2010A&A...516A.110M


Query : 2010A&A...516A.110M

2010A&A...516A.110M - Astronomy and Astrophysics, volume 516, A110-110 (2010/6-3)

Where is the warm H2? A search for H2 emission from disks around Herbig Ae/Be stars.

MARTIN-ZAIEDI C., AUGEREAU J.-C., MENARD F., OLOFSSON J., CARMONA A., PINTE C. and HABART E.

Abstract (from CDS):

Mid-infrared (mid-IR) emission lines of molecular hydrogen (H2) are useful probes to determine the mass of warm gas present in the surface layers of circumstellar disks. In the past years, numerous observations of Herbig Ae/Be stars (HAeBes) have been performed, but only two detections of H2 mid-IR emission toward HD 97048 and AB Aur have been reported. We aim at tracing the warm gas in the circumstellar environment of five additional HAeBes with gas-rich environments and/or physical characteristics close to those of AB Aur and/or HD 97048, to discuss whether the detections toward these two objects are suggestive of peculiar conditions for the observed gas. We search for the H2 S(1) emission line at 17.035µm using high-resolution mid-IR spectra obtained with VLT/VISIR, and complemented by CH molecule observations with VLT/UVES. We gather the H2 measurements from the literature to put the new results in context and search for a correlation with some disk properties. None of the five VISIR targets shows evidence for H2 emission at 17.035µm. From the 3σ upper limits on the integrated line fluxes we constrain the amount of optically thin warm (>150K) gas to be less than ∼1.4MJup in the disk surface layers. There are now 20 HAeBes observed with VISIR and TEXES instruments to search for warm H2, but only two detections (HD 97048 and AB Aur) were made so far. We find that the two stars with detected warm H2 show at the same time high 30/13µm flux ratios and large PAH line fluxes at 8.6 and 11.3µm compared to the bulk of observed HAeBes and have emission CO lines detected at 4.7µm. We detect the CH 4300.3Å absorption line toward both HD 97048 and AB Aur with UVES. The CH to H2 abundance ratios that this would imply if it were to arise from the same component as well as the radial velocity of the CH lines both suggest that CH arises from a surrounding envelope, while the detected H2 would reside in the disk. The two detections of the S(1) line in the disks of HD 97048 and AB Aur suggest either peculiar physical conditions or a particular stage of evolution. New instruments such as Herschel/ PACS should bring significant new data for the constraints of thermodynamics in young disks by observing the gas and the dust simultaneously.

Abstract Copyright:

Journal keyword(s): circumstellar matter - stars: formation - stars: pre-main sequence - ISM: molecules

Simbad objects: 22

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Number of rows : 22
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 * 49 Cet PM* 01 34 37.7786780856 -15 40 34.898673000   5.667 5.607   5.54 A1V 279 0
2 V* V892 Tau Ae* 04 18 40.6157618376 +28 19 15.625058880   16.6 14.69 14.35   A0Ve 285 0
3 V* AB Aur Ae* 04 55 45.8458932216 +30 33 04.292077032 7.20 7.16 7.05 6.96 6.70 A0Ve 1014 2
4 V* UX Ori Ae* 05 04 29.9878898040 -03 47 14.286732072 10.25 10.93 8.70 9.62 9.43 A4IVe 354 1
5 HD 36112 Ae* 05 30 27.5285630040 +25 19 57.076288752   8.57 8.27     A8Ve 432 0
6 HD 250550 Ae* 06 01 59.9892055464 +16 30 56.727549864   9.60 9.593 9.64   B9e 239 1
7 HD 45677 Be* 06 28 17.4219710352 -13 03 11.128860972 7.86 8.52 8.50 8.11 8.01 B2IV/V[e] 322 0
8 HD 259431 Ae* 06 33 05.1906369144 +10 19 19.982565336 8.39 8.95 8.72     B6ep 277 1
9 * q Car LP* 10 17 04.9753050 -61 19 56.288301   4.899 3.350     K2.5II 136 0
10 HD 97048 Ae* 11 08 03.3109731720 -77 39 17.490777444 9.03 8.76 9.00   8.64 A0Vep 515 0
11 HD 98922 Be* 11 22 31.6743077592 -53 22 11.457008148   6.80 6.76     B9Ve 126 1
12 HD 100453 Ae* 11 33 05.5766482920 -54 19 28.547100696   8.09 7.79     A9Ve 254 1
13 HD 100546 Be* 11 33 25.4408872296 -70 11 41.241297948   6.71 6.30   6.64 A0VaekB8_lB 746 1
14 HD 101412 Be* 11 39 44.4564911064 -60 10 27.719780304   9.465 9.288     A3VaekA0mA0_lB 131 0
15 V* DX Cha Ae* 12 00 05.0868602544 -78 11 34.565724312   6.81 6.60     A0_sh 331 0
16 HD 142666 TT* 15 56 40.0221861696 -22 01 40.005872148 9.41 9.37 8.82 8.31 8.01 F0V_sh 246 0
17 HD 142527 Ae* 15 56 41.8882637904 -42 19 23.248281828   9.04 8.34     F6III 584 1
18 HD 150193 Be* 16 40 17.9243127240 -23 53 45.193372692 9.69 9.32 8.79 8.41   B9.5Ve 307 0
19 HD 163296 Ae* 17 56 21.2881851168 -21 57 21.871819008 7.00 6.93 6.85 6.86 6.67 A1Vep 1004 0
20 HD 169142 Ae* 18 24 29.7799891464 -29 46 49.327400568   8.42 8.16     F1VekA3mA3_lB? 409 2
21 V* VV Ser Ae* 18 28 47.8620017808 +00 08 39.923474964 12.99 12.63 11.80 11.01 10.24 A5Ve 242 0
22 * alf Tuc SB* 22 18 30.0947834 -60 15 34.526307 5.75 4.18 2.82 1.76 1.02 K3III 127 0

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2023.02.07-16:59:16

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