J/MNRAS/469/1783 33 T Tauri stars in Taurus Halpha measurements (Duchene+, 2017)
A search for passive protoplanetary discs in the Taurus-Auriga
star-forming region.
Duchene G., Becker A., Yang Y., Bouy H., De Rosa R.J., Patience J.,
Girard J.H.
<Mon. Not. R. Astron. Soc., 469, 1783-1808 (2017)>
=2017MNRAS.469.1783D 2017MNRAS.469.1783D (SIMBAD/NED BibCode)
ADC_Keywords: Stars, pre-main sequence ; Spectroscopy ; Equivalent widths
Keywords: circumstellar matter - stars: variables: T Tauri, Herbig Ae/Be
Abstract:
We conducted a 12-month monitoring campaign of 33 T Tauri stars (TTS)
in Taurus. Our goal was to monitor objects that possess a disc but
have a weak Hα line, a common accretion tracer for young stars,
in order to determine whether they host a passive circumstellar disc.
We used medium-resolution optical spectroscopy to assess the accretion
status of the objects and to measure the Hα line. We found no
convincing examples of passive discs: only transition disc and debris
disc systems in our sample are non-accreting. Among accretors, we
found no example of flickering accretion, leading to an upper limit of
2.2 per cent on the duty cycle of accretion gaps, assuming that all
accreting TTS experience such events. When combining literature
results with our observations, we found that the reliability of
traditional Hα-based criteria to test for accretion is high but
imperfect, particularly for low-mass TTS. We found a significant
correlation between stellar mass and the full width at 10 per cent of
the peak (W10) of the Hα line that does not seem to be
related to variations in free-fall velocity. Finally, our data
revealed a positive correlation between the Hα equivalent width
and its W10, indicative of a systematic modulation in the line
profile whereby the high-velocity wings of the line are proportionally
more enhanced than its core when the line luminosity increases. We
argue that this supports the hypothesis that the mass accretion rate
on the central star is correlated with the Hα W10 through a
common physical mechanism.
Description:
We conducted a 12-month monitoring campaign of a sample of 33 TTS in
the Taurus star-forming region, all but two of which host a
circumstellar disc.
The observations were gathered with the Calar Alto (CAHA) 3.5-m
telescope, the 4.2-m William Herschel Telescope (WHT), the San Pedro
Martir (SPM) 2.1-m telescope and the Lick Observatory Shane 3-m
telescope, using their respective optical spectrographs.
Data were obtained during nine separate nights in autumn 2009,
supplemented by a four-night run in autumn 2010 during which the most
interesting objects were observed in order to achieve a 1-yr
total-time baseline.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 67 33 Observed sample
table3.dat 160 313 Spectral line measurements
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See also:
J/A+A/312/439 : New T Tauri stars in Taurus-Auriga (Wichmann+, 1996)
J/A+AS/132/173 : New weak-line T Tauri stars in Taurus-Auriga (Li+, 1998)
J/A+A/519/A83 : T Tau stars toward the Taurus-Auriga region (Takita+, 2010)
J/ApJS/216/26 : GALEX search for T Tauri in Taurus-Auriga (Gomez+, 2015)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1 A1 --- Sample Sample (1)
3- 18 A16 --- Name Object name
22- 25 A4 --- SpType Spectral type (2)
26 A1 --- n_SpType [bd] Note on SpType (3)
28- 32 F5.2 mag Rmag ? R magnitude
34- 39 F6.1 0.1nm EWHa Hα equivalent width
41 I1 --- r_EWHa Reference for EWHa (4)
43 A1 --- TTS [CW] Litterature classification, TTS (5)
45- 46 A2 --- UV [YN? -] Litterature classification,
UV/veiling (6)
48- 54 A7 --- SED [II/III ] Spectral energy distribution (2)
55 A1 --- n_SED [ac] Note on SED (3)
57- 58 A2 --- Acc [Y/N? ] Accretor in this survey?
60 A1 --- Mult [SBTQ] multiplicity flag (7)
62- 63 I2 --- Nspec Number of spectra obtained in this study,
separated in time by a maximum of Dtmax
65- 67 I3 d Dtmax Separation time for Nspec
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Note (1): Sample as follows:
A = Candidate passive discs
B = Borderline objects
C = Control sample - Disc
D = Control sample - Disc-less
Note (2): Spectral types and spectral energy distribution (SED) class are
adopted from Herczeg & Hillenbrand (2014, Cat. J/ApJ/786/97) unless
otherwise stated.
Note (3): Individual notes as follows:
a = Far-infrared and mm excess (Andrews & Williams, 2005ApJ...631.1134A 2005ApJ...631.1134A;
Howard et al. 2013ApJ...767..112I 2013ApJ...767..112I)
b = Wichmann et al. (1996, Cat. J/A+A/312/439)
c = 24um and 70um excess (Wahhaj et al., 2010, Cat. J/ApJ/724/835;
Cieza et al., 2013ApJ...762..100C 2013ApJ...762..100C)
d = Luhman et al. (2010, Cat. J/ApJS/186/111)
Note (4): References for Halpha measurements as follows:
1 = Herbig & Bell (1988LicOB1111....1H 1988LicOB1111....1H, Cat. V/73)
2 = White & Ghez (2001ApJ...556..265W 2001ApJ...556..265W)
3 = Wahhaj et al. (2010, Cat. J/ApJ/724/835)
4 = Strom & Strom (1994ApJ...424..237S 1994ApJ...424..237S)
5 = Beckwith et al. (1990AJ.....99..924B 1990AJ.....99..924B)
6 = Briceno et al. (1998AJ....115.2074B 1998AJ....115.2074B)
7 = Hartigan, Strom & Strom (1994ApJ...427..961H 1994ApJ...427..961H)
8 = Nguyen et al. (2009ApJ...694L.153N 2009ApJ...694L.153N)
Note (5): The literature TTS classification is based on the strength of the
Hα line relative to the spectral-type-dependent accretion threshold
defined by Barrado y Navascues & Martin (2003AJ....126.2997B 2003AJ....126.2997B).
Note (6): The presence of UV excess and/or optical veiling is assessed from the
work of Valenti et al. (1993AJ....106.2024V 1993AJ....106.2024V);
Muzerolle et al. (1998AJ....116.2965M 1998AJ....116.2965M); White & Ghez (2001ApJ...556..265W 2001ApJ...556..265W);
White & Basri (2003ApJ...582.1109W 2003ApJ...582.1109W);
Valenti et al. (2003, Cat. J/ApJS/147/305);
Herczeg & Hillenbrand (2008ApJ...681..594H 2008ApJ...681..594H, 2014, Cat. J/ApJ/786/97) and
Ingleby et al. (2013ApJ...767..112I 2013ApJ...767..112I).
Note (7): Multiplicity flag as follows:
S = single system
B = binary system
T = triple system
Q = quadruple system
only companions out to projected separations up to 2000au are considered.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- Name Target name
18- 28 A11 "date" Date Observation date
29 A1 --- Note [W] W for Weighted average (1)
31- 33 I3 --- SNR ? Signal-to-noise ratio estimated in the
6400-6700Å range, reported on a per
resolution element basis
35- 39 F5.1 0.1nm EWHa Hα equivalent width
41- 44 F4.1 0.1nm E_EWHa Error on Ha equivalent width (upper value)
46- 49 F4.1 0.1nm e_EWHa Error on Ha equivalent width (loper value)
51 A1 --- l_W10 [<≥ ] Limit flag on W10
52- 54 I3 km/s W10 ? Hα full width at 10% of the flux
56- 58 I3 km/s E_W10 ? Error on W10 (upper value)
60- 62 I3 km/s e_W10 ? Error on W10 (lower value)
64 A1 --- Asym [YN-] Asymetric profile
66- 67 A2 --- l_EWHeI5876 [<≥ ] Limit flag on EWHeI5876
68- 72 F5.2 0.1nm EWHeI5876 ? HeI 5876 equivalent width
74- 77 F4.2 0.1nm e_EWHeI5876 ? HeI 5876 equivalent width error
79- 80 A2 --- l_EW[OI] [<≥ ] Limit flag on EW[OI]
81- 85 F5.2 0.1nm EW[OI] ? [OI]6300 equivalent width
87- 90 F4.2 0.1nm e_EW[OI] ? [OI]6300 equivalent width error
92- 93 A2 --- l_EWHeI6678 [<≥ ] Limit flag on EWHeI6678
94- 98 F5.2 0.1nm EWHeI6678 ? HeI 6678 equivalent width
100-103 F4.2 0.1nm e_EWHeI6678 ? HeI 6678 equivalent width error
105-106 A2 --- l_EWCa8498 [<≥ ] Limit flag on EWCa8498
107-112 F6.2 0.1nm EWCa8498 ? Ca 8498 equivalent width
114-117 F4.2 0.1nm e_EWCa8498 ? Ca 8498 equivalent width error
119-120 A2 --- l_EWCa8542 [<≥ ] Limit flag on EWCa8542
121-126 F6.2 0.1nm EWCa8542 ? Ca 8542 equivalent width
128-131 F4.2 0.1nm e_EWCa8542 ? Ca 8542 equivalent width error
133-134 A2 --- l_EWCa8862 [<≥ ] Limit flag on EWCa8862
135-140 F6.2 0.1nm EWCa8862 ? Ca 8862 equivalent width
142-145 F4.2 0.1nm e_EWCa8862 ? Ca 8862 equivalent width error
147-148 A2 --- l_EWLi [<≥ ] Limit flag on EWLi
149-152 F4.2 0.1nm EWLi ? Li 6707 equivalent width
154-157 F4.2 0.1nm e_EWLi ? Li 6707 equivalent width error
159-160 A2 --- Acc [YN? -] Accretor status ? (see Section 4.5)
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Note (1): The last line for each object provides the average and standard
deviation of all Hα EW and W10 measurements (or the median upper limit
on W10 in the case of objects for which most spectra did not yield a
detection), as well as the average and standard deviation of the mean for all
detections of the Li 6707 absorption line.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 02-Apr-2020