In the collapsing phase of a molecular cloud, the molecular gas temperature is a key to understand the evolutionary process from a dense molecular cloud to stars. In order to know this, mapping observations in NH3 lines are required. Therefore, we made them based on the FUGIN (FOREST Unbiased Galactic plane Imaging survey with Nobeyama 45m telescope). The 6 maps were observed in NH3 (J,K) = (1,1), (2,2), (3,3) and H2O maser lines and obtained temperature maps; some show temperature gradient in a cloud. Additionally 72 cores were observed. These candidates were called as KAGONMA or KAG objects as abbreviation of KAgoshima Galactic Object survey with Nobeyama 45-M telescope in Ammonia lines. We show the results of two regions in W33 and discuss their astrophysical properties.

In this work, we carry out two-fluid (gas+dust) hydrodynamical simulations on a large family of models in order to study the dust coagulation and the dust-gas dynamical processes in protoplanetary disks. Our theoretical effort is guided by the observational results of disks in nearby star forming regions at sub-millimeter and millimeter (mm) wavelengths. By a systematic comparison with the continuum emission at several mm bands from ALMA observations, we find that ringed structures are predicated in the unresolved faint disks for those with mm spectral indexes as low as about 2.0. Our parameter exploration can also be used to constrain the fragmentation velocity, one key parameter of the dust coagulation model, and some other disk parameters.

Thousands of planets outside the Solar system have been discovered, with exoplanets in different environments. Since we cannot expect to find an exoplanetary system fully resembling our Solar System, we consider a Solar System type configuration where the Earth moves in an eccentric orbit. We focus on young Earth 1 billion years ago, when the Sun’s extreme UV (EUV) flux was about 5 times higher than the current radiation. In case of eccentric motion of Earth, strong variations of the EUV flux would influence the evolution of the planet’s atmosphere (EUV radiation of 50 times the current EUV flux would be possible). Taking into account a certain amount of Nitrogen in the atmosphere of such a young Earth, we study the non-thermal loss of N2 over a long time interval. We therefore investigate to what extent eccentric motion will influence the conditions of habitability of a terrestrial planet.

It is thought that protoplanets formed in protoplanetary disks excite the orbital motion of the surrounding planetesimals, and the bow shocks caused by the highly excited planetesimals heat their icy component evaporating into gas. We have performed model calculations to study the evolution of molecular abundances of the evaporated icy component, which suggests sulfur-bearing molecules can be good tracers of icy planetesimal evaporation. Here we report the result of our ALMA observations of sulfur-bearing molecules towards protoplanetary disks. The lines were undetected but the obtained upper limits of the line fluxes and our model calculations give upper limits of the fractional abundances of x(H2S) < 10−11 and x(SO) < 10−10 in the outer disk. These results are consistent with the molecular abundances in comets in our Solar system.

High spatial resolution observations with ALMA and VLT/SPHERE show gaps and rings in continuum emission of protoplanetary disks, possibly indicating ongoing planet formation. However, it is still unclear if the gas follows the dust distribution. We present radiation thermo-chemical models for the disk of HD 163296 to study the impact of dust and gas gaps on the chemistry and molecular line emission. We compare a model with only dust gaps to a model that also has gas gaps. In both models, rings and gaps are visible in (sub)mm molecular line emission. Due to chemistry, certain molecules are sensitive to dust gaps where others are more sensitive to gas depletion. Observations of multiple molecules might allow to accurately determine the degree of gas depletion within the dust gaps, information crucial to discriminate between gap formation theories (e.g. planets, ice lines).

The building blocks of planets in planet-forming (“protoplanetary”) disks are assembled early in the lifetime of a young star. The gas disks are relatively short-lived, with a half-life of about 3 million years, as chemical reactions modify the reservoir of material from the natal molecular cloud. Spitzer Space Telescope Infrared Spectrograph (IRS) spectra of protoplanetary disks around T Tauri stars show emission from H2O and absorption from other gases, sometimes consistent with formaldehyde, H2CO , and other times consistent with formic acid, HCOOH, in the 5-7.5 μm region. SOFIA-EXES spectra of YSOs that follow up on these Spitzer-IRS studies are presented. How the gaseous features observed between 5-7.5 μm relate to those at other wavelengths is discussed. This work suggests that water and organic molecules, which are crucial for life as we know it, are present in the habitable zones of stars at a very early age [of 1-3 million years].

Luminosity outbursts of the FU Ori type stars, which have a magnitude of ∼ 100 L⊙ and last for decades, may affect chemical composition of the surrounding protoplanetary disk. Using astrochemical modelling we analyse the changes induced by the outburst and search for species sensitive to the luminosity rise. Some changes in the disk molecular composition appear not only during the outburst itself but can also retain for decades after the end of the outburst. We analyse main chemical processes responsible for these effects and assess timescales at which chemically inert species return to the pre-outburst abundances.

A long-standing problem of the general paradigm of low-mass star formation is the “luminosity problem”: protostars are less luminous than theoretically predicted. One possible solution is that the accretion process is episodic. FU Orionis-type stars (FUors) are thought to be the visible examples for objects in the high accretion state and it is still debated what physical mechanism triggers the phenomenon. For many of these objects their disk properties are still largely unknown so we conducted a deep, high spatial resolution (down to 20 au) ALMA Band 6 (1.3 mm) dust continuum survey of a sub-sample of known FUors. Here we present preliminary results of our survey, including the mass, size and spectral slope of each disk.

Recent theories on the formation of the Solar System turned the attention to the study of low mass cloud cores in massive star forming regions. The Rosette Molecular Cloud is a well-known star forming area having highly filamentary structure with dense cores covering a wide range of masses. These pre- and protostellar cores were observed by Herschel and key core properties were derived from its data. With the Effelsberg 100m telescope a sample of these cores with masses ranging between 3-40 M⊙ were observed in ammonia inversion lines. In this work we are examining the correlations between these two datasets with the aim of gaining insight of the processes behind the star formation of the region.

The Planck all-sky submillimetre observations have made it possible to study Galactic cold clumps in diverse environments, to probe dust properties and to examine the earliest stages of star formation. The TOP-SCOPE joint survey program aims to statistically study the evolution of molecular clouds and the initial conditions of star formation in a wide variety of environments. In this work we carry out an investigation of the 200 brightest compact sources detected by Planck.

The origin of optical-infrared variability in young, intermediate mass Herbig Ae/Be stars is linked to their circumstellar disk. Therefore, variability could serve as a diagnostic tool to constrain the structure and dynamics of the (inner) disk. Here we discuss this diagnostic potential, and report some preliminary results from our coordinated BV RIJHKs and Spitzer monitoring observations of nine Herbig Ae stars. We aim to understand the response of the inner disks thermal emission on the changing stellar irradiation, and to separate it from UX Orionis-type fading events, which also provide information on the disk. This project is a pilot study for the era of time domain astronomy of young stars, opened by Kepler K2, Gaia, ASAS-SN, TESS, Spitzer, WISE, and JWST.

Our aim is to present a new and so far most complete catalog of optically selected young stars. The basis of this work is an extensive literature search for young stars in all the known nearby (< 2 kpc) star forming regions, included in the Handbook of Star Forming Regions [4, 5], and in 67 additional catalogs. We collected data on known young, pre-main-sequence stars detected in optical bands. The catalog contains the celestial coordinates, object names, names of the enclosing star forming region, identification methods, distances, and other information (e.g., references, binarity) for 15208 young stellar objects. It is already in use by the Gaia Photometric Science Alerts Team to identify variable young stars in the Gaia data. Our catalog was cross-correlated with the Gaia DR2 and we obtained flux and distance estimations for 86% of the stars.

Young stellar objects often show photometric variability, which is well examined at optical wavelengths, but more and more infrared data are also available. The wavelength dependence of the variability carries information on the physical cause of the changing brightness. Here, we examine seven T Tauri-type stars known for their large amplitude variability selected from the Campaign 13 field of the Kepler K2 mission. We complemented the K2 light curves by multifilter optical monitoring observations made with the 90 cm Schmidt telescope of Konkoly Observatory, and by 3.6 and 4.5 μm infrared photometry with a 20 hours cadence using the Spitzer Space Telescope. We found that the wavelength dependence of the observed variability is not consistent with changing interstellar extinction. We suggest that the brightness changes are due to variable accretion, causing a variable illumination of the inner disk.

Wasp-31b is a planet of 0.48 Jupiter masses and 1.55 Jupiter radii, with orbital period of 3.4-days around a metal-poor, late-F-type, V = 11.7 dwarf star. The planet has a large atmospheric scale height that makes it a good target for transmission spectroscopy. Sing et al (2014) presented an optical and near-IR transmission spectrum of the atmosphere of WASP-31b obtained with the HST and show the presence of a strong potassium line. In contrast, Gibson et al. (2017) reports a spectrum of the atmosphere of WASP-31b, obtained with the FORS2 instrument on the VLT and find that there is no strong potassium line. Here, we take those two datasets and, using models, we try to find a case where both solutions are correct by considering different cloud scenarios.

Methylamine (CH3NH2) is the simplest amine and thought to be a potential interstellar precursor to the amino acid glycine (NH2CH2COOH). It is confirmed by the experimental work and in terms of exploration in the Solar system, CH3NH2 has been detected in two comets. However, in molecular clouds, a robust detection of CH3NH2 has been reported only for Sgr B2(N) so far, while a variety of complex organic molecules have been detected by radio observations in many star-forming regions. To search for CH3NH2, we used the ALMA Cycle 2 archival data toward Orion Kleinmann-Low nebula (Orion-KL) at Band 6 and found 5 candidate emission at the hot core region. By using the rotation diagram method, we evaluated its tentative column density and rotational temperature to be 4.9×10 cm−2 and 102 K, respectively.

Discovered periodic sublimation activity on four main-belt primitive asteroids led us to conclusions about possible origin of those and similar bodies (or their parent bodies) near or beyond the snow line in the early Solar System making incorporated in them a considerable water ice stock. Water differentiation of the bodies owing to 26A1 decay and their internal thermal evolution might have created conditions for water soluble organics and prebiotic compounds formation. Subsequent longtime periodic changing temperature and other physico-chemical parameters (due to spinning and moving around the Sun) in the near-surface layers of primitive asteroids have led probably to formation of more complex organic compounds of astrobiological significance.

The early evolution of Sun-like stars may be interspersed by energetic FU Orionis (FUor) type accretion outbursts. We analysed eight years of photometric and spectroscopic variability of V582 Aur, a bona fide FUor, in outburst. While the accretion rate derived from near-infrared measurements was constant, radical brightness changes occurred due to dust clumps crossing the line of sight. The brightness minima resemble the variability patterns of the UXor phenomenon. Orbiting density enhancements or short-lived clumps moving in and out of the line-of-sight may explain these observations. Our message is that during FUor outbursts the inner disk is a dynamically active place, affecting the initial conditions for planet formation.

Observationally locating the position of the H2O snowline in protoplanetary disks is crucial for understanding planetesimal and planet formation processes, and the origin of water on the Earth. In our studies, we conducted calculations of chemical reactions and water line profiles in protoplanetary disks, and identified that ortho/para-H216O, H218O lines with small Einstein A coefficients and relatively high upper state energies are dominated by emission from the hot midplane region inside the H2O snowline. Therefore, through analyzing their line profiles the position of the H2O snowline can be located. Moreover, because the number density of the H218O is much smaller than that of H216O, the H218O lines can trace deeper into the disk and thus they are potentially better probes of the exact position of the H2O snowline in disk midplane.