Direct imaging of extra-solar planets in star forming regions

Mawet, Dimitri; Absil, Olivier; Montagnier, G.; Riaud, Pierre; Surdej, Jean; Ducourant, C.; Augereau, J.-C.; Rottinger, Sarah; Girard, J.; Krist, John; Stapelfeldt, K.

doi:10.1051/0004-6361/201219662

Cited by 41 publications

(33 citation statements)

References 49 publications

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“…4, right panel). This suggests that the ice composition is likely similar, despite the significant age difference: 0.5 -1 Myr for IMLupi (Mawet et al 2012) The C 18 O emission has a brightness temperature of ≈ 8 K on both surfaces between 150 and 300 au. With an excitation temperature of 21 K as for 13 CO, this means that the C 18 O optical depth is of the order of 0.5.…”

Section: Two-dimensional Temperature Structure and Vertical Co Snow Linementioning

confidence: 95%

Direct mapping of the temperature and velocity gradients in discs

Pinte

Ménard

Duchêne

et al. 2018

A&A

185

253

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Accurate measurements of the physical structure of protoplanetary discs are critical inputs for planet formation models. These constraints are traditionally established via complex modelling of continuum and line observations. Instead, we present an empirical framework to locate the CO isotopologue emitting surfaces from high spectral and spatial resolution ALMA observations. We apply this framework to the disc surrounding IM Lupi, where we report the first direct, i.e. model independent, measurements of the radial and vertical gradients of temperature and velocity in a protoplanetary disc. The measured disc structure is consistent with an irradiated self-similar disc structure, where the temperature increases and the velocity decreases towards the disc surface. We also directly map the vertical CO snow line, which is located at about one gas scale height at radii between 150 and 300 au, with a CO freeze-out temperature of 21 ± 2 K. In the outer disc (> 300 au), where the gas surface density transitions from a power law to an exponential taper, the velocity rotation field becomes significantly sub-Keplerian, in agreement with the expected steeper pressure gradient. The sub-Keplerian velocities should result in a very efficient inward migration of large dust grains, explaining the lack of millimetre continuum emission outside of 300 au. The sub-Keplerian motions may also be the signature of the base of an externally irradiated photo-evaporative wind. In the same outer region, the measured CO temperature above the snow line decreases to ≈ 15 K because of the reduced gas density, which can result in a lower CO freeze-out temperature, photo-desorption, or deviations from local thermodynamic equilibrium.

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Section: Two-dimensional Temperature Structure and Vertical Co Snow Linementioning

confidence: 95%

Direct mapping of the temperature and velocity gradients in discs

Pinte

Ménard

Duchêne

et al. 2018

A&A

185

253

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“…initiated space-and ground-based searches for a Jupiter-like planet around the star (Mawet et al 2012). …”

Section: Im Lup (Sz 82)mentioning

confidence: 99%

Stable and unstable accretion in the classical T Tauri stars IM Lup and RU Lup as observed byMOST

Siwak

Ogłoza

Ruciński

et al. 2016

Mon. Not. R. Astron. Soc.

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Results of the time variability monitoring of the two classical T Tauri stars, RU Lup and IM Lup, are presented. Three photometric data sets were utilised: (1) simultaneous (same field) MOST satellite observations over four weeks in each of the years 2012 and 2013, (2) multicolour observations at the SAAO in April -May of 2013, (3) archival Vfilter ASAS data for nine seasons, 2001 -2009. They were augmented by an analysis of high-resolution, public-domain VLT-UT2 UVES spectra from the years 2000 to 2012. From the MOST observations, we infer that irregular light variations of RU Lup are caused by stochastic variability of hot spots induced by unstable accretion. In contrast, the MOST light curves of IM Lup are fairly regular and modulated with a period of about 7.19 -7.58 d, which is in accord with ASAS observations showing a well defined 7.247 ± 0.026 d periodicity. We propose that this is the rotational period of IM Lup and is due to the changing visibility of two antipodal hot spots created near the stellar magnetic poles during the stable process of accretion. Re-analysis of RU Lup highresolution spectra with the Broadening Function approach reveals signs of a large polar cold spot, which is fairly stable over 13 years. As the star rotates, the spotinduced depression of intensity in the Broadening Function profiles changes cyclically with period 3.71058 d, which was previously found by the spectral cross-correlation method.

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“…IM Lup is a young (0.5−1 Myr; Mawet et al 2012) M0 type star associated with the Lupus 2 cloud, at a distance of d = 161 ± 10 pc (Gaia Collaboration et al 2016). The star has a bolometric luminosity of L * = 0.9 L (Hughes et al 1994) and mass of 1 M (Panić et al 2009).…”

Section: Introductionmentioning

confidence: 99%

THE COUPLED PHYSICAL STRUCTURE OF GAS AND DUST IN THE IM Lup PROTOPLANETARY DISK

Cleeves

Öberg

Wilner

et al. 2016

ApJ

181

233

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The spatial distribution of gas and solids in protoplanetary disks determines the composition and formation efficiency of planetary systems. A number of disks show starkly different distributions for the gas and small grains compared to millimeter-centimeter sized dust. We present new Atacama Large Millimeter/Submillimeter Array (ALMA) observations of the dust continuum, CO, 13 CO, and C 18 O in the IM Lup protoplanetary disk, one of the first systems where this dust-gas dichotomy was clearly seen. The 12 CO is detected out to a radius of 970 AU, while the millimeter continuum emission is truncated at just 313 AU. Based upon this data, we have built a comprehensive physical and chemical model for the disk structure, which takes into account the complex, coupled nature of the gas and dust and the interplay between the local and external environment. We constrain the distributions of gas and dust, the gas temperatures, the CO abundances, the CO optical depths, and the incident external radiation field. We find that the reduction/removal of dust from the outer disk exposes this region to higher stellar and external radiation and decreases the rate of freeze-out, allowing CO to remain in the gas out to large radial distances. We estimate a gas-phase CO abundance of 5% of the ISM value and a low external radiation field (G 0 4). The latter is consistent with that expected from the local stellar population. We additionally find tentative evidence for ring-like continuum substructure, suggestions of isotope-selective photodissociation, and a diffuse gas halo.

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Direct imaging of extra-solar planets in star forming regions

Cited by 41 publications

References 49 publications

Direct mapping of the temperature and velocity gradients in discs

Direct mapping of the temperature and velocity gradients in discs

Stable and unstable accretion in the classical T Tauri stars IM Lup and RU Lup as observed byMOST

THE COUPLED PHYSICAL STRUCTURE OF GAS AND DUST IN THE IM Lup PROTOPLANETARY DISK

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