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J/A+A/341/L79       Proper motions of faint ROSAT WTT stars   (Terranegra+ 1999)

Proper motions of faint ROSAT WTT stars in the Chamaeleon region. Terranegra L., Morale F., Spagna A., Massone G., Lattanzi M.G. <Astron. Astrophys. 341, L79 (1999)> =1999A&A...341..L79T (SIMBAD/NED BibCode)
ADC_Keywords: Proper motions ; Stars, late-type ; Radio sources Mission_Name: ROSAT Keywords: astrometry - stars: fundamental parameters - stars: kinematics - stars: late-type - stars: pre-main sequence Abstract: We present proper motions of 59 stars of the ROSAT All-Sky Survey (RASS) located in direction of the Chamaeleon star forming region (SFR) in the magnitude range B=5.1-17mag. Proper motions of the fainter stars were newly derived utilizing survey Schmidt plates from the GSC∼II plate archive and from a set of special plates taken with the ESO Schmidt telescope. The vector point diagram (VPD) indicates that the certified weak emission-line T Tauri (WTT) stars cluster away from the region occupied by the brighter pre-main-sequence stars (PMS) in Cha I. The distance to this new association is estimated at ∼100pc, sensibly smaller than the 150pc generally assumed for the SFR. This yields an upper limit of 2km/s for the velocity dispersion of this new kinematic group. The de-reddened CM diagram of the group members suggest the WTT stars are still PMS objects, but older (3-30Myr) and less massive than previous determinations. These revised age estimates, the newly derived group peculiar velocity, and current distance estimates to the Cha∼I/II/III complex would favour in-situ formation against that predicted by high velocity cloud models. Finally, based on a redetermination of the peculiar motions of stars and gas, we speculate that the whole SFR originated from the local Orion spur as a result of more classical mechanisms like interactions with the spiral arms. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 104 59 Proper motions for the 59 RASS stars 72 642 PostScript version of table1 table1.tex 144 122 LaTeX version of table1
See also: I/239 : The Hipparcos and Tycho Catalogues (ESA 1997) I/246 : The ACT Reference Catalog (Urban+ 1997) I/146 : Positions and Proper Motions - North (Roeser+, 1988) I/193 : Positions and Proper Motions - South (Bastian+ 1993) J/A+AS/114/109 : Cha X-ray sources + optical identifications (Alcala+ 1995) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 17 A17 --- Name ROSAT all-sky survey source designation Alcala' et al. (1995, Cat. J/A+AS/114/109) or catalogue designation 19- 20 A2 --- n_Name [* KG] Note on Name (1) 22- 33 A12 --- CatNo Astrometric catalog designation 35 A1 --- Cat [APHS] Catalogue name (2) 37- 42 F6.1 mas/yr pmRA Proper motion in right ascension (µRA*cosDE) 44- 46 F3.1 mas/yr e_pmRA ? rms uncertainty on pmRA 48- 52 F5.1 mas/yr pmDE Proper motion in declination 54- 56 F3.1 mas/yr e_pmDE ? rms uncertainty on pmDE 58- 62 F5.2 mas plx ? Parallax from Hipparcos catalogue (I/239) 64- 66 F3.1 mas e_plx ? rms uncertainty on plx 68- 69 A2 --- SpType Spectral Type 71- 74 F4.1 mag Vmag ? Stellar V magnitude 76- 80 A5 --- Type Stellar type (3) 82-104 A23 --- Names Other names
Note (1): *: The proper motion value for CED 110 is from Grasdalen G. (1977IAUCo..42...25G), while the values for SAO 256557 and RXJ1225.3-7857 are from the original catalogue and they are in the FK5 system. However the deviation from the Hipparcos system can be considered negligible in this work. KG: Stars belong to the kinematical group (see text). Note (2): A = ACT Catalog (Cat. I/246) P = PPM Catalog (Cat. I/146, I/193) H = Hipparcos Catalog (Cat. I/239) S = GSC S039 plate Note (3): PMS: Pre-Main Sequence stars from the high resolution spectroscopy by Covino et al. (1997A&A...328..187C) W: WTTS from low resolution spectroscopy by Alcala' et al. (1995, Cat. J/A+AS/114/109) UBS: uncorrelated bright stars by Alcala' et al. (1995, Cat. J/A+AS/114/109) CTTS: Classical T Tauri stars Ae/Be: Herbig Ae/Be stars
Acknowledgements: Luciano Terranegra
(End) Patricia Bauer [CDS] 08-Jan-1999
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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