J/ApJ/935/54 LDT UBVRI photometry of 14 T-Tauri (Robinson+, 2022)
Understanding Accretion Variability through TESS Observations of Taurus.
Robinson C.E., Espaillat C.C., Rodriguez J.E.
<Astrophys. J., 935, 54 (2022)>
=2022ApJ...935...54R 2022ApJ...935...54R
ADC_Keywords: YSOs; Stars, masses ; Photometry, UBVRI
Keywords: Protoplanetary disks ; Stellar accretion
Abstract:
Interpreting the short-timescale variability of the accreting, young,
low-mass stars known as Classical T-Tauri stars remains an open task.
Month-long, continuous light curves from the Transiting Exoplanet
Survey Satellite (TESS) have become available for hundreds of T-Tauri
stars. With this vast data set, identifying connections between the
variability observed by TESS and short-timescale accretion variability
is valuable for characterizing the accretion process. To this end, we
obtained short-cadence TESS observations of 14 T-Tauri stars in the
Taurus star formation region along with simultaneous ground-based,
UBVRI-band photometry to be used as accretion diagnostics. In
addition, we combine our data set with previously published
simultaneous near- UV-near-IR Hubble Space Telescope spectra for one
member of the sample. We find evidence that much of the
short-timescale variability observed in the TESS light curves can be
attributed to changes in the accretion rate, but note significant
scatter between separate nights and objects. We identify hints of time
lags within our data set that increase at shorter wavelengths, which
we suggest may be evidence of longitudinal density stratification of
the accretion column. Our results highlight that contemporaneous,
multiwavelength observations remain critical for providing context for
the observed variability of these stars.
Description:
We obtained UBVRI optical photometry for each object using the Large
Monolithic Imager on the 4.3m Lowell Discovery Telescope (LDT) in
Happy Jack, AZ. A set of UBVRI images were obtained for each target
during each of six nights spread over 2019 December (specifically 2019
December 2, 2019 December 7, 2019 December 10, 2019 December 13, 2019
December 18, and 2019 December 21 UT). These data were taken
simultaneously with the TESS observations (with the exception of some
of the observations on 2019 December 10, which occurred near the start
of the TESS downlink gap).
Objects:
---------------------------------------------
RA (2000) DE Designation(s)
---------------------------------------------
04 55 10.98 +30 21 59.3 GM Aur = V* GM Aur
---------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 228 84 The 4.3m Lowell Discovery Telescope (LDT) UBVRI
photometry and M measurements for the entire sample
table2.dat 61 502 LDT U-band monitoring & M measurements of GM Aur
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See also:
I/337 : Gaia DR1 (Gaia Collaboration, 2016)
I/350 : Gaia EDR3 (Gaia Collaboration, 2020)
J/ApJS/101/117 : UBVRIJHKLMNQ photometry in Taurus-Auriga (Kenyon+ 1995)
J/A+A/337/403 : Low-mass stars evolutionary models (Baraffe+ 1998)
J/ApJ/771/129 : Submillimetric Class II sources of Taurus (Andrews+, 2013)
J/AJ/146/131 : UBVRI standard stars at +50° declination (Landolt, 2013)
J/AJ/147/82 : Monitoring of disk-bearing stars in NGC 2264 (Cody+, 2014)
J/ApJ/786/97 : Photospheric properties of T Tauri stars (Herczeg+, 2014)
J/A+A/581/A66 : UV variability and accretion in NGC 2264 (Venuti+, 2015)
J/A+A/586/A47 : Accretion process in NGC 2264 (Sousa+, 2016)
J/ApJ/838/150 : The Taurus-Auriga ecosystem. I. (Kraus+, 2017)
J/AJ/156/271 : The stellar membership of the Taurus SFR (Luhman, 2018)
J/ApJ/872/158 : Survey of Class II sources in Taurus with ALMA (Akeson+, 2019)
J/AJ/157/144 : Protoplanetary disk masses in Taurus (Ballering+, 2019)
J/A+A/628/A68 : SPHERE image of RY Tau (Garufi+, 2019)
J/AJ/162/110 : Gaia EDR3 census of Taurus-Auriga complex (Krolikowski+, 2021)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- Name Source identifier
12- 24 F13.7 d MBJD [58819/58839] Modified Barycentric Julian
Date of 1st exposure start in UBVRI
set (1)
26- 30 F5.2 mag Umag [11/18.2]? Apparent U band Vega magnitude
32- 35 F4.2 mag e_Umag [0/0.3]? Uncertainty in Umag see
Section 2.2
37- 54 F18.12 d MBJD-U [58819/58839]? Modified Barycentric Julian
Date of U band start (1)
56- 61 F6.3 mag Bmag [10.5/17] Apparent B band Vega magnitude
63- 67 F5.3 mag e_Bmag [0.009/0.07] Uncertainty in Bmag;
see Section 2.2
69- 86 F18.12 d MBJD-B [58819/58839] Modified Barycentric Julian
Date of B band start (1)
88- 93 F6.3 mag Vmag [9.62/15.3] Apparent V band Vega magnitude
95- 99 F5.3 mag e_Vmag [0.02/0.04] Uncertainty in Vmag;
see Section 2.2
101-118 F18.12 d MBJD-V [58819/58839] Modified Barycentric Julian
Date of V band start (1)
120-125 F6.3 mag Rmag [8.92/13.7] Apparent R band Vega magnitude
127-131 F5.3 mag e_Rmag [0.02/0.04] Uncertainty in Rmag;
see Section 2.2
133-150 F18.12 d MBJD-R [58819/58839] Modified Barycentric Julian
Date of R band start (1)
152-157 F6.3 mag Imag [8.23/12.2] Apparent I band Vega magnitude
159-163 F5.3 mag e_Imag [0.02/0.06] Uncertainty in Imag;
see Section 2.2
165-182 F18.12 d MBJD-I [58819/58839] Modified Barycentric Julian
Date of I band start (1)
184-189 F6.3 10-8Msun/yr MdotF [0.07/15.4]? Mass accretion rate assuming
fixed stellar parameters in Table 4
191-196 F6.3 10-8Msun/yr MdotR [0.07/15.5]? 50th percentile of random
uncertainty mass accretion rate
distribution (2)
198-203 F6.3 10-8Msun/yr E_MdotR [0.02/3.0]? Upper uncertainty in MdotR;
84th - 50th percentile
205-210 F6.3 10-8Msun/yr e_MdotR [0.01/3.0]? Lower uncertainty in MdotR;
50th - 16th percentile
212-216 F5.2 10-8Msun/yr MdotS [0.08/21.0]? 50th percentile of systematic
uncertainty mass accretion rate
distribution (3)
218-222 F5.2 10-8Msun/yr E_MdotS [0.08/7.0]? Upper uncertainty in MdotS;
84th - 50th percentile
224-228 F5.2 10-8Msun/yr e_MdotS [0.05/5.0]? Lower uncertainty in MdotS;
50th - 16th percentile
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Note (1): In the TDB time frame.
Note (2): MdotR and the associated uncertainties were found by
re-sampling measurement uncertainties.
Note (3): MdotS and the associated uncertainties were found by
re-sampling both measurement uncertainties
and system parameters.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 F13.7 d MBJD [58819/58839] Modified Barycentric Julian
Date (1)
15- 20 F6.3 mag Umag [12.9/14.1] Apparent U band Vega magnitude
22- 25 F4.2 mag e_Umag [0.08/2] Uncertainty in Umag
27- 32 F6.4 10-8Msun/yr MdotF [0.51/1.71] Mass accretion rate assuming
fixed stellar parameters in Table 4 (2)
34- 37 F4.2 10-8Msun/yr MdotR [0.51/1.7] 50th percentile of random
uncertainty mass accretion rate
distribution (2)
39- 42 F4.2 10-8Msun/yr E_MdotR [0.06/2] Upper uncertainty in MdotR;
84th - 50th percentile
44- 47 F4.2 10-8Msun/yr e_MdotR [0.05/0.6] Lower uncertainty in MdotR;
50th - 16th percentile
49- 52 F4.2 10-8Msun/yr MdotS [0.51/1.8] 50th percentile of systematic
uncertainty mass accretion rate
distribution (2)
54- 56 F3.1 10-8Msun/yr E_MdotS [0.3/2] Upper uncertainty in MdotS;
84th - 50th percentile
58- 61 F4.2 10-8Msun/yr e_MdotS [0.2/0.7] Lower uncertainty in MdotS;
50th - 16th percentile
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Note (1): In the TDB time frame.
Note (2): The scatter in adjacent values of Mdot, which is typically on the
order of 0.01e-8 to 0.03e-8 Msun/yr, is a better estimate of true
random uncertainty since it is set by the internal precision of
our differential photometry. Note that some of that scatter may
be caused by real variability.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 06-Jun-2024