2007A&A...464..615D


C.D.S. - SIMBAD4 rel 1.7 - 2020.12.03CET13:20:45

2007A&A...464..615D - Astronomy and Astrophysics, volume 464, 615-623 (2007/3-3)

Chemistry in disks. I. Deep search for N2H+ in the protoplanetary disks around LkCa 15, MWC 480, and DM Tauri.

DUTREY A., HENNING T., GUILLOTEAU S., SEMENOV D., PIETU V., SCHREYER K., BACMANN A., LAUNHARDT R., PETY J. and GUETH F.

Abstract (from CDS):

To constrain the ionization fraction in protoplanetary disks, we present new high-sensitivity interferometric observations of N2H+ in three disks surrounding DM Tau, LkCa 15, and MWC 480. We used the IRAM PdBI array to observe the N2H+ J=1-0 line and applied a χ2-minimization technique to estimate corresponding column densities. These values are compared, together with HCO+ column densities, to results of a steady-state disk model with a vertical temperature gradient coupled to gas-grain chemistry. We report two N2 H+ detections for LkCa 15 and DM Tau at the 5 σ level and an upper limit for MWC 480. The column density derived from the data for LkCa 15 is much lower than previously reported. The [N2H+/HCO+] ratio is on the order of 0.02-0.03. So far, HCO+ remains the most abundant observed molecular ion in disks. All the observed values generally agree with the modelled column densities of disks at an evolutionary stage of a few million years (within the uncertainty limits), but the radial distribution of the molecules is not reproduced well. The low inferred concentration of N2H+ in three disks around low-mass and intermediate-mass young stars implies that this ion is not a sensitive tracer of the overall disk ionization fraction.

Abstract Copyright:

Journal keyword(s): stars: pre-main sequence - planetary systems: protoplanetary disks - submillimeter

Simbad objects: 12

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Number of rows : 12

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 3C 111 Sy1 04 18 21.2773655604 +38 01 35.801523843   19.75 18.05     ~ 864 1
2 V* GG Tau Or* 04 32 30.3318954228 +17 31 40.834888327 14.84 14.78 13.40 11.54   M0e+M2.0e 658 1
3 V* DM Tau Or* 04 33 48.7335659850 +18 10 09.974471722 14.30 14.82 14.00     M2Ve 524 0
4 EM* LkCa 15 Or* 04 39 17.7912813350 +22 21 03.387667491   13.01 12.03 11.61   K5:Ve 568 1
5 V* AB Aur Ae* 04 55 45.8459978418 +30 33 04.293281305 7.20 7.16 7.05 6.96 6.70 A0Ve 944 2
6 HD 31648 Ae* 04 58 46.2654165113 +29 50 36.990341242 7.84 7.78 7.62 7.76 7.43 A5Vep 404 0
7 LDN 1544 DNe 05 04 16.6 +25 10 48           ~ 706 0
8 NAME [BM89] L1544 cor 05 04 22.5 +25 11 36           ~ 434 1
9 QSO J0530+13 QSO 05 30 56.41672 +13 31 55.1495     20.0 19.35   ~ 885 1
10 V* TW Hya TT* 11 01 51.9054298616 -34 42 17.031550898   11.94 10.50 10.626 9.18 K6Ve 1571 1
11 NAME LDN 483-mm mm 18 17 29.8 -04 39 38           ~ 18 0
12 EM* MWC 349 ** 20 32 45.499080 +40 39 36.74124   15.88 13.15 12.13   Bep 710 0

    Equat.    Gal    SGal    Ecl

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2020.12.03-13:20:45

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