Home     Getting Started     To Survive in the Universe    
Inhabited Sky
    News@Sky     Astro Photo     The Collection     Forum     Blog New!     FAQ     Press     Login  

HD 166052


Contents

Images

Upload your image

DSS Images   Other Images


Related articles

Cloud Fragmentation and Proplyd-like Features in H II Regions Imaged by the Hubble Space Telescope
We have analyzed Hubble Space Telescope ACS and WFPC2 new and archivalimages of eight H II regions to look for new protoplanetary disks(proplyds) similar to those found in the Orion Nebula. We find a wealthof features similar in size (although many are larger) to the brightcusps around the Orion Nebula proplyds. None of them, however, containsa definitive central star. From this, we deduce that the new cusps maynot be proplyds but instead fragments of molecular cloud material. Outof all the features found in the eight H II regions examined, only one,an apparent edge-on silhouette in M17, may have a central star. Thisfeature might join the small number of bona fide proplyds found outsidethe Orion Nebula, in M8, M20, and possibly M16. In line with the resultsfound recently by Smith et al., the paucity of proplyds outside theOrion Nebula can be explained by their transient nature, as well as bythe specific environmental conditions under which they can be observed.Several fragments are seen as dark silhouettes against a brightbackground. We have reanalyzed those found in IC 2944 by Reipurth et al.and found new, similar ones in M16. None of these fragments contains acentral star, and we exclude the possibility that they are disks.Reipurth et al. concluded that the IC 2944 silhouettes are not starforming. We argue here that their assumption of a constant optical depthfor these fragments is not physical and that it is more likely thatthese fragments are star forming, a condition that is supported,although not proved, by their shapes and distributions. The process ofcloud fragmentation and photoevaporation produces a large number ofsmall fragments, while the size hierarchy expected in a photoevaporativeenvironment would not favor small fragments. The size distributionsobserved will constrain any future theories of cloud fragmentation. Onebright microjet candidate is found in M17, protruding from a large,limb-brightened fragment. A second, larger, jetlike feature, similar inshape and size to a Herbig-Haro jet, is found in Pismis 24. No centralstar appears to be associated with either of these jet candidates.Based on observations made with the NASA/ESA Hubble Space Telescopeobtained at the Space Telescope Science Institute, which is operated bythe Association of Universities for Research in Astronomy (AURA), Inc.,under NASA contract NAS5-26555.

UBV RI Observations of Miscellaneous Stars
Not Available

Note on AX Sgr.
Abstract image available at:http://adsabs.harvard.edu/abs/1975AJ.....80..458F

Submit a new article


Related links

  • - No Links Found -
Submit a new link


Member of following groups:


Observation and Astrometry data

Constellation:いて座
Right ascension:18h09m44.44s
Declination:-18°50'39.9"
Apparent magnitude:7.652
Distance:286.533 parsecs
Proper motion RA:0.6
Proper motion Dec:-11.3
B-T magnitude:7.72
V-T magnitude:7.658

Catalogs and designations:
Proper Names   (Edit)
HD 1989HD 166052
TYCHO-2 2000TYC 6272-738-1
USNO-A2.0USNO-A2 0675-24288585
HIPHIP 88982

→ Request more catalogs and designations from VizieR