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 - 2021
#notes
1 NAME Magellanic Clouds GrG 03 00 -71.0           ~ 6043 1
2 Cl Melotte 22 OpC 03 47 00 +24 07.0           ~ 3121 0
3 NAME Tau-Aur Complex SFR 04 30 +25.0           ~ 1264 0
4 NAME Taurus Complex SFR 04 41.0 +25 52           ~ 3787 0
5 V* YY Ori Or* 05 34 47.5333702377 -05 57 56.956038462     13.20   12.95 K2IVe 126 0
6 NAME Orion Nebula Cluster OpC 05 35.0 -05 29           ~ 2083 1
7 * sig Ori Y*O 05 38 44.7665260139 -02 36 00.284709290 2.54 3.58 3.79 3.87 4.11 O9.5V 764 0
8 NAME Cha 1 MoC 11 06 48 -77 18.0           ~ 1031 1
9 NAME Chamaeleon Region SFR 11 55 -78.0           ~ 720 0
10 V* DK Cha Or* 12 53 17.2028372976 -77 07 10.727661977           F0 133 0
11 NAME Cha II MoC 12 54 -77.2           ~ 309 0
12 NAME Sz 46N Em* 12 56 33.6502849173 -76 45 45.519366209   17.66 16.19 14.61 13.16 M1 25 1
13 Sz 47 Y*O 12 56 58.6637589982 -76 47 06.862774460   14.5       ~ 19 0
14 IRAS 12535-7623 Y*O 12 57 11.6976232932 -76 40 11.310030727   17.20 15.00     M0e 38 0
15 2MASS J12585614-7630104 Y*O 12 58 56.1415313573 -76 30 10.541050681       16.39 14.38 M5 7 0
16 2MASS J12590984-7651037 Y*O 12 59 09.84888 -76 51 03.7584           M5.5 13 0
17 2MASS J12591013-7712139 Y*O 12 59 10.1577034739 -77 12 13.864910778           M0 13 0
18 UCAC3 25-31227 Y*O 12 59 26.3851784166 -77 47 08.619085474   15.039 13.136 12.748   M5 21 0
19 RX J1300.9-7708B * 13 00 53.2348603800 -77 09 09.305136886           ~ 9 0
20 Sz 49 Y*O 13 00 53.2477697970 -76 54 15.207461632   15.6       M0.5 40 0
21 RX J1300.9-7708 Y*O 13 00 53.46120 -77 09 08.6580           M1 22 0
22 2MASS J13005534-7708296 Y*O 13 00 55.3390968080 -77 08 29.631545749       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 41 0
24 2MASS J13005622-7654021 TT* 13 00 56.2331903449 -76 54 02.371042013   13.79 12.35 11.93 10.446 K5 15 0
25 2MASS J13005927-7714027 Y*O 13 00 59.2793363460 -77 14 02.847373574         16.26 ~ 21 0
26 Sz 51 Or* 13 01 58.8987922346 -77 51 21.847616559   15.38       K8.5 37 0
27 V* CM Cha TT* 13 02 13.5239808158 -76 37 57.814400439   14.70 13.40     K7IVe 36 0
28 2MASS J13022287-7734494 Y*O 13 02 22.8489131207 -77 34 49.478959627           M5 14 0
29 2MASS J13030444-7707027 TT* 13 03 04.4521881517 -77 07 02.754792580     13.23     M0 16 1
30 2MASS J13030905-7755596 Y*O 13 03 09.0543092763 -77 55 59.570285609           M4.5 9 0
31 Hn 23 Y*O 13 04 24.1088971987 -76 50 01.202943510           K7e 21 0
32 Sz 52 Y*O 13 04 24.8672946643 -77 52 30.284943777   17.7     14.66 M2.5 25 0
33 Hn 24 Y*O 13 04 55.7198158485 -77 39 49.222831504           M0 26 0
34 Hn 25 Y*O 13 05 08.5248918991 -77 33 42.636149865           M2.5 18 0
35 Sz 53 Y*O 13 05 12.6766682155 -77 30 52.567578208   17.85 16.59     M1 25 0
36 Hen 3-854 Or* 13 05 20.6565859165 -77 39 01.505033200   13.88 12.40     K5 41 0
37 2MASS J13052169-7738102 Y*O 13 05 21.6587081112 -77 38 10.261690870           ~ 11 0
38 Sz 55 Y*O 13 06 30.5152951294 -77 34 00.166830312   18.90 17.49     M2 16 0
39 Sz 56 Y*O 13 06 38.7884887625 -77 30 35.273941169   18.53 17.08     M4 18 0
40 Sz 57 Y*O 13 06 56.5768623832 -77 23 09.644270577   19.56 17.70     M5 18 0
41 Sz 58 Em* 13 06 57.4248382326 -77 23 41.603858041   17.89 16.01     K5 27 0
42 V* BK Cha Or* 13 07 09.247848 -77 30 30.56004   16.11 14.58 14.41   K7 30 0
43 2MASS J13071806-7740529 Y*O 13 07 18.0424110318 -77 40 53.041479430         16.18 M4.5 15 0
44 NAME Sz 60W Y*O 13 07 22.3511385283 -77 37 22.665347511   17.35 15.77 15.96 13.45 M1e 8 0
45 Hn 26 Y*O 13 07 48.4981298443 -77 41 21.575697347           M2 18 0
46 V* BM Cha Or* 13 08 06.2694469794 -77 55 05.329360813   16.77 14.60     K5 50 0
47 2MASS J13082714-7743232 Y*O 13 08 27.1757148447 -77 43 23.300629624         16.55 M4.5 16 0
48 2MASS J13090987-7709437 Y*O 13 09 09.87576 -77 09 43.7868       15.37 14.04 M0.5 9 0
49 2MASS J13091071-7709443 Y*O 13 09 10.71600 -77 09 44.3628       13.47 12.42 M1.5 7 0
50 Sz 62 Y*O 13 09 50.37 -77 57 24.0   16.99 15.55     M2.5 30 0
51 Sz 63 Y*O 13 10 04.1816589326 -77 10 44.849934703   15.2       M3 16 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 03.7109829363 -77 53 07.578832622   16.3       M5 15 0

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2021.10.20-17:27:08

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