Searcharxiv⌕ Search
Home/Archive/arXiv

arXiv · 2610.28795

FAUST XXXII. Chemically layered structures and ionisation in the disk and envelope of NGC 1333 IRAS 4C

Shota Notsu·Nami Sakai·Yichen Zhang·Ana Lopez-Sepulcre·Claire J. Chandler·Ziwei E. Zhang·Cecilia Ceccarelli·Claudio Codella·Yuri Aikawa·Jaime E. Pineda·Brian Svoboda·Felipe O. Alves·Nadia Balucani·Eleonora Bianchi·Mathilde Bouvier·Gemma Busquet·Paola Caselli·Emmanuel Caux·Steven Charnley·Spandan Choudhury·Nicol as Cuello·Marta De Simone·Francois Dulieu·Aurora Duran·Lucy Evans·Cecile Favre·Siyi Feng·Davide Fedele·Francesco Fontani·Tetsuya Hama·Tomoyuki Hanawa·Eric Herbst·Shingo Hirano·Tomoya Hirota·Andrea Isella·Izaskun Jimenez-Serra·Doug Johnstone·Claudine Kahane·Romane Le Gal·Bertrand Lefloch·Laurent Loinard·Hauyu Baobab Liu·Antonio Martinez-Henares·Luke T. Maud·Maria Jose Maureira·Francois Menard·Seyma Mercimek·Anna Miotello·George Moellenbrock·Shoji Mori·Nadia M. Murillo·Riouhei Nakatani·Hideko Nomura·Yasuhiro Oba·Ross O'Donoghue·Satoshi Ohashi·Yuki Okoda·Juan Ospina-Zamudio·Yoko Oya·Linda Podio·Albert Rimola·Giovanni Sabatini·Takeshi Sakai·Dominique M. Segura-Cox·Yancy Shirley·Leonardo Testi·Charlotte Vastel·Serena Viti·Naoki Watanabe·Yoshimasa Watanabe·Arezu Witzel·Ci Xue·Bo Zhao·Satoshi Yamamoto
View original source ↗Read source document ↗Export metadata ↓

Abstract

Recent molecular line observations with high spatial resolutions have revealed vertical chemical stratification in Class I/II disks (i.e. chemical composition changing with height in the vertical direction of the disk), as well as a radial variation of ionisation rates. However, such chemical layered structures in Class 0 disk and envelope systems have been investigated only for limited objects, such as L1527. In the context of the ALMA Large Program FAUST, we report the results of molecular line observations toward the disk and envelope around the low-mass Class 0 protostar NGC 1333 IRAS 4C in the Perseus Molecular Cloud. Previous observations have shown that the disk rotation axis of this object is largely tilted to the line of sight, making it suitable for studying the molecular abundance distribution as a function of disk height. We found that the molecules known as gas density tracers such as C18O and H2CO are distributed around the disk midplane. In addition, molecules known as tracers of photochemical reactions such as CCH and c-C3H2 are distributed in the low-density upper layers of the disk, unlike the distribution in L1527. Moreover, the column density ratio of HCO+/CO derived from the H13CO+ and C18O line emission suggests that the ionisation degree and the ionisation rate vary with the disk radius and they are larger in the outer region of the disk and envelope.

Explore related subjects

astro-ph.EPastro-ph.GAastro-ph.SR

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Shota Notsu, Nami Sakai, Yichen Zhang, Ana Lopez-Sepulcre, Claire J. Chandler, Ziwei E. Zhang, Cecilia Ceccarelli, Claudio Codella, Yuri Aikawa, Jaime E. Pineda, Brian Svoboda, Felipe O. Alves, Nadia Balucani, Eleonora Bianchi, Mathilde Bouvier, Gemma Busquet, Paola Caselli, Emmanuel Caux, Steven Charnley, Spandan Choudhury, Nicol as Cuello, Marta De Simone, Francois Dulieu, Aurora Duran, Lucy Evans, Cecile Favre, Siyi Feng, Davide Fedele, Francesco Fontani, Tetsuya Hama, Tomoyuki Hanawa, Eric Herbst, Shingo Hirano, Tomoya Hirota, Andrea Isella, Izaskun Jimenez-Serra, Doug Johnstone, Claudine Kahane, Romane Le Gal, Bertrand Lefloch, Laurent Loinard, Hauyu Baobab Liu, Antonio Martinez-Henares, Luke T. Maud, Maria Jose Maureira, Francois Menard, Seyma Mercimek, Anna Miotello, George Moellenbrock, Shoji Mori, Nadia M. Murillo, Riouhei Nakatani, Hideko Nomura, Yasuhiro Oba, Ross O'Donoghue, Satoshi Ohashi, Yuki Okoda, Juan Ospina-Zamudio, Yoko Oya, Linda Podio, Albert Rimola, Giovanni Sabatini, Takeshi Sakai, Dominique M. Segura-Cox, Yancy Shirley, Leonardo Testi, Charlotte Vastel, Serena Viti, Naoki Watanabe, Yoshimasa Watanabe, Arezu Witzel, Ci Xue, Bo Zhao, Satoshi Yamamoto. 2026-10-20. FAUST XXXII. Chemically layered structures and ionisation in the disk and envelope of NGC 1333 IRAS 4C. https://arxiv.org/abs/2610.28795

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Saturn's Evolutionary History and Seismology: Survival of Deep Stably Stratified Regions in Evolutionary Models of Saturn Consistent with Ring Seismology

With recent advances in the modeling of the solar system giant planets, rapid progress has been made in understanding the remaining questions pertaining to their formation and evolution. However, this progress has largely neglected the significant constraints on the interior of Saturn's structure imposed by the observed oscillation frequencies in its rings. Here, we study initial conditions for Saturn's evolution that, after $4.56\;\mathrm{Gyr}$ of evolution, give rise to planetary structures admitting oscillation frequencies consistent with those observed via Saturn's ring seismology. Restricting our attention to models without compact rocky cores, we achieve simultaneous good agreement with most observed properties of Saturn at the level of current evolutionary models and with key frequencies in the observed oscillation spectrum. Our preliminary work suggests that Saturn's interior stably stratified region may be moderately less extended ($\sim 0.4$--$0.5R_{\rm Sat}$) than previously thought, which is important for reconciling the seismic constraints with evolutionary models. We also tentatively find that the deep helium gradients inferred by previous, static structural modelling of Saturn's ring seismology may not be required to reproduce the observed seismology data.

astro-ph.EP↗
arXiv2026

Addressing Exoplanetary Degeneracies Through Geometry: Application to Asynchronously Rotating Systems

This study augments the geometry-based InstellCa code that calculates accurate irradiance values to InstellCa--2, which computes the longitude averaged instellation over a given latitude on the planet along with its effective temperature profile. The estimation of instellation is performed considering the planet as a 3D body that asynchronously rotates, causing a varying zenith angle of the star resulting in a diurnal cycle. This serves as a specialised case study to demonstrate how the combination of this relative rotation and extreme proximity to host-stars can affect the estimated effective temperatures of close-in planets. 55 Cancri e is selected specifically to demonstrate the importance of this effect as it has been earlier hypothesised to exhibit asynchronous rotation and also has a debated scientific discourse about the existence of an atmosphere on the planet. The TRAPPIST-1 system, being a multi-planetary system susceptible to mean motion resonances, also serves as an interesting exemplar case to demonstrate these effects. Incorporating the stellar zenith angle to the geometrical analysis allows the possibility of physically feasible Bond albedo values that would otherwise be prohibited if a synchronously rotating bare rock scenario is assumed. Consequently, the degeneracies in the modelling of different atmospheric states of such planets can be reduced if the correct geometry is taken into account.

astro-ph.EP↗
arXiv2026

Update on the Orbital Motion of Encke's Periodic Comet: Nongravitational Deceleration Gradually Gaining

The end of an era in cometary astronomy --- as the transition from a nongravitational acceleration to a deceleration in the motion of Encke's comet was advertised in a paper of mine five years ago --- has now turned into a new era, as recent computations of the comet's nongravitational orbits performed independently by S. Nakano (CBAT) and by D. Farnocchia (JPL) appear to suggest. The new values of parameter A_2, compatible both with each other and with the earlier values in my previous paper, show that the magnitude of the deceleration has continued to grow. Critically assessed are the controversial computations at the Minor Planet Center, which contradict the above results and imply that Encke's comet was reverting to the acceleration. A plot of the number of observations used in the orbital solutions as a function of time shows an exponential rise following the introduction of CCD arrays, but not after use of photography became common five or six decades earlier. Dips in observer activity appear during the two World Wars. Because the comet has recently been observed along the entire orbit, the effective times that computed values of the nongravitational parameters apply to had to be redefined.

astro-ph.EP↗