scholarly journals ALMA and the Future of Millimeter Imaging Observations

2015 ◽  
Vol 10 (S314) ◽  
pp. 270-275
Author(s):  
David J. Wilner
Keyword(s):  
Angular Resolution ◽  
Planetary Systems ◽  
Circumstellar Disks ◽  
Direct Access ◽  
High Angular Resolution ◽  
Dynamical Structure ◽  
Millimeter Wavelengths ◽  
The Future ◽  
Critical Age ◽  
Moving Groups

AbstractThe Nearby Young Moving Groups sample the critical age when primordial disks around stars complete their transformation into planetary systems with associated debris. Millimeter wavelengths provide direct access to cool material in these circumstellar disks. The high angular resolution of interferometry at these long wavelengths enables resolved observations of solids in an optically thin regime, as well as the thermal, chemical, and dynamical structure of gas, if present. In this contribution, I briefly review the evolving landscape of millimeter telescopes, with emphasis on the revolutionary capabilities of the new international Atacama Large Millimeter/submillimeter Array (ALMA) and describe pertinent early science results.

scholarly journals Radio Interferometry Observations of the Hallmarks of Planet Formation

2013 ◽  
Vol 8 (S299) ◽  
pp. 80-89
Author(s):  
Sean M. Andrews
Keyword(s):  
Planet Formation ◽  
Angular Resolution ◽  
Planetary System ◽  
Planetary Systems ◽  
Protoplanetary Disks ◽  
Circumstellar Disks ◽  
High Angular Resolution ◽  
Radio Interferometry ◽  
New Directions ◽  
And Migration

AbstractSome of the fundamental processes involved in the evolution of circumstellar disks and the assembly of planetary systems are just now becoming accessible to astronomical observations. The new promise of observational work in the field of planet formation makes for a very dynamic research scenario, which is certain to be amplified in the coming years as the revolutionary Atacama Large Millimeter/submillimeter Array (ALMA) facility ramps up to full operations. To highlight the new directions being explored in these fields, this brief review will describe how high angular resolution measurements at millimeter/radio wavelengths are being used to study several crucial aspects of the formation and early evolution of planetary systems, including: the gas and dust structures of protoplanetary disks, the growth and migration of disk solids, and the interactions between a young planetary system and its natal, gas-rich disk.

scholarly journals Lunar Occultations of the SiO Masers in RLeo

1994 ◽  
Vol 140 ◽  
pp. 154-155
Author(s):  
J. Cernicharo ◽  
W. Brunswig ◽  
G. Paubert ◽  
S. Liechti
Keyword(s):  
Radio Telescope ◽  
Angular Resolution ◽  
High Angular Resolution ◽  
Linear Antenna ◽  
The Moon ◽  
Moderate Size ◽  
Millimeter Wavelengths ◽  
Vlbi Observations ◽  
The Ideal

VLBI observations show that the SiO maser emitting regions in oxygen-rich stars are very clumpy and that these clumps extend over a few stellar radii (Mclntosh et al. 1987; Colomer et al. 1992). These observations indicate that the ideal instrument for the study of the SiO masers is an interferometer with baselines covering between a few and several hundreds/thousands km. Such an instrument is so far unavailable.A classical way to get high angular resolution and a full beam synthesis with a single telescope of moderate size is through lunar occultations. This observing technique provides the angular resolution of a single linear antenna several kilometers long. However, at millimeter wavelengths the Fresnel fringes produced by the Moon limb as the source under study is occulted have never been observed. We present here the observation with the 30-m IRAM radio telescope of the v=1 J=2-1 line of SiO during an occultation (and reappearance) of R Leo by the Moon.

The future of high angular resolution x-ray astronomy

2008 ◽  
Author(s):  
Paul Gorenstein ◽  
Webster Cash ◽  
Neil Gehrels ◽  
Keith Gendreau ◽  
John Krizmanic ◽  
...  
Keyword(s):  
Angular Resolution ◽  
High Angular Resolution ◽  
X Ray ◽  
The Future

scholarly journals The Future of High Angular Resolution Star and Planet Formation Science in the Optical/Infrared

2004 ◽  
Vol 221 ◽  
pp. 471-479
Author(s):  
Lynne A. Hillenbrand
Keyword(s):  
Planet Formation ◽  
Angular Resolution ◽  
Time Frame ◽  
High Angular Resolution ◽  
The Future

This presentation summarizes how some of the most pressing questions in the field of star and planet formation can be addressed by high angular resolution optical/infrared capabilities, and how many of these capabilities will in fact be available with realization of the space and ground facilities currently being planned for the 2005-2020 time frame.

scholarly journals High Angular Resolution Observations of Protostellar Disks

1994 ◽  
Vol 158 ◽  
pp. 387-390
Author(s):  
J.-L. Monin ◽  
J. Bouvier ◽  
F. Malbet
Keyword(s):  
Near Infrared ◽  
Angular Resolution ◽  
Circumstellar Disks ◽  
Physical Structure ◽  
Young Stellar Objects ◽  
High Angular Resolution ◽  
Stellar Objects ◽  
Star Forming ◽  
T Tauri ◽  
Chromatic Properties

The existence of circumstellar disks around young stellar objects like T Tauri stars is now well accepted. Such disks would have solar system sizes and, at the distance of the nearest star forming cloud, an angular diameter of 0.01 to 1 arcsecond at most, requiring very high angular resolution to be detected. Due to the nature of the emission process in circumstellar disks and to chromatic properties of ground based observations, disk imaging is expected to be more efficient in the near infrared. Also, multi-aperture interferometry in this wavelength range (1 – 10 μm) is expected to bring considerable insight into the disks properties and evolution in revealing their inner physical structure.In this paper, we present synthetic images of circumstellar accretion disks. The images have been computed from a complete disk vertical structure model.

scholarly journals Chemistry of a newly detected circumbinary disk in Ophiuchus

2018 ◽  
Vol 614 ◽  
pp. A26 ◽  
Author(s):  
Elizabeth Artur de la Villarmois ◽  
Lars E. Kristensen ◽  
Jes K. Jørgensen ◽  
Edwin A. Bergin ◽  
Christian Brinch ◽  
...  
Keyword(s):  
Binary Systems ◽  
Angular Resolution ◽  
Circumstellar Disks ◽  
Carbon Chain ◽  
Physical Structure ◽  
Continuum Emission ◽  
High Angular Resolution ◽  
Density Region ◽  
Spatially Resolved ◽  
Molecular Abundances

Context. Astronomers recently started discovering exoplanets around binary systems. Therefore, understanding the formation and evolution of circumbinary disks and their environment is crucial for a complete scenario of planet formation. Aims. The purpose of this paper is to present the detection of a circumbinary disk around the system Oph-IRS67 and analyse its chemical and physical structure. Methods. We present high-angular-resolution (0.′′4, ~60 AU) observations of C17O, H13CO+, C34S, SO2, C2H and c−C3H2 molecular transitions with the Atacama Large Millimeter/submillimeter Array (ALMA) at wavelengths of 0.8 mm. The spectrally and spatially resolved maps reveal the kinematics of the circumbinary disk as well as its chemistry. Molecular abundances are estimated using the non-local thermodynamic equilibrium (LTE) radiative-transfer tool RADEX. Results. The continuum emission agrees with the position of Oph-IRS67 A and B, and reveals the presence of a circumbinary disk around the two sources. The circumbinary disk has a diameter of ~620 AU and is well traced by C17O and H13CO+ emission. Two further molecular species, C2H and c−C3H2, trace a higher-density region which is spatially offset from the sources (~430 AU). Finally, SO2 shows compact and broad emission around only one of the sources, Oph-IRS67 B. The molecular transitions which trace the circumbinary disk are consistent with a Keplerian profile on smaller disk scales (≲200 AU) and an infalling profile for larger envelope scales (≳200 AU). The Keplerian fit leads to an enclosed mass of 2.2 M⊙. Inferred CO abundances with respect to H2 are comparable to the canonical ISM value of 2.7 × 10−4, reflecting that freeze-out of CO in the disk midplane is not significant. Conclusions. Molecular emission and kinematic studies prove the existence and first detection of the circumbinary disk associated with the system Oph-IRS67. The high-density region shows a different chemistry than the disk, being enriched in carbon chain molecules. The lack of methanol emission agrees with the scenario where the extended disk dominates the mass budget in the innermost regions of the protostellar envelope, generating a flat density profile where less material is exposed to high temperatures, and thus, complex organic molecules would be associated with lower column densities. Finally, Oph-IRS67 is a promising candidate for proper motion studies and the detection of both circumstellar disks with higher-angular-resolution observations.

scholarly journals Gas flow and accretion via spiral streamers and circumstellar disks in a young binary protostar

Science ◽  
2019 ◽  
Vol 366 (6461) ◽  
pp. 90-93 ◽  
Author(s):  
F. O. Alves ◽  
P. Caselli ◽  
J. M. Girart ◽  
D. Segura-Cox ◽  
G. A. P. Franco ◽  
...  
Keyword(s):  
Gas Flow ◽  
Angular Resolution ◽  
Complex Structure ◽  
Circumstellar Disks ◽  
Orbital Evolution ◽  
High Angular Resolution ◽  
Stellar Systems ◽  
Lower Mass ◽  
Radio Jets ◽  
Theoretical Predictions

The majority of stars are part of gravitationally bound stellar systems, such as binaries. Observations of protobinary systems constrain the conditions that lead to stellar multiplicity and subsequent orbital evolution. We report high–angular resolution observations of the circumbinary disk around [BHB2007] 11, a young binary protostar system. The two protostars are embedded in circumstellar disks that have radii of 2 to 3 astronomical units and probably contain a few Jupiter masses. These systems are surrounded by a complex structure of filaments connecting to the larger circumbinary disk. We also observe accretion and radio jets associated with the protobinary system. The accretion is preferentially onto the lower-mass protostar, consistent with theoretical predictions.

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