J/ApJ/756/171 HST far-UV survey of H2 emission of T Tau stars (France+, 2012)
A Hubble Space Telescope survey of H2 emission in the circumstellar
environments of young stars.
France K., Schindhelm E., Herczeg G.J., Brown A., Abgrall H.,
Alexander R.D., Bergin E.A., Brown J.M., Linsky J.L., Roueff E., Yang H.
<Astrophys. J., 756, 171 (2012)>
=2012ApJ...756..171F 2012ApJ...756..171F
ADC_Keywords: YSOs ; Spectra, ultraviolet ; Stars, ages
Keywords: protoplanetary disks; stars: pre-main sequence;
ultraviolet: planetary systems
Abstract:
The formation timescale and final architecture of exoplanetary systems
are closely related to the properties of the molecular disks from
which they form. Observations of the spatial distribution and lifetime
of the molecular gas at planet-forming radii (a<10AU) are important
for understanding the formation and evolution of exoplanetary systems.
Toward this end, we present the largest spectrally resolved survey of
H2 emission around low-mass pre-main-sequence stars compiled to
date. We use a combination of new and archival far-ultraviolet spectra
from the Cosmic Origins Spectrograph and Space Telescope Imaging
Spectrograph instruments on the Hubble Space Telescope to sample
34 T Tauri stars (27 actively accreting Classical T Tauri Stars and 7
non-accreting Weak-lined T Tauri Stars) with ages ranging from ∼1 to
10Myr. We observe fluorescent H2emission, excited by Lyα
photons, in 100% of the accreting sources, including all of the
transitional disks in our sample (CS Cha, DM Tau, GM Aur, UX Tau A,
LkCa 15, HD 135344B, and TW Hya). The spatial distribution of the
emitting gas is inferred from spectrally resolved H2 line profiles.
Some of the emitting gas is produced in outflowing material, but the
majority of H2 emission appears to originate in a rotating disk. For
the disk-dominated targets, the H2 emission originates predominately
at a≲3AU. The emission line widths and inner molecular radii are
found to be roughly consistent with those measured from mid-IR CO
spectra.
Description:
Our sample of 34 T Tauri Stars (TTSs) was assembled from new and
archival observations with HST-COS and -STIS. The majority of the
targets were observed as part of the DAO of Tau guest observing
program (PID 11616; PI: G. Herczeg) and the COS Guaranteed Time
Observing program (PIDs 11533 and 12036; PI: J. Green). Additional
observations of the transitional disk HD 135344B and weak-lined
systems TWA 13A and TWA 13B (PIDs 11828 and 12361; PI: A. Brown) are
presented. A subset of the H2 survey observations have been presented
previously in the literature. Finally, we have included archival Space
Telescope Imaging Spectrograph (STIS) observations of the well-studied
Classical T Tauri Star (CTTS) TW Hya, obtained through StarCAT (Ayres,
2010, Cat. J/ApJS/187/149).
Most of the targets were observed with the medium-resolution far-UV
modes of COS (G130M and G160M). These observations were acquired
between 2009 December and 2011 September.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 62 34 HST target list
table3.dat 198 27 Reddening corrected H2 progression fluxes for
the Classical T Tauri Star (CTTS) sample
refs.dat 89 44 References
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See also:
B/hst : HST Archived Exposures Catalog (STScI, 2007)
J/ApJ/744/121 : Far-UV spectroscopy of T Tau stars (Yang+, 2012)
J/AJ/139/1338 : UV-selected stars in Tau and Upper Sco (Findeisen+, 2010)
J/ApJ/704/531 : The coevality of young binary systems (Kraus+, 2009)
J/A+A/409/1037 : AK Sco ubvy & Geneva differential photometry (Alencar+, 2003)
J/ApJS/147/305 : IUE atlas of pre-main-sequence stars (Valenti+, 2003)
J/AJ/119/3026 : Circumstellar disk candidates in Orion (Rebull+, 2000)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- Name Target name (1)
11 A1 --- m_Name Multiplicity index on Name
13- 16 F4.2 --- Av [0/3.2] Extinction (2)
18- 21 F4.2 [yr] logAge [5.82/7.24] Age (2)
23- 26 F4.2 [yr] e_logAge [0/0.53] logAge uncertainty (2)
28- 31 F4.2 Msun M* [0.19/2.5] Stellar mass (2)
33 A1 --- f_M* [+] +: V4046 Sgr also has 0.69Msun value
35- 39 F5.2 10-8Msun/yr dM/dt [0.01/17.7]? Mass accretion rate (3)
41 A1 --- l_inc Limit flag on inc
42- 43 I2 deg inc [4/85]? Inclination (4)
45- 49 I5 --- PID [8041/12361] HST Proposal ID
51 A1 --- f_PID [S] S: STIS observation was used
53- 62 A10 --- Ref Reference(s) (see refs.dat file)
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Note (1): Targets in the upper group are CTTSs (27 sources), targets in the
lower group are WTTSs (Weak-lined T Tauri Stars).
Note (2): Ages, stellar masses, and extinctions were derived from
pre-main-sequence stellar evolutionary tracks.
Note (3): Mass accretion rates were derived from measurements of the accretion
luminosity.
Note (4): Where possible, inclinations were taken from submillimeter/IR
interferometric studies.
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Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- Name Target name
12- 18 F7.2 10-17W/m2 F3-13 ?=-99.99 F[3,13] (1213.36Å) flux (1)
20- 26 F7.2 10-17W/m2 e_F3-13 ?=-99.99 Uncertainty in F3-13 (1)
28- 34 F7.2 10-17W/m2 F4-13 ?=-99.99 F[4,13] (1213.68Å) flux (1)
36- 42 F7.2 10-17W/m2 e_F4-13 ?=-99.99 Uncertainty in F4-13 (1)
44- 50 F7.2 10-17W/m2 F3-16 ?=-99.99 F[3,16] (1214.47Å) flux (1)
52- 57 F6.2 10-17W/m2 e_F3-16 ?=-99.99 Uncertainty in F3-16 (1)
59- 65 F7.2 10-17W/m2 F4-4 ?=-99.99 F[4,4] (1214.78Å) flux (1)
67- 73 F7.2 10-17W/m2 e_F4-4 ?=-99.99 Uncertainty in F4-4 (1)
75- 81 F7.2 10-17W/m2 F1-7 [2.3/8138] F[1,7] (1215.73Å) flux (1)
83- 88 F6.2 10-17W/m2 e_F1-7 [0.1/777] Uncertainty in F1-7 (1)
90- 97 F8.2 10-17W/m2 F1-4 F[1,4] (1216.07Å) flux (1)
99-105 F7.2 10-17W/m2 e_F1-4 Uncertainty in F1-4 (1)
107-112 F6.2 10-17W/m2 F3-0 ?=-99.99 F[3,0] (1217.04Å) flux (1)
114-119 F6.2 10-17W/m2 e_F3-0 ?=-99.99 Uncertainty in F3-0 (1)
121-127 F7.2 10-17W/m2 F0-1 ?=-99.99 F[0,1] (1217.21Å) flux (1)
129-134 F6.2 10-17W/m2 e_F0-1 ?=-99.99 Uncertainty in F0-1 (1)
136-143 F8.2 10-17W/m2 F0-2 F[0,2] (1217.64Å) flux (1)
145-151 F7.2 10-17W/m2 e_F0-2 Uncertainty in F0-2 (1)
153-159 F7.2 10-17W/m2 F2-12 ?=-99.99 F[2,12] (1217.90Å) flux (1)
161-167 F7.2 10-17W/m2 e_F2-12 ?=-99.99 Uncertainty in F2-12 (1)
169-175 F7.2 10-17W/m2 F2-15 ?=-99.99 F[2,15] (1218.52Å) flux (1)
177-182 F6.2 10-17W/m2 e_F2-15 ?=-99.99 Uncertainty in F2-15 (1)
184-190 F7.2 10-17W/m2 F0-3 ?=-99.99 F[0,3] (1219.09Å) flux (1)
192-198 F7.2 10-17W/m2 e_F0-3 ?=-99.99 Uncertainty in F0-3 (1)
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Note (1): Progression fluxes are in listed in units of 1e-14erg/cm2/s.
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Ref Reference code
4- 22 A19 --- BibCode Bibcode
24- 45 A22 --- Aut Author's name(s)
47- 89 A43 --- Comm Comment
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 14-May-2014