Editing Molecular cloud (section)

===High-latitude diffuse molecular clouds===
{{main|Infrared cirrus}}

In 1984 [[IRAS]]{{clarify|which astronomers identified the "new type of diffuse molecular cloud" in circa 1984?  ...a science instrument, a telescope, cannot "identify" anything; it takes data, and comparisons, and decisions to identify something.|date=October 2021}} identified a new type of diffuse molecular cloud.<ref>{{cite journal | author=Low | title=Infrared cirrus – New components of the extended infrared emission | journal=Astrophysical Journal | date=1984| volume=278 | pages = L19 | doi = 10.1086/184213 | last2=Young | first2=E. | last3=Beintema | first3=D. A. | last4=Gautier | first4=T. N. | last5=Beichman | first5=C. A. | last6=Aumann | first6=H. H. | last7=Gillett | first7=F. C. | last8=Neugebauer | first8=G. | last9=Boggess | first9=N. | bibcode=1984ApJ...278L..19L | display-authors=1}}</ref> These were diffuse filamentary clouds that are visible at high [[Galactic coordinate system|galactic latitudes]]. These clouds have a typical density of 30 particles per cubic centimetre.<ref>{{cite journal | author=Gillmon, K. |author2=Shull, J.M. |name-list-style=amp | title= Molecular Hydrogen in Infrared Cirrus | journal=Astrophysical Journal | date=2006| volume=636 | pages= 908–915 | doi = 10.1086/498055 | bibcode=2006ApJ...636..908G|arxiv = astro-ph/0507587 | issue=2 |s2cid=18995587 }}</ref>[[File:Serpens_south.jpg|thumb|The [[Serpens South]] star cluster is embedded in a filamentary molecular cloud, seen as a dark ribbon passing vertically through the cluster. This cloud has served as a testbed for studies of molecular cloud stability.<ref name="FriesenBourke2016">{{cite journal|last1=Friesen|first1=R. K.|last2=Bourke|first2=T. L.|last3=Francesco|first3=J. Di|last4=Gutermuth|first4=R.|last5=Myers|first5=P. C.|title=The Fragmentation and Stability of Hierarchical Structure in Serpens South|journal=The Astrophysical Journal|volume=833|issue=2|year=2016|pages=204|issn=1538-4357|doi=10.3847/1538-4357/833/2/204|arxiv = 1610.10066 |bibcode = 2016ApJ...833..204F |s2cid=118594849 |doi-access=free }}</ref>]]