Related papers: Lack of other molecules in CO-rich debris discs: i…
According to the current paradigm of circumstellar disk evolution, gas-rich primordial disks evolve into gas-poor debris disks compose of second-generation dust. To explore the transition between these phases, we searched for $^{12}$CO,…
The detection of gas in debris disks raises the question of whether this gas is a remnant from the primordial protoplanetary phase, or released by the collision of secondary bodies. In this paper we analyze ALMA observations at 1-1.5"…
Debris discs represent the last stages of planet formation and as such are expected to be depleted of primordial gas. Nonetheless, in the last few years the presence of cold gas has been reported in $\sim$ 20 debris discs from far-IR to…
The origin and evolution of gas in debris disks is still not well understood. Secondary gas production from cometary material or a primordial origin have been proposed. So far, observations have mostly concentrated on CO, with only few C…
Over the past fifteen years, surveys mainly at millimeter wavelengths have led to the discovery of $\sim$20 gas-bearing debris disks, most of them surrounding young intermediate-mass stars. Exploring the properties and origin of this gas…
The origin and evolution of CO gas in debris disks has been debated since its initial detection. The gas could have a primordial origin, as a remnant of the protoplanetary disk or a secondary exocometary origin. This paper investigates the…
Despite being $>10$Myr, there are $\sim$10 debris discs with as much CO gas as in protoplanetary discs. Such discs have been assumed to be "hybrid", i.e., with secondary dust but primordial gas. Here we show that both the dust and gas in…
This paper uses observations of dusty debris discs, including a growing number of gas detections in these systems, to test our understanding of the origin and evolution of this gaseous component. It is assumed that all debris discs with icy…
[abridged]CO rovibrational lines are efficient probes of warm molecular gas and can give unique insights into the inner 10 AU of proto-planetary disks. Recent studies have found a relation between the ratio of lines originating from the…
Over 20 exocometary belts host detectable circumstellar gas, mostly in the form of CO. Two competing theories for its origin have emerged, positing the gas to be primordial or secondary. Primordial gas survives from the belt's parent…
One of the defining properties of debris discs compared to protoplanetary discs used to be their lack of gas, yet small amounts of gas have been found around an increasing number of debris discs in recent years. These debris discs found to…
Previous observations revealed the existence of CO gas at nearly protoplanetary level in several dust-rich debris disks around young A-type stars. Here we used the ALMA 7m-array to measure $^{13}$CO and C$^{18}$O emission toward two debris…
The increased sensitivity of millimeter-wave facilities now makes possible the detection of low amounts of gas in debris disks. Some of the gas-rich debris disks harbor peculiar properties, with possible pristine gas and secondary generated…
An increasing number of observations have shown that gaseous debris discs are not an exception. However, until now we only knew of cases around A stars. Here we present the first detection of 12CO (2-1) disc emission around an F star, HD…
Surprisingly strong CO emission has been observed from more than a dozen debris disks around nearby main-sequence stars. The origin of this CO is unclear, in particular whether it is left over from the protoplanetary disk phase or is…
We observed a sample of 20 representative Herbig Ae/Be stars and five A-type debris discs with PACS onboard of Herschel. The observations were done in spectroscopic mode, and cover far-IR lines of [OI], [CII], CO, CH+, H2O and OH. We have a…
Protoplanetary disks around Herbig AeBe stars are exciting targets for studying the chemical environments where giant planets form. Save for a few disks, however, much of Herbig AeBe disk chemistry is an open frontier. We present a…
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…
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…
H$_2$CO is one of the most abundant organic molecules in protoplanetary disks and can serve as a precursor to more complex organic chemistry. We present an ALMA survey of H$_2$CO towards 15 disks covering a range of stellar spectral types,…