J/A+A/333/619 Upper Scorpius OB association Lithium survey (Preibisch+ 1998)
A lithium-survey for pre-main sequence stars in the upper
Scorpius OB association
Preibisch T., Guenther E., Zinnecker H., Sterzik M., Frink S., Roeser S.
<Astron. Astrophys. 333, 619 (1998)>
=1998A&A...333..619P 1998A&A...333..619P (SIMBAD/NED BibCode)
ADC_Keywords: Stars, pre-main sequence ; Equivalent widths ; Proper motions ;
Associations, stellar
Keywords: surveys - stars: kinematics - stars: pre-main sequence -
open clusters and associations: Scorpius Centaurus - X-rays: stars
Abstract:
We present the results of an intermediate resolution spectroscopic
survey for pre-main sequence (PMS) stars in the Upper Scorpius OB
association. In a 160 square-degree area we were able to identify 39
new PMS stars by follow up observations of X-ray selected stars with
the multi object spectrograph FLAIR at the UK Schmidt Telescope. We
also investigated the completeness of our X-ray selected sample by
observing more than 100 stars that were not detected as X-ray sources,
but have proper motions indicating membership to Upper Sco. While the
new X-ray selected PMS stars with known proper motions have kinematics
consistent with membership, none of the X-ray quiet proper motion
candidates is a PMS star. We conclude that our X-ray selected sample
of PMS stars seems to be rather complete. For stars in the magnitude
interval 11.5≲B≲13.5 we derive a conservative lower limit of 75%
completeness.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 79 78 Results for the X-ray selected PMS candidates
tablea2.dat 72 115 Results for the proper motion selected PMS candidates
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Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- GSC GSC (Cat. I/220) number
11 A1 --- Index See Note (1)
13- 14 I2 h RAh Right ascension (J2000)
16- 17 I2 min RAm Right ascension (J2000)
19- 22 F4.1 s RAs Right ascension (J2000)
25 A1 --- DE- Declination sign
26- 27 I2 deg DEd Declination (J2000)
29- 30 I2 arcmin DEm Declination (J2000)
32- 33 I2 arcsec DEs Declination (J2000)
36- 39 F4.1 mag Bmag B magnitude from GSC (Cat. I/220)
42- 46 F5.3 ct/s CR ROSAT count rate
49 A1 --- u_CR [:<] Uncertainty/upper limit note (2)
50- 53 F4.2 0.1nm W(Li) Li line equivalent width
54 A1 --- u_W(Li) [:<] Uncertainty/upper limit note (2)
56- 61 F6.2 0.1nm W(Ha) Hα line equivalent width
63- 64 A2 --- SpType Spectral type
65 A1 --- u_SpType Uncertainty flag on SpType
67- 69 A3 --- Type See Note (3)
71- 74 I4 mas/yr pmRA ? Proper motion in right ascension *cos(delta)
76- 78 I3 mas/yr pmDE ? Proper motion in declination
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Note (1): empty: X-ray source detected in the ROSAT All Sky Survey
P: X-ray source detected in pointed ROSAT observation only
Note (2): "<": Upper limit to the line width
":": Uncertainty exceeding 15%
Note (3): Classification of the objects
PMS: pre-main sequence star
YC: non-PMS star with a Lithium line as typical for stars in the
young clusters mentioned in Section 4
F: non-PMS star with a very weak lithium line
(probably active field star)
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Byte-by-byte Description of file: tablea2.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- GSC GSC (Cat. I/220) number
12- 13 I2 h RAh Right ascension (J2000)
15- 16 I2 min RAm Right ascension (J2000)
18- 21 F4.1 s RAs Right ascension (J2000)
24 A1 --- DE- Declination sign
25- 26 I2 deg DEd Declination (J2000)
28- 29 I2 arcmin DEm Declination (J2000)
31- 32 I2 arcsec DEs Declination (J2000)
36- 39 F4.1 mag Bmag B magnitude from GSC
42 A1 --- u_Bmag [:<] Uncertainty/upper limit note (1)
43- 46 F4.2 0.1nm W(Li) Li line equivalent width
47 A1 --- u_W(Li) [:<] Uncertainty/upper limit note (1)
50- 53 F4.2 0.1nm W(Ha) Hα line equivalent width
56- 57 A2 --- SpType Spectral type
58 A1 --- u_SpType Uncertainty flag on SpType
60- 61 A2 --- Type See Note (2)
64- 66 I3 mas/yr pmRA Proper motion in right ascension *cos(delta)
69- 71 I3 mas/yr pmDE Proper motion in declination
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Note (1): <": Upper limit to the line width
":": Uncertainty exceeding 15%
Note (2): Classification of the objects
YC: non-PMS star with a Lithium line as typical for stars in the
young clusters mentioned in Section 4
F: non-PMS star with a very weak lithium line
(probably active field star)
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Acknowledgements: Thomas Preibisch
(End) Patricia Bauer [CDS] 13-Feb-1998