J/A+A/312/439 New T Tauri stars in Taurus-Auriga (Wichmann+, 1996)
New weak-line T Tauri stars in Taurus-Auriga
Wichmann R., Krautter J., Schmitt J.H.M.M., Neuhauser R., Alcala J.M.,
Zinnecker H., Wagner R.M., Mundt R., Sterzik M.F.
<Astron. Astrophys. 312, 439 (1996)>
=1996A&A...312..439W 1996A&A...312..439W (SIMBAD/NED BibCode)
ADC_Keywords: Stars, pre-main sequence; X-ray sources
Mission_Name: ROSAT
Keywords: stars: formation - stars: late-type - stars: pre-main sequence -
X-rays: stars - surveys
Abstract:
On the basis of the ROSAT All-Sky-Survey, a study of the Taurus-Auriga
star forming region has been performed in order to search for hitherto
undiscovered T Tauri stars. Our study covers an area of about 280
square degrees, located between 4h and 5h in right ascension and
between 15deg and 34deg in declination. Identification of ROSAT
All-Sky Survey sources in this area by means of optical spectroscopy
revealed 2 new classical T Tauri stars (CTTS) and 66 new weak-line-T
Tauri stars (WTTS) with Wλ(Hα)≤10A. Additional pointed
ROSAT observations led to the identification of 6 more WTTS and 2
CTTS, giving a total of 76 new T Tauri stars. The large area of our
study, as compared with previous works, allows us to study the spatial
distribution of WTTS in this star forming region. We find the WTTS of
our survey to be distributed over the whole region investigated. There
is a noticeable decline of the surface density from south to north
within our study area, but the spatial distribution extends most
probably beyond our study region. No clustering towards the population
of T Tauri stars known prior to ROSAT in Taurus-Auriga could be
observed. We suggest that the WTTS found in our study might in part be
somewhat older than the previously known T Tauri stars in
Taurus-Auriga, and that their broad spatial distribution is due to the
typical velocity dispersion of a few km/s measured for Taurus T Tauri
stars, in which case for some of our WTTS an age on the order of
107years would be required for reaching the observed distances from
the Taurus dark clouds. We estimate a WTTS/CTTS ratio of about 6
within our study area, but conclude that because of the different
spatial distribution of WTTS and CTTS this ratio will be most probably
significantly larger for a more extended area.
File Summary:
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File Name Lrecl Records Explanations
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ReadMe 80 . This file
table4 75 76 New T Tauri stars in Taurus-Auriga
table5 73 47 Non-TTS emission-line stars found in the
course of our survey
table6 111 71 ROSAT X-ray data and spectral fit results for
new T Tauri stars
table7 79 92 X-ray sources in pointed observations
tables.tex 107 668 LaTeX version of tables
figure5a.ps 69 4041 Low-dispersion spectral atlas of new WTTS in
Taurus-Auriga. Shown is the H_alpha and Li I
region.
figure5b.ps 69 3891 Figure5 cont.
figure5c.ps 69 4086 Figure5 cont.
figure5d.ps 69 4021 Figure5 cont.
figure5e.ps 69 4032 Figure5 cont.
figure5f.ps 69 3968 Figure5 cont.
figure5g.ps 69 4086 Figure5 cont.
figure5h.ps 69 2412 Figure5 cont.
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See also:
J/A+A/297/391 : T Tauri stars ROSAT survey (Neuhaeuser+, 1995)
J/A+AS/132/173 : New weak-line T Tauri stars in Taurus-Auriga (Li+ 1998)
Byte-by-byte Description of file: table4
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Bytes Format Units Label Explanations
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1- 3 I3 --- No Number
5- 19 A15 --- Name Identifier of star (1)
21 A1 --- n_Pos [X] Note on position (2)
23 A1 --- n_Xray [P] Note on X-ray detection (3)
26- 27 I2 h RAh Right Ascension for equinox J2000.0
29- 30 I2 min RAm Right Ascension for equinox J2000.0
32- 36 F5.2 s RAs Right Ascension for equinox J2000.0
38 A1 --- DE- Declination sign
39- 40 I2 deg DEd Declination for equinox J2000.0
42- 43 I2 arcmin DEm Declination for equinox J2000.0
45- 48 F4.1 arcsec DEs Declination for equinox J2000.0
53- 57 F5.1 0.1nm EW(Ha) Equivalent width for H_alpha
60- 65 A6 --- Sp Spectral type
68- 71 F4.1 mag Pmag Magnitude as listed in the Hubble GSC (4)
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Note (1): HD 285751: this star has independently been detected as T Tauri star
by F.M. Walter (1994, private communication); X-ray data are
also given in Neuhauser et al. (1995A&A...297..391N 1995A&A...297..391N)
RXJ0458.7+2046 discovered on the basis of preliminary RASS data, but
not detected in EXSAS reduction, therefore in table5 for
this star no X-ray data are given
Note (2): X : Position is X-ray position, star is not included in
Hubble GSC
blank : Position is taken from Hubble GSC
Note (3): P : Star was discovered by pointed observations
blank : Star was discovered by the ROSAT All-Sky Survey
Note (4): For stars not listed in the Hubble GSC a magnitude of 0.0 is given
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Byte-by-byte Description of file: table5
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Bytes Format Units Label Explanations
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1- 15 A15 --- Name Identifier of star
17 A1 --- n_Pos [X] Note on position (1)
19 A1 --- n_Xray [P] Note on X-ray detection (2)
21- 22 I2 h RAh Right Ascension for equinox J2000.0
24- 25 I2 min RAm Right Ascension for equinox J2000.0
27- 30 F4.1 s RAs Right Ascension for equinox J2000.0
33 A1 --- DE- Declination sign
34- 35 I2 deg DEd Declination for equinox J2000.0
37- 38 I2 arcmin DEm Declination for equinox J2000.0
40- 43 F4.1 arcsec DEs Declination for equinox J2000.0
46- 50 F5.3 s-1 CR Background subtracted X-ray count rate
(0.1-2.4keV energy range)
54- 58 F5.3 s-1 e_CR Error in CR
62- 66 A5 --- Sp Spectral type
68- 72 F5.1 0.1nm EW(Ha) Equivalent width for H_alpha
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Note (1): X : Position is X-ray position, star is not included in
Hubble GSC
blank : Position is taken from Hubble GSC
Note (2): P : Star was discovered by pointed observations
blank : Star was discovered by the ROSAT All-Sky Survey
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Byte-by-byte Description of file: table6
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Bytes Format Units Label Explanations
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1- 14 A14 --- Name Identifier of star
16 A1 --- n_Pos [P] Note on X-ray data (1)
18- 22 F5.1 --- ML Maximum likelihood of existence
25- 29 F5.1 --- Cts Background subtracted X-ray counts
(0.1 to 2.4 keV energy range)
32- 35 F4.1 --- e_Cts Errors for X-ray counts
37- 42 F6.1 s Exp Exposure time
44- 48 F5.2 --- HR1 Hardness ratio 1
50- 53 F4.2 --- e_HR1 Error in hardness ratio 1
55- 59 F5.2 --- HR2 Hardness ratio 2
61- 64 F4.2 --- e_HR2 Error in hardness ratio 2
66- 70 F5.2 [cm-2] log(NH) Logarithm of HI column density (2)
72- 75 F4.2 [cm-2] E_log(NH) Positive error for log(NH)
77- 80 F4.2 [cm-2] e_log(NH) Negative error for log(NH)
82- 85 F4.2 keV TX Temperature (2)
87- 90 F4.2 keV E_TX Positive error for TX
92- 95 F4.2 keV e_TX Negative error for TX
97-100 F4.2 10+23W LX X-ray luminosity (1030erg/s) (3)
102-105 F4.2 10+23W E_LX Positive error for LX
107-110 F4.2 10+23W e_LX Negative error for LX
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Note (1): P : X-ray data are from pointed observations
blank : X-ray data are from the ROSAT All-Sky Survey
Note (2): NH and TX are free parameters for the fits of the X-ray spectra
Note (3): For the calculation of LX a distance of 140pc has been assumed
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Byte-by-byte Description of file: table7
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Bytes Format Units Label Explanations
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1- 16 A16 --- Name Identifier of star
18- 19 I2 h RAh Right Ascension for equinox J2000.0
21- 22 I2 min RAm Right Ascension for equinox J2000.0
24- 28 F5.2 s RAs Right Ascension for equinox J2000.0
32 A1 --- DE- Declination sign
33- 34 I2 deg DEd Declination for equinox J2000.0
36- 37 I2 arcmin DEm Declination for equinox J2000.0
39- 42 F4.1 arcsec DEs Declination for equinox J2000.0
45- 49 F5.3 s-1 Cts Background subtracted X-ray count rate
(0.1-2.4 keV energy range)
51- 55 F5.3 s-1 e_Cts Error in X-ray count rate
57- 61 F5.2 --- HR1 Hardness Ratio 1
63- 66 F4.2 --- e_HR1 Error in Hardness Ratio 1
68- 72 F5.2 --- HR2 Hardness Ratio 2
74- 77 F4.2 --- e_HR2 Error in Hardness Ratio 2
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References:
Neuhauser R., Sterzik M.F., Schmitt J.H.M.M., Wichmann R.,
Krautter J. 1995b, =1995A&A...297..391N 1995A&A...297..391N
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Courtesy: Rainer Wichmann
(End) Patricia Bauer [CDS] 10-Apr-1996