Patrick Abraham

Discovery of Molecular Gas around HD 131835 in an APEX Molecular Line Survey of Bright Debris Disks

Debris disks are considered to be gas-poor, but recent observations revealed molecular or atomic gas in several 10-40 Myr old systems. We used the APEX and IRAM 30m radiotelescopes to search for CO gas in 20 bright debris disks. In one case, around the 16 Myr old A-type star HD 131835, we discovered a new gas-bearing debris disk, where the CO 3-2 transition was successfully detected. No other individual system exhibited a measurable CO signal. Our Herschel Space Observatory far-infrared images of HD 131835 marginally resolved the disk both at 70 and 100

MATISSE: perspective of imaging in the mid-infrared at the VLTI

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Sky confusion noise in the far-infrared: Cirrus, galaxies and the cosmic far{infrared background ?

m, with a characteristic radius of ~170 au. While in stellar properties HD 131835 resembles

Fundamental vibrational transition of CO during the outburst of EX Lupi in 2008

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Mid-infrared spectrum of the zodiacal light observed with ISOPHOT

Pic, its dust disk properties are similar to those of the most massive young debris disks. With the detection of gas in HD 131835 the number of known debris disks with CO content has increased to four, all of them encircling young (

Small-scale structure of the galactic cirrus emission

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Detection of solid ammonia, methanol, and methane with ISOPHOT

40 Myr) A-type stars. Based on statistics within 125 pc, we suggest that the presence of detectable amount of gas in the most massive debris disks around young A-type stars is a common phenomenon. Our current data cannot conclude on the origin of gas in HD 131835. If the gas is secondary, arising from the disruption of planetesimals, then HD 131835 is a comparably young and in terms of its disk more massive analogue of the

MATISSE a four beams combiner in the mid-infrared for the VLTI

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VLTI/MIDI atlas of disks around low- and intermediate-mass young stellar objects

Pic system. However, it is also possible that this system similarly to HD 21997 possesses a hybrid disk, where the gas material is predominantly primordial, while the dust grains are mostly derived from planetesimals.

Zodiacal light observations with the infrared space observatory

MATISSE is foreseen as a mid-infrared spectro-interferometer combining the beams of up to four UTs/ATs of the Very Large Telescope Interferometer (VLTI) of the European Southern Observatory. The related science case study demonstrates the enormous capability of a new generation mid-infrared beam combiner. MATISSE will constitute an evolution of the two-beam interferometric instrument MIDI. MIDI is a very successful instrument which offers a perfect combination of spectral and angular resolution. New characteristics present in MATISSE will give access to the mapping and the distribution of the material (typically dust) in the circumstellar environments by using a wide mid-infrared band coverage extended to L, M and N spectral bands. The four beam combination of MATISSE provides an efficient UV-coverage : 6 visibility points are measured in one set and 4 closure phase relations which can provide aperture synthesis images in the mid-infrared spectral regime.