2012A&A...547A.104B


Query : 2012A&A...547A.104B

2012A&A...547A.104B - Astronomy and Astrophysics, volume 547A, 104-104 (2012/11-1)

The Chamaeleon II low-mass star-forming region: radial velocities, elemental abundances, and accretion properties.

BIAZZO K., ALCALA J.M., COVINO E., FRASCA A., GETMAN F. and SPEZZI L.

Abstract (from CDS):

Knowledge of radial velocities, elemental abundances, and accretion properties of members of star-forming regions is important for our understanding of stellar and planetary formation. While infrared observations reveal the evolutionary status of the disk, optical spectroscopy is fundamental to acquire information on the properties of the central star and on the accretion characteristics. Existing 2MASS archive data and the Spitzer c2d survey of the ChamaeleonII dark cloud have provided disk properties of a large number of young stars. We complement these data with optical spectroscopy with the aim of providing physical stellar parameters and accretion properties. We use FLAMES/UVES and FLAMES/GIRAFFE spectroscopic observations of 40 members of the ChamaeleonII star-forming region to measure radial velocities through cross-correlation technique, lithium abundances by means of curves of growth, and for a suitable star elemental abundances of Fe, Al, Si, Ca, Ti, and Ni using the code MOOG. From the equivalent widths of the Hα, Hβ, and the HeI λ5876, λ6678, λ7065Å emission lines, we estimate the mass accretion rates, {dot}(M)acc, for all the objects. We derive a radial velocity distribution for the ChamaeleonII stars, which is peaked at <Vrad≥11.4±2.0k/s. We find dependencies of {dot}(M)acc∝M*1.3 and of {dot}(M)acc∝Age–0.82 in the ∼0.1-1.0M mass regime, as well as a mean mass accretion rate for Chamaeleon II of {dot}(M)acc∼7+26–5x10–10M_☉/yr. We also establish a relationship between the HeI λ7065Å line emission and the accretion luminosity. The radial velocity distributions of stars and gas in ChamaeleonII are consistent. The spread in {dot}(M)acc at a given stellar mass is about one order of magnitude and can not be ascribed entirely to short timescale variability. Analyzing the relation between {dot}(M)acc and the colors in Spitzer c2d and 2MASS bands, we find indications that the inner disk changes from optically thick to optically thin at {dot}(M)acc∼10–10M_☉/yr. Finally, the disk fraction is consistent with the age of ChamaeleonII.

Abstract Copyright:

Journal keyword(s): accretion, accretion disks - stars: pre-main sequence - stars: low-mass - stars: abundances - stars: kinematics and dynamics - open clusters and associations: individual: Chamaeleon II

Simbad objects: 53

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Number of rows : 53
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024
#notes
1 NAME Magellanic Clouds GrG 03 00 -71.0           ~ 6897 1
2 Cl Melotte 22 OpC 03 46 24.2 +24 06 50           ~ 3387 0
3 NAME Tau-Aur Complex SFR 04 30 +25.0           ~ 1343 0
4 NAME Taurus Complex SFR 04 41.0 +25 52           ~ 4316 0
5 V* YY Ori Or* 05 34 47.5333529424 -05 57 56.956399776     13.20   12.95 K2IVe 130 0
6 NAME Orion Nebula Cluster OpC 05 35.0 -05 29           ~ 2285 0
7 * sig Ori Y*O 05 38 44.7653828520 -02 36 00.283179888 2.54 3.58 3.79 3.87 4.11 O9.5V+B0.2V(n) 794 0
8 NAME Cha 1 MoC 11 06 48 -77 18.0           ~ 1141 1
9 NAME Chamaeleon Region SFR 11 55 -78.0           ~ 797 0
10 V* DK Cha TT* 12 53 17.2111480272 -77 07 10.736046012           F0e 139 0
11 NAME Cha II MoC 12 54 -77.2           ~ 333 0
12 NAME Sz 46N Em* 12 56 33.6498681600 -76 45 45.520705728   17.66 16.19 14.61 13.16 M1 30 1
13 Sz 47 Y*O 12 56 58.6633997016 -76 47 06.861163092   14.5       ~ 20 0
14 IRAS 12535-7623 Y*O 12 57 11.6949853032 -76 40 11.291754000   17.20 15.00     M0e 42 0
15 2MASS J12585614-7630104 Y*O 12 58 56.1408783960 -76 30 10.544207580       16.39 14.38 M5 7 0
16 2MASS J12590984-7651037 Y*O 12 59 09.8766268200 -76 51 03.756572676           M5.5 14 0
17 2MASS J12591013-7712139 Y*O 12 59 10.1600323896 -77 12 13.864063428           M0 13 0
18 IRAS 12556-7731 LP* 12 59 26.3852196576 -77 47 08.619604404   15.039 13.136 12.748   M5 23 0
19 RX J1300.9-7708B * 13 00 53.2360864848 -77 09 09.303222348           ~ 9 0
20 Sz 49 Y*O 13 00 53.2473650928 -76 54 15.206649912   15.6       M0.5 43 0
21 RX J1300.9-7708 Y*O 13 00 53.46120 -77 09 08.6580           M1 23 0
22 2MASS J13005534-7708296 Y*O 13 00 55.3405780272 -77 08 29.630496552       14.93 13.29 M2.5 8 0
23 Sz 50 Y*O 13 00 55.3820751133 -77 10 22.247668674   17.64 16.01     M3 45 0
24 ASAS J130056-7653.9 TT* 13 00 56.2347315648 -76 54 02.375615448   13.79 12.35 11.93 10.446 K5 15 0
25 2MASS J13005927-7714027 Y*O 13 00 59.2811230320 -77 14 02.848183656         16.26 ~ 24 0
26 Sz 51 Or* 13 01 58.8991295760 -77 51 21.848767020   15.38       K8.5 40 0
27 V* CM Cha TT* 13 02 13.5244979592 -76 37 57.818696016   14.70 13.40     K7IVe 42 0
28 2MASS J13022287-7734494 Y*O 13 02 22.8483923232 -77 34 49.479406140           M5 17 0
29 2MASS J13030444-7707027 TT* 13 03 04.4591495760 -77 07 02.759053872     13.23     M0 16 1
30 2MASS J13030905-7755596 Y*O 13 03 09.0555653520 -77 55 59.569205808           M4.5 9 0
31 Hn 23 Y*O 13 04 24.1091476992 -76 50 01.203848088           K7e 24 0
32 Sz 52 Y*O 13 04 24.8675032320 -77 52 30.280923336   17.7     14.66 M2.5 28 0
33 Hn 24 Y*O 13 04 55.7191411392 -77 39 49.222352340           M0 31 0
34 Hn 25 Y*O 13 05 08.5232959920 -77 33 42.630661188           M2.5 23 0
35 Sz 53 Y*O 13 05 12.6752612232 -77 30 52.566390396   17.85 16.59     M1 31 0
36 Hen 3-854 Or* 13 05 20.6574078672 -77 39 01.506188880   13.88 12.40     K5 45 0
37 2MASS J13052169-7738102 Y*O 13 05 21.6550009440 -77 38 10.259255184           ~ 13 0
38 Sz 55 Y*O 13 06 30.5147352624 -77 34 00.166145700   18.90 17.49     M2 19 0
39 Sz 56 Y*O 13 06 38.7881087232 -77 30 35.274308688   18.53 17.08     M4 22 0
40 Sz 57 Y*O 13 06 56.5765655088 -77 23 09.640416696   19.56 17.70     M5 20 0
41 Sz 58 Em* 13 06 57.4252298184 -77 23 41.593041672   17.89 16.01     K5 32 0
42 V* BK Cha Or* 13 07 09.247848 -77 30 30.56004   16.11 14.58 14.41   K7 32 0
43 2MASS J13071806-7740529 Y*O 13 07 18.0439003536 -77 40 53.043429684         16.18 M4.5 19 0
44 NAME Sz 60W Y*O 13 07 22.3510937688 -77 37 22.664073396   17.35 15.77 15.96 13.45 M1e 10 0
45 Hn 26 Y*O 13 07 48.4988968944 -77 41 21.572667204           M2 23 0
46 V* BM Cha Or* 13 08 06.2695235808 -77 55 05.329818156   16.77 14.60     K5 55 0
47 2MASS J13082714-7743232 Y*O 13 08 27.1778458152 -77 43 23.297498148         16.55 M4.5 20 0
48 2MASS J13090987-7709437 Y*O 13 09 09.9088695936 -77 09 43.801176816       15.37 14.04 M0.5 12 0
49 2MASS J13091071-7709443 Y*O 13 09 10.71600 -77 09 44.3628       13.47 12.42 M1.5 8 0
50 Sz 62 Y*O 13 09 50.36808 -77 57 24.0228   16.99 15.55 14.838   M2.5 33 0
51 Sz 63 Y*O 13 10 04.1819222640 -77 10 44.849941680   15.2       M3 20 0
52 2MASS J13125238-7739182 Y*O 13 12 52.38 -77 39 18.3           M4.5 7 0
53 Sz 64 Y*O 13 14 03.7124279328 -77 53 07.576738116   16.3       M5 17 0

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2023.11.30-02:59:00

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