Browsing by Author "Testi, Leonardo"

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    Chemical and Physical Characterization of the Isolated Protostellar Source CB68: FAUST IV
    (IOP Publishing, 2022) Imai, Muneaki; Oya, Yoko; Svoboda, Brian; Liu, Hauyu Baobab; Lefloch, Bertrand; Viti, Serena; Zhang, Yichen; Ceccarelli, Cecilia; Codella, Claudio; Chandler, Claire J.; Sakai, Nami; Aikawa, Yuri; Alves, Felipe O.; Balucani, Nadia; Bianchi, Eleonora; Bouvier, Mathilde; Busquet, Gemma; Caselli, Paola; Caux, Emmanuel; Charnley, Steven; Choudhury, Spandan; Cuello, Nicolas; Simone, Marta De; Dulieu, Francois; Durán, Aurora; Evans, Lucy; Favre, Cécile; Fedele, Davide; Feng, Siyi; Fontani, Francesco; Francis, Logan; Hama, Tetsuya; Hanawa, Tomoyuki; Herbst, Eric; Hirano, Shingo; Hirota, Tomoya; Isella, Andrea; Jímenez-Serra, Izaskun; Johnstone, Doug; Kahane, Claudine; Gal, Romane Le; Loinard, Laurent; López-Sepulcre, Ana; Maud, Luke T.; Maureira, María José; Menard, Francois; Mercimek, Seyma; Miotello, Anna; Moellenbrock, George; Mori, Shoji; Murillo, Nadia M.; Nakatani, Riouhei; Nomura, Hideko; Oba, Yasuhiro; O'Donoghue, Ross; Ohashi, Satoshi; Okoda, Yuki; Ospina-Zamudio, Juan; Pineda, Jaime; Podio, Linda; Rimola, Albert; Sakai, Takeshi; Segura-Cox, Dominique; Shirley, Yancy; Taquet, Vianney; Testi, Leonardo; Vastel, Charlotte; Watanabe, Naoki; Watanabe, Yoshimasa; Witzel, Arezu; Xue, Ci; Zhao, Bo; Yamamoto, Satoshi
    The chemical diversity of low-mass protostellar sources has so far been recognized, and environmental effects are invoked as its origin. In this context, observations of isolated protostellar sources without the influence of nearby objects are of particular importance. Here, we report the chemical and physical structures of the low-mass Class 0 protostellar source IRAS 16544−1604 in the Bok globule CB 68, based on 1.3 mm Atacama Large Millimeter/submillimeter Array observations at a spatial resolution of ∼70 au that were conducted as part of the large program FAUST. Three interstellar saturated complex organic molecules (iCOMs), CH3OH, HCOOCH3, and CH3OCH3, are detected toward the protostar. The rotation temperature and the emitting region size for CH3OH are derived to be 131 ± 11 K and ∼10 au, respectively. The detection of iCOMs in close proximity to the protostar indicates that CB 68 harbors a hot corino. The kinematic structure of the C18O, CH3OH, and OCS lines is explained by an infalling–rotating envelope model, and the protostellar mass and the radius of the centrifugal barrier are estimated to be 0.08–0.30 M ⊙ and <30 au, respectively. The small radius of the centrifugal barrier seems to be related to the small emitting region of iCOMs. In addition, we detect emission lines of c-C3H2 and CCH associated with the protostar, revealing a warm carbon-chain chemistry on a 1000 au scale. We therefore find that the chemical structure of CB 68 is described by a hybrid chemistry. The molecular abundances are discussed in comparison with those in other hot corino sources and reported chemical models.
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    Misaligned Rotations of the Envelope, Outflow, and Disks in the Multiple Protostellar System of VLA 1623–2417: FAUST. III
    (IOP Publishing, 2022) Ohashi, Satoshi; Codella, Claudio; Sakai, Nami; Chandler, Claire J.; Ceccarelli, Cecilia; Alves, Felipe; Fedele, Davide; Hanawa, Tomoyuki; Durán, Aurora; Favre, Cécile; López-Sepulcre, Ana; Loinard, Laurent; Mercimek, Seyma; Murillo, Nadia M.; Podio, Linda; Zhang, Yichen; Aikawa, Yuri; Balucani, Nadia; Bianchi, Eleonora; Bouvier, Mathilde; Busquet, Gemma; Caselli, Paola; Caux, Emmanuel; Charnley, Steven; Choudhury, Spandan; Cuello, Nicolas; Simone, Marta De; Dulieu, Francois; Evans, Lucy; Feng, Siyi; Fontani, Francesco; Francis, Logan; Hama, Tetsuya; Herbst, Eric; Hirano, Shingo; Hirota, Tomoya; Imai, Muneaki; Isella, Andrea; Jímenez-Serra, Izaskun; Johnstone, Doug; Kahane, Claudine; Gal, Romane Le; Lefloch, Bertrand; Maud, Luke T.; Maureira, María José; Menard, Francois; Miotello, Anna; Moellenbrock, George; Mori, Shoji; Nakatani, Riouhei; Nomura, Hideko; Oba, Yasuhiro; O'Donoghue, Ross; Okoda, Yuki; Ospina-Zamudio, Juan; Oya, Yoko; Pineda, Jaime; Rimola, Albert; Sakai, Takeshi; Segura-Cox, Dominique; Shirley, Yancy; Svoboda, Brian; Taquet, Vianney; Testi, Leonardo; Vastel, Charlotte; Viti, Serena; Watanabe, Naoki; Watanabe, Yoshimasa; Witzel, Arezu; Xue, Ci; Zhao, Bo; Yamamoto, Satoshi
    We report a study of the low-mass Class 0 multiple system VLA 1623AB in the Ophiuchus star-forming region, using H13CO+ (J = 3–2), CS (J = 5–4), and CCH (N = 3–2) lines as part of the ALMA Large Program FAUST. The analysis of the velocity fields revealed the rotation motion in the envelope and the velocity gradients in the outflows (about 2000 au down to 50 au). We further investigated the rotation of the circumbinary VLA 1623A disk, as well as the VLA 1623B disk. We found that the minor axis of the circumbinary disk of VLA 1623A is misaligned by about 12° with respect to the large-scale outflow and the rotation axis of the envelope. In contrast, the minor axis of the circumbinary disk is parallel to the large-scale magnetic field according to previous dust polarization observations, suggesting that the misalignment may be caused by the different directions of the envelope rotation and the magnetic field. If the velocity gradient of the outflow is caused by rotation, the outflow has a constant angular momentum and the launching radius is estimated to be 5–16 au, although it cannot be ruled out that the velocity gradient is driven by entrainments of the two high-velocity outflows. Furthermore, we detected for the first time a velocity gradient associated with rotation toward the VLA 16293B disk. The velocity gradient is opposite to the one from the large-scale envelope, outflow, and circumbinary disk. The origin of its opposite gradient is also discussed.
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    Multiple chemical tracers finally unveil the intricate NGC 1333 IRAS 4A outflow system. FAUST XVI
    (Oxford University Press, 2024) Chahine, Layal; Ceccarelli, Cecilia; De Simone, Marta; Chandler, Claire J; Codella, Claudio; Podio, Linda; López-Sepulcre, Ana; Sakai, Nami; Loinard, Laurent; Bouvier, Mathilde; Caselli, Paola; Vastel, Charlotte; Bianchi, Eleonora; Cuello, Nicolás; Fontani, Francesco; Johnstone, Doug; Sabatini, Giovanni; Hanawa, Tomoyuki; Zhang, Ziwei E; Aikawa, Yuri; Busquet, Gemma; Caux, Emmanuel; Durán, Aurore; Herbst, Eric; Ménard, François; Segura-Cox, Dominique; Svoboda, Brian; Balucani, Nadia; Charnley, Steven; Dulieu, François; Evans, Lucy; Fedele, Davide; Feng, Siyi; Hama, Tetsuya; Hirota, Tomoya; Isella, Andrea; Jímenez-Serra, Izaskun; Lefloch, Bertrand; Maud, Luke T; Maureira, María José; Miotello, Anna; Moellenbrock, George; Nomura, Hideko; Oba, Yasuhiro; Ohashi, Satoshi; Okoda, Yuki; Oya, Yoko; Pineda, Jaime; Rimola, Albert; Sakai, Takeshi; Shirley, Yancy; Testi, Leonardo; Viti, Serena; Watanabe, Naoki; Watanabe, Yoshimasa; Zhang, Yichen; Yamamoto, Satoshi
    The exploration of outflows in protobinary systems presents a challenging yet crucial endeavour, offering valuable insights into the dynamic interplay between protostars and their evolution. In this study, we examine the morphology and dynamics of jets and outflows within the IRAS 4A protobinary system. This analysis is based on ALMA observations of SiO(5–4), H2CO(30, 3–20, 3), and HDCO(41, 4–31, 3) with a spatial resolution of ∼150 au. Leveraging an astrochemical approach involving the use of diverse tracers beyond traditional ones has enabled the identification of novel features and a comprehensive understanding of the broader outflow dynamics. Our analysis reveals the presence of two jets in the redshifted emission, emanating from IRAS 4A1 and IRAS 4A2, respectively. Furthermore, we identify four distinct outflows in the region for the first time, with each protostar, 4A1 and 4A2, contributing to two of them. We characterize the morphology and orientation of each outflow, challenging previous suggestions of bends in their trajectories. The outflow cavities of IRAS 4A1 exhibit extensions of 10 and 13 arcsec with position angles (PA) of 0° and -12°, respectively, while those of IRAS 4A2 are more extended, spanning 18 and 25 arcsec with PAs of 29° and 26°. We propose that the misalignment of the cavities is due to a jet precession in each protostar, a notion supported by the observation that the more extended cavities of the same source exhibit lower velocities, indicating they may stem from older ejection events.
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    Resolved ALMA observations of water in the inner astronomical units of the HL Tau disk
    (Springer Nature, 2024) Facchini, Stefano; Testi, Leonardo; Humphreys, Elizabeth; Vander Donckt, Mathieu; Isella, Andrea; Wrzosek, Ramon; Baudry, Alain; Gray, Malcom D.; Richards, Anita M. S.; Vlemmmings, Wouter
    The water molecule is a key ingredient in the formation of planetary systems, with the water snowline being a favourable location for the growth of massive planetary cores. Here we present Atacama Large Millimeter/submillimeter Array data of the ringed protoplanetary disk orbiting the young star HL Tauri that show centrally peaked, bright emission arising from three distinct transitions of the main water isotopologue ($${\mathrm{H}}_{2}^{16}{\mathrm{O}}$$). The spatially and spectrally resolved water content probes gas in a thermal range down to the water sublimation temperature. Our analysis implies a stringent lower limit of 3.7 Earth oceans of water vapour available within the inner 17 astronomical units of the system. We show that our observations are limited to probing the water content in the atmosphere of the disk, due to the high dust column density and absorption, and indicate that the main water isotopologue is the best tracer to spatially resolve water vapour in protoplanetary disks.
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    Ringed Structures of the HD 163296 Protoplanetary Disk Revealed by ALMA
    (American Physical Society, 2016) Isella, Andrea; Guidi, Greta; Testi, Leonardo; Liu, Shangfei; Li, Hui; Li, Shengtai; Weaver, Erik; Boehler, Yann; Carperter, John M.; De Gregorio-Monsalvo, Itziar; Manara, Carlo F.; Natta, Antonella; Pérez, Laura M.; Ricci, Luca; Sargent, Anneila; Tazzari, Marco; Turner, Neal
    We present Atacama Large Millimeter and Submillimeter Array observations of the protoplanetary disk around the Herbig Ae star HD 163296 that trace the spatial distribution of millimeter-sized particles and cold molecular gas on spatial scales as small as 25 astronomical units (A.U.). The image of the disk recorded in the 1.3 mm continuum emission reveals three dark concentric rings that indicate the presence of dust depleted gaps at about 60, 100, and 160 A.U. from the central star. The maps of the 12CO, 13CO, and C18O J=2−1 emission do not show such structures but reveal a change in the slope of the radial intensity profile across the positions of the dark rings in the continuum image. By comparing the observations with theoretical models for the disk emission, we find that the density of CO molecules is reduced inside the middle and outer dust gaps. However, in the inner ring there is no evidence of CO depletion. From the measurements of the dust and gas densities, we deduce that the gas-to-dust ratio varies across the disk and, in particular, it increases by at least a factor 5 within the inner dust gap compared to adjacent regions of the disk. The depletion of both dust and gas suggests that the middle and outer rings could be due to the gravitational torque exerted by two Saturn-mass planets orbiting at 100 and 160 A.U. from the star. On the other hand, the inner dust gap could result from dust accumulation at the edge of a magnetorotational instability dead zone, or from dust opacity variations at the edge of the CO frost line. Observations of the dust emission at higher angular resolution and of molecules that probe dense gas are required to establish more precisely the origins of the dark rings observed in the HD 163296 disk.
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    The population of young low-mass stars in Trumpler 14
    (edp Sciences, 2024) Itrich, Dominika; Testi, Leonardo; Beccari, Giacomo; Manara, Carlo F.; Reiter, Megan; Preibisch, Thomas; McLeod, Anna F.; Rosotti, Giovanni; Klessen, Ralf; Molinari, Sergio; Hennebelle, Patrick
    Massive star-forming regions are thought to be the most common birth environments in the Galaxy and the only birth places of very massive stars. Their presence in the stellar cluster alters the conditions within the cluster, impacting at the same time the evolution of other cluster members. In principle, copious amounts of ultraviolet radiation produced by massive stars can remove material from outer parts of the protoplanetary discs around low- and intermediate-mass stars in the process of external photoevaporation, effectively reducing the planet formation capabilities of those discs. Here, we present deep VLT/MUSE observations of low-mass stars in Trumpler 14, one of the most massive, young, and compact clusters in the Carina Nebula Complex. We provide spectral and stellar properties of 717 sources and based on the distribution of stellar ages, derive the cluster age of ∼1 Myr. The majority of the stars in our sample have masses ≤1 M⊙, which makes our spectroscopic catalogue the deepest to date in term of mass and proves that detailed investigations of low-mass stars are possible in the massive but distant regions. Spectroscopic studies of low-mass members of the whole Carina Nebula Complex are missing. Our work marks an important step forward towards filling this gap and sets the stage for follow-up investigations of accretion properties in Trumpler 14.