Pronura bidoup n. sp. (Collembola, Neanuridae, Neanurinae, Paleonurini) from southern Vietnam

A new species of Pronura Delamare Debouteville, 1953, Pronura bidoup n. sp. is described from the Bi Doup massif in southern Vietnam, where it is largely distributed above 1,350 m. The new species exhibits a combination of characters unusual for the genus: shift of chaeta f towards chaeta e on labium, large central reticulate plate on head, presence of microchaetae on furcal rest, reduced chaetotaxy of legs and abdominal segment VI. It is related to Pronura ornata Deharveng & Bedos, 1993 from high altitude in Thailand

Triggered massive-star formation on the borders of Galactic HII regions. IV- Star formation at the periphery of Sh2-212

Aims: We wish to establish whether sequential star formation is taking place at the periphery of the Galactic HII region Sh2-212. Methods: We present CO millimetre observations of this region obtained at the IRAM 30-m telescope to investigate the distribution of associated molecular material. We also use deep JHK observations obtained at the CFHT to study the stellar content of the region, and radio observations obtained at the VLA to look for the presence of an ultra-compact (UC) HII region and for maser emission. Results: In the optical, Sh2-212 is spherically symmetric around its central exciting cluster. This HII region is located along a molecular filament. A thin, well-defined half ring of molecular material surrounds the brightest part of the HII region at the rear and is fragmented. The most massive fragment (~200 solar masses) contains a massive young stellar object displaying a near-IR excess; its spectral energy distribution indicates a high-mass (~14solar masses), high-temperature (~30000K), and high-luminosity (~17000 solar luminosities) source. This object ionizes a UC HII region. Conclusions: Sh2-212 is a good example of massive-star formation triggered via the collect and collapse process. The massive YSO observed at its periphery is a good candidate for a massive star formed in isolation.Comment: 12 pages, 14 figures. To be published in A&

Pronura bidoup sp. n. (Collembola, Neanuridae, Neanurinae, Paleonurini) del sur de Vietnam

A new species of Pronura Delamare Debouteville, 1953, Pronura bidoup n. sp. is described from the Bi Doup massif in southern Vietnam, where it is largely distributed above 1,350 m. The new species exhibits a combination of characters unusual for the genus: shift of chaeta f towards chaeta e on labium, large central reticulate plate on head, presence of microchaetae on furcal rest, reduced chaetotaxy of legs and abdominal segment VI. It is related to Pronura ornata Deharveng & Bedos, 1993 from high altitude in Thailand.Se describe una nueva especie de Pronura Delamare Debouteville, 1953, Pronura bidoup sp. n., del macizo Bi Doup, situado en el sur de Vietnam, donde se distribuye ampliamente por encima de los 1.350 m de altitud. Esta nueva especie presenta una serie de caracteres poco usuales para el género: desplazamiento de la queta f hacia la queta e en el labium, placa central grande reticulada en la cabeza, presencia de microquetas en la base de la furca, quetotaxia reducida en las patas y en el segmento abdominal VI. P. bidoup sp. n. está relacionada con P. ornata Deharveng y Bedos, 1993, que se encuentra a gran altitud en Tailandia

Folsomia abrupta n. sp. (Collembola, lsotomidae) from southern Vietnam

A new lsotomid Collernbola, Folsomia abrupta n. sp., is described from the Bi Doup massif in southern Vietnam, where it frequently occurs in rnedium to high altitude forest soils. Together with F: minipunctata Zhao & Tamura, 1992 from China, it constitutes a well-defined species group restricted to Sou~heasAt sia. Key woras: Collembola, Isotomidae, Folsomia abrupta n. sp., New species, Vietnam.A new lsotomid Collernbola, Folsomia abrupta n. sp., is described from the Bi Doup massif in southern Vietnam, where it frequently occurs in rnedium to high altitude forest soils. Together with F: minipunctata Zhao & Tamura, 1992 from China, it constitutes a well-defined species group restricted to Sou~heasAt sia. Key woras: Collembola, Isotomidae, Folsomia abrupta n. sp., New species, Vietnam.A new lsotomid Collernbola, Folsomia abrupta n. sp., is described from the Bi Doup massif in southern Vietnam, where it frequently occurs in rnedium to high altitude forest soils. Together with F: minipunctata Zhao & Tamura, 1992 from China, it constitutes a well-defined species group restricted to Sou~heasAt sia. Key woras: Collembola, Isotomidae, Folsomia abrupta n. sp., New species, Vietnam

Triggered massive-star formation on the borders of Galactic HII regions. III. Star formation at the periphery of Sh2-219

Context. Massive-star formation triggered by the expansion of HII regions. Aims. To understand if sequential star formation is taking place at the periphery of the HII region Sh2-219. Methods. We present 12CO(2-1) line observations of this region, obtained at the IRAM 30-m telescope (Pico Veleta, Spain). Results. In the optical, Sh2-219 is spherically symmetric around its exciting star; furthermore it is surrounded along three quarters of its periphery by a ring of atomic hydrogen. This spherical symmetry breaks down at infrared and millimetre wavelengths. A molecular cloud of about 2000\msol lies at the southwestern border of Sh2-219, in the HI gap. Two molecular condensations, elongated along the ionization front, probably result from the interaction between the expanding HII region and the molecular cloud. In this region of interaction there lies a cluster containing many highly reddened stars, as well as a massive star exciting an ultracompact HII region. More surprisingly, the brightest parts of the molecular cloud form a `chimney', perpendicular to the ionization front. This chimney is closed at its south-west extremity by H-alpha walls, thus forming a cavity. The whole structure is 7.5 pc long. A luminous H-alpha emission-line star, lying at one end of the chimney near the ionization front, may be responsible for this structure. Confrontation of the observations with models of HII region evolution shows that Sh2-219 is probably 10^5 yr old. The age and origin of the near-IR cluster observed on the border of Sh2-219 remain unknown.Comment: 11 pages, 10 figures. To be published in A&

Triggered massive-star formation on the borders of Galactic HII regions. II. Evidence for the collect and collapse process around RCW 79

We present SEST-SIMBA 1.2-mm continuum maps and ESO-NTT SOFI JHK images of the Galactic HII region RCW 79. The millimetre continuum data reveal the presence of massive fragments located in a dust emission ring surrounding the ionized gas. The two most massive fragments are diametrically opposite each other in the ring. The near-IR data, centred on the compact HII region located at the south-eastern border of RCW 79, show the presence of an IR-bright cluster containing massive stars along with young stellar objects with near-IR excesses. A bright near- and mid-IR source is detected towards maser emissions, 1.2 pc north-east of the compact HII region centre. Additional information, extracted from the Spitzer GLIMPSE survey, are used to discuss the nature of the bright IR sources observed towards RCW 79. Twelve luminous Class I sources are identified towards the most massive millimetre fragments. All these facts strongly indicate that the massive-star formation observed at the border of the HII region RCW 79 has been triggered by its expansion, most probably by the collect and collapse process.Comment: 14 pages, 15 figures. Accepted for publication in A&A. The images have been highly compressed for astro-ph. A version of this paper with higher-resolution figures is available at http://www.oamp.fr/matiere/rcw79.pd

Star Formation Towards The Galactic H Ii Region Rcw 120 - Herschel Observations Of Compact Sources

The expansion of H ii regions can trigger the formation of stars. An overdensity of young stellar objects is observed at the edges of H ii regions but the mechanisms that give rise to this phenomenon are not clearly identified. Moreover, it is difficult to establish a causal link between H ii -region expansion and the star formation observed at the edges of these regions. A clear age gradient observed in the spatial distribution of young sources in the surrounding might be a strong argument in favor of triggering