Related papers: An ALMA Survey for Disks Orbiting Low-Mass Stars i…
We present a detailed analysis of the spatially and spectrally resolved 12CO J=2-1 and J=3-2 emission lines from the TW Hya circumstellar disk, based on science verification data from the Atacama Large Millimeter/Submillimeter Array (ALMA).…
A search for previously undetected optically thin disks around stars in the nearby, young, TW Hydrae Association was conducted around sixteen stars with sensitive 12 and 18 micron photometry. The survey could detect Zodiacal-like dust, with…
The 30 Myr old A3-type star HD 21997 is one of the two known debris dust disks having a measurable amount of cold molecular gas. With the goal of understanding the physical state, origin, and evolution of the gas in young debris disks, we…
We present results from an Atacama Large Millimeter/submillimeter Array (ALMA) Cycle 2 program to map CO(2-1) emission in nearby early-type galaxies (ETGs) that host circumnuclear gas disks. We obtained $\sim0.3''-$resolution Band 6…
We report the first detection of a gap and a ring in 336 GHz dust continuum emission from the protoplanetary disk around TW Hya, using the Atacama Large Millimeter/Submillimeter Array (ALMA). The gap and ring are located at around 25 and 41…
The radial extent of millimetre dust in protoplanetary discs is often far smaller than that of their gas, mostly due to processes such as dust growth and radial drift. However, it has been suggested that current millimetre continuum…
Debris disks can be seen as the left-overs of giant planet formation and the possible nurseries of rocky planets. While M-type stars out-number more massive stars we know very little about the time evolution of their circumstellar disks at…
We carried out a 12CO(3-2) survey of 52 southern stars with a wide range of IR excesses (LIR/L*) using the single dish telescopes APEX and ASTE. The main aims were (1) to characterize the evolution of molecular gas in circumstellar disks…
CO is widely used as a tracer of molecular gas. However, there is now mounting evidence that gas phase carbon is depleted in the disk around TW Hya. Previous efforts to quantify this depletion have been hampered by uncertainties regarding…
We present Atacama Large Millimeter Array (ALMA) observations of TW Hya at 3.1 mm with $\sim50$ milliarcsecond resolution. These new data were combined with archival high angular resolution ALMA observations at 0.87 mm, 1.3 mm, and 2.1 mm.…
We aim to estimate if structures, such as cavities, rings, and gaps, are common in disks around VLMS and to test models of structure formation in these disks. We also aim to compare the radial extent of the gas and dust emission in disks…
Circumstellar disks around stars older than 10 Myr are expected to be gas-poor. There are, however, two examples of old (30-40 Myr) debris-like disks containing a detectable amount of cold CO gas. Here we present ALMA and Herschel Space…
We present photometric detections of dust emission at 850 and 450 micron around the pre-main sequence M1 dwarf TWA 7 using the SCUBA camera on the James Clerk Maxwell Telescope. These data confirm the presence of a cold dust disk around TWA…
Using HST-COS FUV spectra, we have discovered warm molecular hydrogen in the TWA 7 system. TWA 7, a $\sim$9 Myr old M2.5 star, has a cold debris disk and has previously shown no signs of accretion. Molecular hydrogen is expected to be…
We analyze high angular resolution ALMA observations of the TW Hya disk to place constraints on the CO and dust properties. We present new, sensitive observations of the $^{12}$CO $J = 3-2$ line at a spatial resolution of 8 AU (0\farcs14).…
We present ALMA observations of 106 G-, K-, and M-type stars in the Upper Scorpius OB Association hosting circumstellar disks. With these data, we measure the 0.88 mm continuum and $^{12}$CO $J$ = 3$-$2 line fluxes of disks around low-mass…
We present long-baseline Atacama Large Millimeter/submillimeter Array (ALMA) observations of the 870 micron continuum emission from the nearest gas-rich protoplanetary disk, around TW Hya, that trace millimeter-sized particles down to…
T Cha is a young star surrounded by a transitional disk with signatures of planet formation. We have obtained high-resolution and high-sensitivity ALMA observations of T Cha in the ${\rm CO}(3$--$2)$, ${\rm ^{13}CO}(3$--$2)$, and ${\rm…
We present molecular line observations of 13CO and C18O J=3-2, CN N = 3 - 2, and CS J=7-6 lines in the protoplanetary disk around TW Hya at a high spatial resolution of ~9 au (angular resolution of 0.15''), using the Atacama Large…
In the past decade, the Atacama Large Millimeter/submillimeter Array (ALMA) has revealed a plethora of substructures in the disks surrounding young stars. These substructures have several proposed formation mechanisms, with one leading…