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Episodic accretion in protostars leads to luminosity outbursts that end up heating their surroundings. This rise in temperature pushes the snow lines back, enabling the desorption of chemical species from dust grain surfaces, which may…

Astrophysics of Galaxies · Physics 2024-07-17 P. Marchand , A. Coutens , J. Scigliuto , F. Cruz-Sáenz de Miera , A. Andreu , J. -C. Loison , Á. Kóspál , P. Ábrahám

We have performed observations of water maser emission towards a sample of low-mass protostars, in order to investigate the properties of jets associated with the earliest stages of star formation and their interaction with the surrounding…

Astrophysics of Galaxies · Physics 2015-05-13 J. -F. Desmurs , C. Codella , J. Santiago-Garcia , M. Tafalla , R. Bachiller

The Submillimeter Array has opened a new window to study the innermost warm and dense regions of the envelopes and disks around deeply embedded protostars. This paper presents high-angular resolution (< 2'') submillimeter observations of…

Recent observational studies of intermediate- and high-mass star-forming regions at submillimeter and infrared wavelengths are reviewed, and chemical diagnostics of the different physical components associated with young stellar objects are…

Astrophysics · Physics 2007-05-23 Ewine F. van Dishoeck , Floris F. S. van der Tak

Much attention has been placed on the dust distribution in protostellar envelopes, but there are still many unanswered questions regarding the structure of the gas. We aim to start identifying the factors that determine the chemical…

Evidence is mounting that the small bodies of our Solar System, such as comets and asteroids, have at least partially inherited their chemical composition from the first phases of the Solar System formation. It then appears that the…

The 12C/13C isotope ratio has been derived towards numerous cold clouds (20-50 K) and a couple protoplanetary disks and exoplanet atmospheres. However, direct measurements of this ratio in the warm gas (>100 K) around young low-mass…

The earliest stages of disk formation and dust evolution during the protostellar phase remain poorly constrained. Millimeter dust emission and its polarization provide key insights into the physical processes and material distribution at…

Solar and Stellar Astrophysics · Physics 2026-01-08 Asako Sato , Anaëlle Maury , Josep M. Girart , Andrea Bracco , Patrick Hennebelle , Qizhou Zhang , Valeska Valdivia

We assess the ionising effect of low energy protostellar cosmic rays in protoplanetary disks around a young solar mass star for a wide range of disk parameters. We assume a source of low energy cosmic rays located close to the young star…

Solar and Stellar Astrophysics · Physics 2020-01-08 D. Rodgers-Lee , A. M. Taylor , T. P. Downes , T. P. Ray

The oldest stars in the universe retain to a great extent detailed information on the chemical composition of the interstellar medium at the time of their birth. Hence the earliest phases of Galactic chemical evolution and nucleosynthesis…

Solar and Stellar Astrophysics · Physics 2013-01-31 Terese Hansen , Johannes Andersen , Birgitta Nordtröm

The formation and evolution of young low mass stars are characterized by important processes of mass loss and accretion ocurring in the innermost regions of their placentary circumstellar disks. Because of the large obscuration of these…

The embedded phase is a crucial period in the development of a young star. Mid-IR observations, now possible with JWST with unprecedented sensitivity, spectral resolution and sharpness are key for probing many physical and chemical…

Extremely large deuteration of several molecules has been observed towards prestellar cores and low-mass protostars for a decade. New observations performed towards low-mass protostars suggest that water presents a lower deuteration in the…

Astrophysics of Galaxies · Physics 2015-06-19 Vianney Taquet , Steven B. Charnley , Olli Sipilä

Protostellar outflows and jets are almost ubiquitous characteristics during the mass accretion phase, and encode the history of stellar accretion, complex-organic molecule (COM) formation, and planet formation. Episodic jets are likely…

(abridged) The nature of early Class 0/I protostellar discs is not clearly understood. Early protostellar discs are needed to drive molecular outflows and jets observed in star forming regions, but there has been some debate to how they…

Solar and Stellar Astrophysics · Physics 2012-03-08 Dennis F. Duffin , Ralph E. Pudritz , Daniel Seifried , Robi Banerjee , Ralf S. Klessen

The envelopes and disks that surround protostars reflect the initial conditions of star and planet formation and govern the assembly of stellar masses. Characterizing these structures requires observations that span the near-infrared to…

Solar and Stellar Astrophysics · Physics 2024-03-26 John J. Tobin , Patrick D. Sheehan

Understanding the formation mechanisms of protoplanetary disks and multiple systems, and their pristine properties, is a key question for modern astrophysics. The properties of the youngest disks, embedded in rotating infalling protostellar…

Context. Cosmic rays (CRs) play an important role in the chemistry and dynamics of the interstellar medium. In dense environments, they represent the main ionising agent, driving the rich chemistry of molecular ions and determining the…

Astrophysics of Galaxies · Physics 2021-12-11 Elena Redaelli , Olli Sipilä , Marco Padovani , Paola Caselli , Daniele Galli , Alexei V. Ivlev

Although, from a theoretical point of view, magnetic fields are believed to have a significant role during the early stages of star formation, especially during the main accretion phase, the magnetic field strength and topology is poorly…

We use archived IRAC images from the Spitzer Space Telescope to show that many Class 0 protostars exhibit complex, irregular, and non-axisymmetric structure within their dusty envelopes. Our 8 $\mu$m extinction maps probe some of the…

Solar and Stellar Astrophysics · Physics 2015-05-18 John J. Tobin , Lee Hartmann , Hsin-Fang Chiang , Leslie W. Looney
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