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J/AJ/133/1795       Globulettes in four HII regions          (Gahm+, 2007)

Globulettes as seeds of brown dwarfs and free-floating planetary-mass objects. Gahm G.F., Grenman T., Fredriksson S., Kristen H. <Astron. J., 133, 1795-1809 (2007)> =2007AJ....133.1795G
ADC_Keywords: H II regions ; Globules ; Morphology Keywords: H II regions - ISM: general - ISM: globules - planets and satellites: general - stars: formation Abstract: Some HII regions surrounding young stellar clusters contain tiny dusty clouds, which on photos look like dark spots or teardrops against a background of nebular emission. From our collection of Hα images of 10 HII regions gathered at the Nordic Optical Telescope, we found 173 such clouds, which we call "globulettes", since they are much smaller than normal globules and form a distinct class of objects. Many globulettes are quite isolated and located far from the molecular shells and elephant trunks associated with the regions. Others are attached to the trunks (or shells), suggesting that globulettes may form as a consequence of erosion of these larger structures. None of our objects appear to contain stellar objects. The globulettes were measured for position, dimension, and orientation, and we find that most objects are smaller than 10kAU. Description: Deep narrowband Hα images of 50 total fields in 10 HII regions were collected with the 2.6m Nordic Optical Telescope on La Palma, Canary Islands, Spain. Two different filters were used: in 1999 a narrowband filter with 33Å FWHM, covering the nebular emission from only the Hα line, and in 2000 a filter with 180Å FWHM, also including the strong nebular emission lines of [NII] at 6548.1 and 6583.6Å, flanking the Hα line, and hence including more nebular emission. Objects: ---------------------------------------------------------- RA (2000) DE Designation(s) ---------------------------------------------------------- 02 32 42 +61 27 IC 1805 = Cl Melotte 15 19 42 27.9 +23 05 15 NGC 6820 = IRAS 19403+2258 00 03 06 +67 23 NGC 7822 = CTB 2 06 31 40 +04 57 48 Rosette Nebula = CTB 21 ---------------------------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 84 173 List of globulettes with central positions, dimensions, position angle, mean mass and density
Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 14 A14 --- Name HII region identification 16- 18 I3 --- Glob Globulette identification number (1) 20- 23 A4 --- n_Glob Morphological note on Glob (2) 25- 26 I2 h RAh Hour of Right Ascension (J2000) 28- 29 I2 min RAm Minute of Right Ascension (J2000) 31- 35 F5.2 s RAs Second of Right Ascension (J2000) 37 A1 --- DE- Sign of the Declination (J2000) 38- 39 I2 deg DEd Degree of Declination (J2000) 41- 42 I2 arcmin DEm Arcminute of Declination (J2000) 44- 47 F4.1 arcsec DEs Arcsecond of Declination (J2000) 49- 52 F4.1 arcsec MajAxis Semi-major axis 54- 57 F4.1 arcsec MinAxis Semi-minor axis 59- 63 F5.2 kAU Rad Characteristic radius (mean of the semi-axes) 65- 69 F5.1 deg PA [-90/90]? Position angle of elongated objects 71 A1 --- f_PA [*] when PA not well defined (round object) 73- 78 F6.2 jovMass Mass Mean mass in Jupiter masses 80- 84 F5.2 10-20g/cm3 rho Density
Note (1): Objects identified as [GGF2007] "Name" NNN, where "Name" is the HII region name Note (2): The following notations are used: BR = bright rim or halo T = pronounced tail F = distinct filamentary connection to larger cloud structures
History: From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 03-May-2009
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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