It has since been identified as the prototypical cometary nebula, a class of fan-shaped reflection nebulae that are often associated with T Tauri stars (very young, variable, low-mass stars often in binary systems; some have circumstellar
disks and are likely progenitors of planetary systems).
There are models involving circumstellar
material - like exocomets, which were Boyajian's team's original hypothesis - which seem to be consistent with the data we have.
111) The composition, molecular abundances (112), and physical characteristics of the ISM such as temperature, density, and the intensity and type of electromagnetic and cosmic radiation of interstellar, circumstellar
, and protostellar clouds have provided additional insight into the constraints and possibilities for the creation or destruction of advanced organic chemistry.
Among specific topics are dynamics of wind and variations of circumstellar
extinction in the accreting T.
ALMA and VLT/SPHERE recently released spectacular images of circumstellar
disks around young stars, which exhibit large-scale structures ( 10 AU), including rings, gaps, and spiral arms that presumably are the signposts of planet formation.
50 Newmarket A circumstellar
disc in the solar system beyond the planets, extending from the orbit of Neptune to approximately 50 astronomical units from the sun.
As with discussions of circumstellar
habitable zones, some simplifying assumptions are helpful.
Before finding itself on the star, however, most of the cloud lands onto a circumstellar
disk forming around the star owing to conservation of angular momentum.
By directly imaging young planetary-mass objects and circumstellar
structures situated at relatively large distances from the central stars, we will address the current key issues for understanding planet formation.
Equivalent width, the area of the spectral peak with respect to the continuum, describes the strength of the hydrogen line which allowed us to theoretically track the changes in the amount of ionized hydrogen within the circumstellar
3-cm wavelengths and is used for observations of interstellar and circumstellar
molecules, pulsars, quasars and active galaxies.
7 GHz methanol masers are an exclusive tracer of an early stage of massive star formation but their exact location in the circumstellar
environment is still a matter of much debate.