2013ApJ...779..178P


C.D.S. - SIMBAD4 rel 1.7 - 2020.02.18CET05:24:58

2013ApJ...779..178P - Astrophys. J., 779, 178 (2013/December-3)

The atomic and molecular content of disks around very low-mass stars and brown dwarfs.

PASCUCCI I., HERCZEG G., CARR J.S. and BRUDERER S.

Abstract (from CDS):

There is growing observational evidence that disk evolution is stellar-mass-dependent. Here, we show that these dependencies extend to the atomic and molecular content of disk atmospheres. We analyze a unique dataset of high-resolution Spitzer/IRS spectra from eight very low mass star and brown dwarf disks. We report the first detections of Ne+, H2, CO2, and tentative detections of H2 O toward these faint and low-mass disks. Two of our [Ne II] 12.81 µm emission lines likely trace the hot ( ≥ 5000 K) disk surface irradiated by X-ray photons from the central stellar/sub-stellar object. The H2S(2) and S(1) fluxes are consistent with arising below the fully or partially ionized surface traced by the [Ne II] emission in gas at ∼600 K. We confirm the higher C2H2/HCN flux and column density ratio in brown dwarf disks previously noted from low-resolution IRS spectra. Our high-resolution spectra also show that the HCN/H2O fluxes of brown dwarf disks are on average higher than those of T Tauri disks. Our LTE modeling hints that this difference extends to column density ratios if H2 O lines trace warm ≥ 600 K disk gas. These trends suggest that the inner regions of brown dwarf disks have a lower O/C ratio than those of T Tauri disks, which may result from a more efficient formation of non-migrating icy planetesimals. An O/C = 1, as inferred from our analysis, would have profound implications on the bulk composition of rocky planets that can form around very low mass stars and brown dwarfs.

Abstract Copyright:

Journal keyword(s): accretion, accretion disks - brown dwarfs - protoplanetary disks - stars: low-mass - stars: pre-main sequence

Simbad objects: 16

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Number of rows : 16

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 NAME DG Tau B Y*O 04 27 02.666 +26 05 30.38           ~ 128 1
2 V* DK Tau TT* 04 30 44.251 +26 01 24.47 13.32 13.14 11.90 12.58   K7e+K7e 291 0
3 V* AA Tau TT* 04 34 55.4222683130 +24 28 53.038273587 13.14 13.34 12.20     K5Ve 610 0
4 2MASS J04381486+2611399 BD* 04 38 14.8833303682 +26 11 39.971794234       20.33 17.84 M7e 49 0
5 2MASS J04390163+2336029 TT* 04 39 01.6333473875 +23 36 02.959278320   16.7   15.2 12.8 M6 31 0
6 2MASS J04390396+2544264 BD* 04 39 03.9603916514 +25 44 26.337817736       18.40 15.40 M7IVe 49 0
7 IRAS S04414+2506 BD* 04 44 27.1421731772 +25 12 16.439761677           M7e 59 0
8 2MASS J05180285+2327127 TT* 05 18 02.8508651036 +23 27 12.680925450   18.6   17.2 15.3 M5 7 0
9 NAME Cha I MoC 11 06 48 -77 18.0           ~ 946 1
10 2MASS J15582981-2310077 TT* 15 58 29.8128803537 -23 10 07.758366228   17.5       M3 34 0
11 HD 325367 TT* 16 03 05.4914377137 -40 18 25.426543472   11.40 8.50     M0 272 0
12 2MASS J16053215-1933159 TT* 16 05 32.1520336623 -19 33 16.014934774   19.0       M5 25 0
13 NAME Upper Sco Association As* 16 12 -23.4           ~ 975 1
14 2MASS J16222160-2217307 pr* 16 22 21.6005040709 -22 17 30.762527710       18.0 15.5 M5 16 0
15 NOVA Sco 1863 No* 16 22 30.7782086963 -17 52 43.162570042   8.80 8.70     F8+K2 460 0
16 * ksi Dra PM* 17 53 31.7296234 +56 52 21.514262 6.14 4.93 3.75 2.92 2.33 K2III 251 0

    Equat.    Gal    SGal    Ecl

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2020.02.18-05:24:58

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