J/ApJ/658/480 Pre-main-sequence stars in Lupus association (Makarov+, 2007)
The Lupus association of pre-main-sequence stars: clues to star formation
scattered in space and time.
Makarov V.V.
<Astrophys. J., 658, 480-486 (2007)>
=2007ApJ...658..480M 2007ApJ...658..480M
ADC_Keywords: Associations, stellar ; Stars, pre-main sequence ;
Proper motions ; Photometry, UBVRI ; Photometry, infrared
Keywords: open clusters and associations: individual (Lupus) -
stars: distances - stars: formation - stars: kinematics -
stars: pre-main sequence
Abstract:
Kinematical analysis of spectroscopically identified pre-main-sequence
stars associated with the Lupus dark cloud reveals a streamlike motion
of low internal velocity dispersion (≤1.3km/s). A statistically
significant mismatch between the convergent point radial velocity and
the spectroscopic radial velocity from the literature indicates a
moderate degree of expansion. The rate of expansion is too low to
account for the present extent of the association if one assumes that
the spatially dispersed population was formed in the dense molecular
cores observed today. Therefore, it is unlikely that the outlying
weak-lined T Tauri members were born in the same star-forming cores as
the more compactly located classical T Tauri stars, despite the
kinematic integrity of the association. Distances inferred from the
classical moving-cluster method show a large depth of the association
(∼80pc) along the line of sight. A color-magnitude diagram of the
association in the near-IR colors corrected for the distribution of
distances shows a clear gap separating the older (5-27Myr) and the
younger (∼1Myr) generations of stars. Half of the identified 1Myr
old stars lie in the tight group of mostly classical T Tauri stars
associated with the Lupus 3 dark filament. This nest of very young
stars appears to be 25pc farther from the Sun than the center of the
greater Lupus association.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 121 93 Kinematic T Tauri Members of the Lupus Association
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See also:
J/A+A/320/185 : UBVRIcJHKL photometry in Lup (Wichmann+ 1997)
J/A+A/326/211 : T Tau Stars (Wichmann+, 1997)
J/A+AS/123/329 : New weak-line T Tauri stars in Lupus (Krautter+ 1997)
J/MNRAS/331/474 : ubvyβ photometry in the Lupus dark cloud (Franco, 2002)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- Name Star name
15 A1 --- n_Name [y] Very young object (1)
17- 27 F11.7 deg RAdeg Right ascension in decimal degrees (J2000)
29- 39 F11.7 deg DEdeg Declination in decimal degrees (J2000)
41- 45 F5.1 mas/yr pmRA Proper motion along RA, pmRA*cosDE
47- 51 F5.1 mas/yr pmDE Proper motion along DE
53- 55 F3.1 mas/yr e_pmRA rms uncertainty on pmRA
57- 59 F3.1 mas/yr e_pmDE rms uncertainty on pmDE
61- 63 I3 pc Dkin Kinematic distance
65- 68 F4.1 --- Dev Relative angular deviation,
Δ/σΔ
70- 73 F4.1 km/s Vtan Transverse tangential velocity component
75- 79 F5.2 mag Vmag ?=- V magnitude
81- 84 F4.2 mag B-V ?=- B-V colour index
86- 90 F5.2 mag U-B ?=- U-B colour index
92- 95 F4.2 mag V-Rc ?=- V-Rc colour index
97-100 F4.2 mag V-Ic ?=- V-Ic colour index
102-107 F6.3 mag Jmag J magnitude
109-114 F6.3 mag Hmag H magnitude
116-121 F6.3 mag Ksmag Ks magnitude
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Note (1): 'y' indicate stars whose location on the near-infrared H-R
diagram suggests they may be as young as 1Myr
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History:
* 20-Feb-2009: From electronic version of the journal
* 11-Jun-2009: Typos detected in line 35 to 54. Lines corrected by author
(End) Patricia Vannier [CDS] 21-Jan-2009