Cite

Context. Circumstellar disks surrounding young stars are known to be the birthplaces of planetary systems, and the innermost astronomical unit is of particular interest. Near-infrared interferometric studies have revealed a complex morphology for the close environment surrounding Herbig Ae stars. Aims. We present new long-baseline spectro-interferometric observations of the Herbig Ae star, HR 5999, obtained in the H and K bands with the AMBER instrument at the VLTI, and aim to produce near-infrared images at the sub-AU spatial scale. Methods. We spatially resolve the circumstellar material and reconstruct images in the H and K bands using the MiRA algorithm. In addition, we interpret the interferometric observations using models that assume that the near-infrared excess is dominated by the emission of a circumstellar disk. We compare the images reconstructed from the VLTI measurements to images obtained using simulated model data.Results. The K-band image reveals three main elements: a ring-like feature located at ∼0.65 AU, a low surface brightness region inside 0.65 AU, and a central spot. At the maximum angular resolution of our observations (B/λ ∼ 1.3 mas), the ring is resolved while the central spot is only marginally resolved, preventing us from revealing the exact morphology of the circumstellar environment. We suggest that the ring traces silicate condensation, i.e., an opacity change, in a circumstellar disk around HR 5999. We build a model that includes a ring at the silicate sublimation radius and an inner disk of low surface brightness responsible for a large amount of the near-infrared continuum emission. The model successfully fits the SED, visibilities, and closure phases in the H and K bands, and provides evidence of a low surface brightness region inside the silicate sublimation radius. Conclusions. This study provides milli-arcsecond resolution images of the environment of HR 5999 and additional evidence that in Herbig Ae stars, there is material in a low surface brightness region, probably a low optical depth region, located inside the silicate sublimation radius and of unknown nature. The possibility that the formation of such a region in a thick disk is related to disk evolution should be investigated.

show abstract

“…This effect still remains weak and is beyond the performances of current interferometers as soon as the flux ratio is less than about 1%. However, besides the fact the companion is not detectable, studies around visibility nulls keep their interest for precise diameter and limb darkening measurements (Le Bouquin et al 2008). …”

Section: Visibility Of a Resolved Star With A Faint Companionmentioning

confidence: 99%

Phase closure nulling

Chelli¹,

Duvert²,

Malbet³

et al. 2009

A&A

View full text Add to dashboard Cite

We provide a complete theory of the phase closure of a binary system in which a small, feeble, and unresolved companion acts as a perturbing parameter on the spatial frequency spectrum of a dominant, bright, resolved source. We demonstrate that the influence of the companion can be measured with precision by measuring the phase closure of the system near the nulls of the primary visibility function. In these regions of phase closure nulling, frequency intervals always exist where the phase closure signature of the companion is larger than any systematic error and can then be measured. We show that this technique allows retrieval of many astrophysically relevant properties of faint and close companions such as flux, position, and in favorable cases, spectrum. We conclude by a rapid study of the potentialities of phase closure nulling observations with current interferometers and explore the requirements for a new type of dedicated instrument.

show abstract

First result with AMBER+FINITO on the VLTI: the high-precision angular diameter of V3879 Sagittarii

Cited by 30 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?

A low optical depth region in the inner disk of the Herbig Ae star HR 5999

Phase closure nulling

Contact Info

Product

Resources

About