ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Meliaceae  (2)
  • Astronomy  (1)
  • 2005-2009  (3)
  • 2007  (3)
Collection
Years
  • 2005-2009  (3)
Year
  • 1
    Publication Date: 2019-08-26
    Description: The dust sublimation zone (DSZ) is the region of pre-main sequence (PMS) disks where dust grains most easily anneal, sublime, and condense out of the gas. Because of this, it is a location where crystalline material may be enhanced and redistributed throughout the rest of the disk. A decade-long program to monitor the thermal emission of the grains located in this region demonstrates that large changes in emitted flux occur in many systems. Changes in the thermal emission between 3 and 13.5 microns were observed in HD 31648 (MWC 480), HD 163296 (MWC 275), and DG Tau. This emission is consistent with it being produced at the DSZ, where the transition from a disk of gas to one of gas+dust occurs. In the case of DG Tau, the outbursts were accompanied by increased emission on the 10 micron silicate band on one occasion, while on another occasion it went into absorption. This requires lofting of the material above the disk into the line of sight. Such changes will affect the determination of the inner disk structure obtained through interferometry measurements, and this has been confirmed in the case of HD 163296. Cyclic variations in the heating of the DSZ will lead to the annealing of large grains, the sublimation of smaller grains, possibly followed by re-condensation as the zone enters a cooling phase. Lofting of dust above the disk plane, and outward acceleration by stellar winds and radiation pressure, can re-distribute the processed material to cooler regions of the disk, where cometesimals form. This processing is consistent with the detection of the preferential concentration of large crystalline grains in the inner few AU of PMS disks using interferometric spectroscopy with the VLTI.
    Keywords: Astronomy
    Type: 39th Annual DPS meeting; Oct 07, 2007 - Oct 12, 2007; Orlando, FL; United States
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    facet.materialart.
    Unknown
    In:  Blumea - Biodiversity, Evolution and Biogeography of Plants (0006-5196) vol.52 (2007) nr.1 p.179
    Publication Date: 2015-03-06
    Description: The African genus Heckeldora (Meliaceae) is revised. Contrary to earlier views the widespread and variable H. staudtii is shown to consist of four distinct entities, each worthy of specific status. Heckeldora zenkeri is therefore re-instated and two other species, originally described in the much larger genus Guarea, and formerly also considered conspecific with H. staudtii, are resurrected and formally transferred to Heckeldora. In addition, two new species, H. jongkindii J.J. de Wilde from Liberia and H. trifoliolata J.J. de Wilde from Gabon are recognized and described. Heckeldora mangenotiana is transferred to Guarea and the new combination made. A key to the six Heckeldora species now recognized is provided and maps of their distribution are presented.
    Keywords: Guarea ; Heckeldora ; Meliaceae ; Africa ; revision ; taxonomy
    Repository Name: National Museum of Natural History, Netherlands
    Type: Article / Letter to the editor
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    facet.materialart.
    Unknown
    In:  Blumea: Biodiversity, Evolution and Biogeography of Plants vol. 52 no. 1, pp. 179-199
    Publication Date: 2024-01-12
    Description: The African genus Heckeldora (Meliaceae) is revised. Contrary to earlier views the widespread and variable H. staudtii is shown to consist of four distinct entities, each worthy of specific status.\nHeckeldora zenkeri is therefore re-instated and two other species, originally described in the much larger genus Guarea, and formerly also considered conspecific with H. staudtii, are resurrected and formally transferred to Heckeldora. In addition, two new species, H. jongkindii J.J. de Wilde from Liberia and H. trifoliolata J.J. de Wilde from Gabon are recognized and described. Heckeldora mangenotiana is transferred to Guarea and the new combination made. A key to the six Heckeldora species now recognized is provided and maps of their distribution are presented.
    Keywords: Guarea ; Heckeldora ; Meliaceae ; Africa ; revision ; taxonomy
    Repository Name: National Museum of Natural History, Netherlands
    Type: info:eu-repo/semantics/article
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...