2011ApJ...734...31F


C.D.S. - SIMBAD4 rel 1.7 - 2019.10.23CEST10:57:12

2011ApJ...734...31F - Astrophys. J., 734, 31 (2011/June-2)

The far-ultraviolet "Continuum" in protoplanetary disk systems. II. Carbon monoxide fourth positive emission and absorption.

FRANCE K., SCHINDHELM E., BURGH E.B., HERCZEG G.J., HARPER G.M., BROWN A., GREEN J.C., LINSKY J.L., YANG H., ABGRALL H., ARDILA D.R., BERGIN E., BETHELL T., BROWN J.M., CALVET N., ESPAILLAT C., GREGORY S.G., HILLENBRAND L.A., HUSSAIN G., INGLEBY L., JOHNS-KRULL C.M., ROUEFF E., VALENTI J.A. and WALTER F.M.

Abstract (from CDS):

We exploit the high sensitivity and moderate spectral resolution of the Hubble Space Telescope Cosmic Origins Spectrograph to detect far-ultraviolet (UV) spectral features of carbon monoxide (CO) present in the inner regions of protoplanetary disks for the first time. We present spectra of the classical T Tauri stars HN Tau, RECX-11, and V4046 Sgr, representative of a range of CO radiative processes. HN Tau shows CO bands in absorption against the accretion continuum. The CO absorption most likely arises in warm inner disk gas. We measure a CO column density and rotational excitation temperature of N(CO) = (2±1)x1017/cm2 and Trot(CO) 500±200 K for the absorbing gas. We also detect CO A-X band emission in RECX-11 and V4046 Sgr, excited by UV line photons, predominantly H I Lyα. All three objects show emission from CO bands at λ > 1560 Å, which may be excited by a combination of UV photons and collisions with non-thermal electrons. In previous observations these emission processes were not accounted for due to blending with emission from the accretion shock, collisionally excited H2, and photo-excited H2, all of which appeared as a "continuum" whose components could not be separated. The CO emission spectrum is strongly dependent upon the shape of the incident stellar Lyα emission profile. We find CO parameters in the range: N(CO) ∼ 1018-1019/cm2, Trot(CO) ≳ 300 K for the Lyα-pumped emission. We combine these results with recent work on photo-excited and collisionally excited H2emission, concluding that the observations of UV-emitting CO and H2 are consistent with a common spatial origin. We suggest that the CO/H2 ratio (≡ N(CO)/N(H2)) in the inner disk is ∼1, a transition between the much lower interstellar value and the higher value observed in solar system comets today, a result that will require future observational and theoretical study to confirm.

Abstract Copyright:

Journal keyword(s): protoplanetary disks - stars: individual (HN Tau, RECX-11, V4046 Sgr)

Simbad objects: 14

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Number of rows : 14

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2019
#notes
1 V* DF Tau TT* 04 27 02.7917481241 +25 42 22.456361256 11.97 12.25 11.42 10.31 9.14 M3Ve 454 1
2 NAME Tau-Aur Region SFR 04 30 +25.0           ~ 1180 1
3 NAME HN Tau B TT* 04 33 39.2235103174 +17 51 49.871502091     18.1     M4e 27 0
4 V* HN Tau TT* 04 33 39.3612389736 +17 51 52.302839814   14.76 13.40 13.05   K5e 214 0
5 NAME Taurus Dark Cloud SFR 04 41.0 +25 52           ~ 3310 0
6 V* AB Aur Ae* 04 55 45.8459978418 +30 33 04.293281305 7.20 7.16 7.05 6.96 6.70 A0Ve 898 2
7 * bet Pic PM* 05 47 17.0876901 -51 03 59.441135 4.13 4.03 3.86 3.74 3.58 A6V 1597 1
8 NAME Taurus Cluster Cl* 06 10.1 +09 05           ~ 62 0
9 HD 44179 pA* 06 19 58.2185496 -10 38 14.706068 9.51 9.33 9.02     B9Ib/II 704 0
10 * eta Cha * 08 41 19.5144242735 -78 57 48.102318990 5.02 5.351 5.453     B8V 208 0
11 NAME eta Cha Association MGr 08 42 06 -79 01.6           ~ 299 0
12 V* EP Cha Or* 08 47 01.6438574841 -78 59 34.378576588     11.1     K5 70 0
13 NAME beta Pic Moving Group MGr 14 30 -42.0           ~ 524 0
14 HD 319139 BY* 18 14 10.4818974563 -32 47 34.516106830   11.47 10.68   9.11 K5+K7 271 0

    Equat.    Gal    SGal    Ecl

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2019.10.23-10:57:12

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