TIMMI: a 10-μm camera for the ESO 3.6-m telescope

Lagage, Pierre-Olivier; Jouan, R.; Massé, Pierre; Mestreau, P.; Tarrius, A.; Kaeufl, H. U.

doi:10.1117/12.158720

Cited by 21 publications

(20 citation statements)

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“…For the thermal-IR part of our program, we used the VISIR instrument (Lagage et al 2004), installed at the Cassegrain focus of the Melipal telescope (UT3) of the ESO/Very Large Telescope Article published by EDP Sciences (Paranal, Chile). VISIR is a mid-IR imager, that also provides a slit spectrometer.…”

Section: Visirmentioning

confidence: 99%

The nearby eclipsing stellar systemδVelorum

Kervella¹,

Thévenin

Petr-Gotzens

2008

A&A

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Context. The triple stellar system δ Vel system presents a significant infrared excess, whose origin is still being debated. A large infrared bow shock has been discovered using Spitzer/MIPS observations. Although it appears as a significant contributor to the measured IR excess, the possibility exists that a circumstellar IR excess is present around the stars of the system. Aims. The objective of the present VISIR and NACO observations is to identify whether one of the stars of the δ Vel system presents a circumstellar photometric excess in the thermal IR domain and to quantify it. Methods. We observed δ Vel using the imaging modes of the ESO/VLT instruments VISIR (in BURST mode) and NACO to resolve the A-B system (0.6 separation) and obtain the photometry of each star. We also obtained one NACO photometry epoch precisely at the primary (annular) eclipse of δ Vel Aa by Ab. Results. Our photometric measurements with NACO (2.17 μm), complemented by the existing visible photometry allowed us to reconstruct the spectral energy distribution of the three stars. We then compared the VISIR photometry (8.6-12.8 μm) to the expected photospheric emission from the three stars at the corresponding wavelengths. Conclusions. We can exclude the presence of a circumstellar thermal infrared excess around δ Vel A or B down to a few percent level. This supports the conclusions of Gáspár et al. (2008, ApJ, 672, 974) that the IR excess of δ Vel has an interstellar origin, although a cold circumstellar disk could still be present. In addition, we derive the spectral types of the three stars Aa, Ab, and B (respectively A2IV, A4V and F8V), and we estimate the age of the system around 400-500 Myr.

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Section: Visirmentioning

confidence: 99%

The nearby eclipsing stellar systemδVelorum

Kervella¹,

Thévenin

Petr-Gotzens

2008

A&A

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“…Observations were performed in 1995, February 05 and 07 at the ESO 3.6-m telescope in La Silla (Chile), using the midinfrared TIMMI camera (Lagage et al 1993) with a detector consisting of a 64 × 64 pixel Ga:Si array. The resulting spatial scale of the system is 0.336 /pix.…”

Section: Timmi Imagingmentioning

confidence: 99%

New insights on the complex planetary nebula Hen 2-113

Lagadec¹,

Chesneau

Matsuura

et al. 2006

A&A

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We report on infrared observations of the planetary nebula Hen 2-113 obtained with VLT/NACO, VLTI/MIDI, VLT/ISAAC and TIMMI at the ESO 3.6 m. Hen 2-113 exhibits a clear ring-like structure superimposed to a more diffuse environment visible in the L (3.8 µm), M (4.78 µm) and 8.7 µm bands. No clear core at 8.7 µm and no fringes through the N band could be detected for this object with MIDI. A qualitative interpretation of the object structure is proposed using a diabolo-like geometrical model. The PAH content of the nebula was also studied with ISAAC and TIMMI observations. This indicates that the PAHs are mostly concentrated towards the lobes of the diabolo and the bipolar lobes of the nebula. In L band, a void 0.3 in diameter was discovered with NACO around the central source. The L and M fluxes from the central source were derived from NACO data indicating an important infrared excess with respect to the expected stellar emission based on stellar models and short wavelength data. The observed flux from this source in the L and M is about 300 and 800 times respectively than those expected from a model including only the central star. Moreover, the central object appears resolved in L band with measured FWHM of 155 mas. This infrared excess can be explained by emission from a cocoon of hot dust (T ∼ 1000 K) with a total mass ∼10 −9 M .

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“…We used the VISIR instrument (Lagage et al 2004), installed at the Cassegrain focus of the Melipal telescope (UT3) of the VLT (Paranal, Chile). VISIR is a mid-IR imager that also provides a slit spectrometer.…”

Section: Visir Observationsmentioning

confidence: 99%

The circumstellar envelopes of the Cepheids $\mathsf{\ell}$ Carinae and RS Puppis

Kervella¹,

Mérand

Gallenne

2009

A&A

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Context. Compact circumstellar envelopes (CSEs) have been detected around several Cepheids by interferometry. In particular, observations with the VINCI instrument revealed in 2006 a compact envelope around the long period Cepheid Car (P = 35.5 days). Another Cepheid, RS Pup (P = 41.4 days), presents a large (≈2 ) circumstellar nebula scattering the Cepheid light in the visible. These envelopes are particularly interesting for two reasons: their presence could impact the Cepheid distance scale, and they could imply stellar mass loss. Aims. Our goal is to establish the spatial and spectral properties of the CSEs of Car and RS Pup. This is done through a parametrization of the envelopes in terms of fractional flux (with respect to the star) and angular size. Methods. We retrieved archival Spitzer images of the two stars (λ = 3.5−70 μm), and obtained new diffraction-limited imaging with the VLT/VISIR camera in BURST mode (λ = 8.6−11.9 μm), as well as interferometric observations with the VLTI/MIDI beam combiner (λ = 8−13 μm). This combination of single-telescope and interferometric techniques allows us to probe the envelopes of the two Cepheids over a broad range of angular scales, from arcminutes to milliarcseconds. Results. The circumstellar envelope of RS Pup is resolved spatially at 24 and 70 μm by Spitzer, and around 10 μm by MIDI and VISIR. The envelope of Car appears much more compact, and is resolved only in the VISIR and MIDI observations. The infrared excesses we detect around RS Pup and Car are both very significant, but differ considerably in spectral and spatial properties. We detect a warm component in the CSE of both stars at a spatial scale of a few 100 to a few 1000 AU. In addition, RS Pup presents a very large (several 100 000 AU) and cold (≈40 K) dusty envelope. Conclusions. The observed properties of the CSEs lead us to propose that the cold dust content of the large reflection nebula surrounding RS Pup has an interstellar origin, while the warm CSEs of the two stars were created by ongoing stellar mass loss. We also speculate that the NGC 7023 reflection nebula surrounding the Herbig Be star HD 200775 is an analogue of RS Pup at an age of 100 000 years. The presence of CSEs around the two brightest long-period Cepheids is an indication that many long-period members of this class, if not all, could be surrounded by warm circumstellar envelopes created by mass loss. However, very large dusty envelopes such as that of RS Pup are probably less common, as according to our scenario, they require the presence of a high dust density in the interstellar medium (ISM) at the time of the formation of the Cepheid progenitor.

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TIMMI: a 10-μm camera for the ESO 3.6-m telescope

Cited by 21 publications

References 0 publications

The nearby eclipsing stellar systemδVelorum

The nearby eclipsing stellar systemδVelorum

New insights on the complex planetary nebula Hen 2-113

The circumstellar envelopes of the Cepheids $\mathsf{\ell}$ Carinae and RS Puppis

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