Related papers: Deuterium-burning in substellar objects
Deuterium was primarily created during the Big Bang Nucleosynthesis (BBN). This fact, alongside its fractionation reactions resulting in enhanced abundances of deuterated molecules, means that these abundances can be used to better…
The process that leads to the formation and early evolution of low-mass stars is in a broad sense well understood theoretically and carefully traced observationally. The largest uncertainties in this framework reside in the poorly known…
An accurate value of the deuterium/hydrogen (D/H) ratio in the local interstellar medium (LISM) and a better understanding of the D/H variations with position in the Galactic disk can provide essential information on the primordial D/H…
Context. Deuterium in H-bearing species is enhanced during the early stages of star formation, however, only a small number of high spatial resolution deuteration studies exist towards protostellar objects, leaving the small-scale…
H2S is thought to be the main sulphur reservoir in the ice, being therefore a key molecule to understand sulphur chemistry in the star formation process and to solve the missing sulphur problem. The H2S deuterium fraction can be used to…
Observations of low mass protostars which probe small enough size scales to be within likely CO depletion regions show the highest [NH2D]/[NH3] ratios yet measured, of 4--33%. These molecular D/H ratios are higher than those measured on…
The depletion of lithium during the pre-main sequence and main sequence phases of stellar evolution plays a crucial role in the comparison of the predictions of big bang nucleosynthesis with the abundances observed in halo stars. In the…
We study deuterium fractionation in two massive starless/early-stage cores C1-N and C1-S in Infrared Dark Cloud (IRDC) G028.37+00.07, first identified by Tan et al. (2013) with ALMA. Line emission from multiple transitions of $\rm N_2H^+$…
We propose a new mechanism by which dark matter (DM) can affect the early universe. The hot interior of a macroscopic DM, or macro, can behave as a heat reservoir so that energetic photons are emitted from its surface. This results in…
The H3+ ion plays a key role in the chemistry of dense interstellar gas clouds where stars and planets are forming. The low temperatures and high extinctions of such clouds make direct observations of H3+ impossible, but lead to large…
The primordial abundance of deuterium produced during Big Bang Nucleosynthesis (BBN) depends sensitively on the universal ratio of baryons to photons, an important cosmological parameter probed independently by the Cosmic Microwave…
We find no evidence for the presence of genuinely young galaxies in our Local universe. We argue that the metal deficiencies and the behavior of the N/O and C/O ratios meet several plausible explanations involving the primary and secondary…
We quantify the gas-phase abundance of deuterium and fractional contribution of stellar mass loss to the gas in cosmological zoom-in simulations from the Feedback In Realistic Environments project. At low metallicity, our simulations…
Young massive stars are usually found embedded in dense and massive molecular clumps and are known for being highly obscured and distant. During their formation process, deuteration is regarded as a potentially good indicator of the…
We present N2D+ 3-2 (IRAM) and H2D+ 1_11 - 1_10 and N2H+ 4-3 (JCMT) maps of the small cluster-forming Ophiuchus B2 core in the nearby Ophiuchus molecular cloud. In conjunction with previously published N2H+ 1-0 observations, the N2D+ data…
A spectral evolution model of galaxies that includes both stellar and dust effects is newly built. xApplying the model to 22 nearby starburst galaxies, we have shown that far infrared luminosity of galaxies helps to break the age-dustiness…
Deuterium enhancement of monodeuterated species has been recognized for more than 30 years as a result of the chemical fractionation that results from the difference in zero point energies of deuterated and hydrogenated molecules. The key…
We provide a review of the current status of several topics on the ages, distances, and mass functions of open clusters, with a particular emphasis on illuminating the areas of uncertainty. Hipparcos has obtained parallaxes for nearby open…
This overview summarizes the age dating methods available for young sub-solar mass stars. Pre-main sequence age diagnostics include the Hertzsprung-Russell (HR) diagram, spectroscopic surface gravity indicators, and lithium depletion;…
We present the results of our studies of deuterated molecules (DCN, DNC, DCO$^+$, N$_2$D$^+$ and NH$_2$D) in regions of high-mass star formation, which include a survey of such regions with the 20-m Onsala radio telescope and mapping of…