2004ApJ...606..952R


C.D.S. - SIMBAD4 rel 1.7 - 2021.04.16CEST11:12:45

2004ApJ...606..952R - Astrophys. J., 606, 952-968 (2004/May-2)

Hubble Space Telescope WFPC2 study of the Trapezium cluster: the influence of circumstellar disks on the initial mass function.

ROBBERTO M., SONG J., MORA CARRILLO G., BECKWITH S.V.W., MAKIDON R.B. and PANAGIA N.

Abstract (from CDS):

We have performed the first measures of mass accretion rates in the core of the Orion Nebula Cluster. Four adjacent fields centered on the Trapezium stars have been imaged in the U and B bands using the Wide Field Planetary Camera 2 (WFPC2) on board the Hubble Space Telescope. We obtained photometry for 91 stars in the U band (F336W) and 71 stars in the B band (F439W). The WFPC2 archive was also searched to obtain complementary V-band (F547M) and I-band (F791W) photometry. In this paper we focus our attention on a group of 40 stars with known spectral types and complete UBVI WFPC2 photometry. We locate each star on the H-R diagram, considering both the standard ISM reddening law with RV=3.1 and the ``anomalous'' reddening law with RV=5.5 more appropriate for the Orion Nebula. Then we derive the stellar masses and ages by comparing with the evolutionary tracks and isochrones calculated by D'Antona & Mazzitelli and Palla & Stahler. Approximately three-quarters of the sources show excess luminosity in the U band, which we attribute to mass accretion. The known correlation between the U-band excess and the total accretion luminosity, recalibrated for our photometric system, allows us to estimate the accretion rates, which are all found to be in the range 10–8 to 10–12 M/yr. For stars older than 1 Myr, there is some evidence of a relation between mass accretion rates and stellar age. Overall, mass accretion rates appear lower than those measured by other authors in the Orion flanking fields or in Taurus-Auriga. Mass accretion rates remain low even in the vicinity of the 10–5 M/yr birth line of Palla & Stahler, suggesting that in the core of the Trapezium cluster, disk accretion has been recently depressed by an external mechanism. We suggest that the UV radiation generated by the Trapezium OB stars, responsible for the disk evaporation, may also cause the drop of the mass accretion rate. In this scenario, low-mass stars may terminate their pre-main-sequence evolution with masses lower than those they would have reached if disk accretion could have proceeded undisturbed until the final disk consumption. In OB associations the low-mass end of the initial mass function (IMF) may therefore be affected by the rapid evolution of the most massive cluster's stars, causing a surplus of ``accretion-aborted'', very low mass stars and brown dwarfs and a deficit of intermediate-mass stars. This trend is in agreement with recent observations of the IMF in the Trapezium cluster.

Abstract Copyright:

Journal keyword(s): Accretion, Accretion Disks - Galaxy: Open Clusters and Associations: Individual: Name: Orion Nebula Cluster - Stars: Formation - stars: pre-main-sequence

CDS comments: Table 2: BPGS = [GS83] 65 = HD 118180, not HD 132683.

Simbad objects: 60

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Number of rows : 60

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 V* GQ And Er* 00 18 25.8244484426 +44 01 38.091239561   12.84 11.04 10.3   M3.5Ve 246 0
2 HD 4967 PM* 00 51 34.0201514770 -22 54 36.241572330 11.446 10.256 8.954 8.157 7.467 K5V 90 1
3 BD+61 195 PM* 01 02 38.8679928575 +62 20 42.172837073   11.439   8.7   M1.5V 207 0
4 V* VX Ari Er* 02 44 15.5094178798 +25 31 24.117029188 13.363 12.141 10.563 9.49 8.115 dM3 191 0
5 Cl Melotte 25 OpC 04 26 54.00 +15 52 00.0           ~ 2752 0
6 NAME Tau-Aur Complex SFR 04 30 +25.0           ~ 1251 0
7 NAME Orion Nebula Cluster OpC 05 35.0 -05 29           ~ 2050 1
8 JW 395 * 05 35 13.0266332260 -05 22 00.910302673   13.0 18.009   14.840 M2 27 0
9 V* V2232 Ori Or* 05 35 13.1052073786 -05 21 13.318229178   19.731 18.888   15.231 M2.5e 29 0
10 Parenago 1821 Y*O 05 35 13.7427694483 -05 22 21.970532072 17.886 17.435 16.559   13.422 M2e 40 0
11 V* V1496 Ori Or* 05 35 13.8001039312 -05 22 07.024932180   16.184 14.987   12.289 K2e 50 0
12 COUP 600 * 05 35 14.07 -05 22 36.6     15.906   12.799 M3 50 0
13 V* V1328 Ori BY* 05 35 14.2773413378 -05 24 24.668229834 16.297 15.025 13.988 13.13 11.665 K7 57 0
14 [OW94] 147-302 Y*O 05 35 14.65920 -05 23 01.8960     19.12   14.898 M0.5-M2.5 44 0
15 COUP 668 Ir* 05 35 14.900 -05 24 11.80     18.18   14.226 M4 19 0
16 V* V1331 Ori Ro* 05 35 15.3444129558 -05 22 15.587976220   15.777 14.474   11.707 K3e 51 0
17 V* V2270 Ori Or* 05 35 15.4016092493 -05 21 13.957638452     17.795   14.313 M3.5e 30 0
18 V* V348 Ori Or* 05 35 15.6353012097 -05 22 56.457494793   14.352 13.274   10.987 G8-K1 58 0
19 COUP 727 Y*O 05 35 15.6811 -05 25 10.225     18.15 14.97 14.096 M1.5 22 0
20 COUP J053516.0-052146 * 05 35 16.010 -05 21 47.00   13.2 18.013   14.352 M5.5 27 0
21 V* V2284 Ori Or* 05 35 16.1932341819 -05 21 32.381506224   13.2 18.08   14.509 M3e 30 0
22 COUP 796 Y*O 05 35 16.3141556155 -05 20 25.258868594   14.0 18.963   14.885 M5 29 0
23 * tet01 Ori C ** 05 35 16.4664092288 -05 23 22.897102710 4.20 5.15 5.13 4.91 4.73 O7Vp 1299 1
24 NAME Trapezium Cluster As* 05 35 16.5 -05 23 14           ~ 1505 1
25 V* V2299 Ori Or* 05 35 17.0670026413 -05 23 34.055297452 14.962 14.224 13.322   11.118 K1 70 0
26 V* V2302 Ori Or* 05 35 17.2278888014 -05 20 27.731953091   16.987 15.950   13.057 M3 38 0
27 COUP 870 Ir* 05 35 17.2700310816 -05 24 24.212380753     14.23 13.75 14.709 M1 20 0
28 M 42 HII 05 35 17.3 -05 23 28           ~ 3787 0
29 V* V2304 Ori Or* 05 35 17.3685814047 -05 20 14.851220986   19.120 17.744   14.458 M0.5 36 0
30 COUP 879 * 05 35 17.37338 -05 23 04.8794           M4-M6 22 0
31 2MASS J05351768-0524539 Y*O 05 35 17.6971614694 -05 24 54.083001355   12.9 14.90 13.76 14.627 M5.5e 31 0
32 JW 569 Ir* 05 35 17.9473281806 -05 25 21.241278307   13.3 14.92 13.70 14.641 M3.5 26 0
33 2MASS J05351802-0522052 EB* 05 35 18.0305971884 -05 22 05.395532385     19.06   14.694 K0-K3 32 0
34 COUP 955 Y*O 05 35 18.2457511593 -05 23 15.611511284   13.2 16.412   13.933 M2 36 0
35 COUP 954 * 05 35 18.27 -05 23 07.4     17.383   15.090 M4 28 0
36 2MASS J05351851-0520427 Y*O 05 35 18.5212663996 -05 20 42.778786077   14.2     14.894 M3.5 31 0
37 COUP 1000 Y*O 05 35 18.8758831244 -05 23 28.866001060   13.0 18.84   14.673 M0e 34 0
38 COUP 1023 Em* 05 35 19.2128226301 -05 22 50.684661096     17.099   13.882 K5 40 0
39 V* V2354 Ori Or* 05 35 19.6137722672 -05 23 57.343258422   17.280 16.478   14.205 K8 34 0
40 V* V1399 Ori Or* 05 35 21.0492702938 -05 23 48.989001884 14.154 13.231 12.376   10.605 G8 60 0
41 V* V2375 Ori Or* 05 35 21.2465977314 -05 22 59.522678791   19.068 18.244   14.850 M3 38 0
42 V* V1524 Ori Or* 05 35 21.35640 -05 23 45.4992   17.621 16.471   13.850 M1+M3.5 37 0
43 V* V1524 Ori A * 05 35 21.3656261424 -05 23 45.441405876           ~ 39 0
44 V* V1282 Ori Or* 05 35 21.7333967814 -05 26 44.446182162   18.685 17.616 15.77 14.421 M2.7 39 1
45 V* V2383 Ori Or* 05 35 21.7742369950 -05 23 39.333574655   13.0 17.73   14.467 K6 39 0
46 [H97b] 20176 Ir* 05 35 22.1567166950 -05 22 13.423142891     20.28   16.067 M5 21 0
47 V* V1527 Ori Or* 05 35 22.5473794925 -05 23 43.721695042   16.607 15.496   13.058 M0 41 0
48 JW 726 * 05 35 22.9717911255 -05 22 41.610540564   14.8 19.24   15.128 K5-K7 30 0
49 2MASS J05352365-0523319 Y*O 05 35 23.6444 -05 23 31.750   13.3 16.326   13.604 K5 28 0
50 V* V2425 Ori Or* 05 35 24.5149166134 -05 25 01.611170548   18.063 17.627   14.578 M1e 28 0
51 V* V2441 Ori Or* 05 35 25.7180987612 -05 23 09.357042424   14.2 17.149   13.907 K8e 38 0
52 NAME Ori A MoC 05 38 -07.1           ~ 2756 0
53 NGC 2632 OpC 08 40 24 +19 40.0           ~ 1296 0
54 NAME Cha 1 MoC 11 06 48 -77 18.0           ~ 1014 1
55 BD+38 2457 PM* 13 34 05.5571875174 +37 38 14.549479833   11.02   9.3   K8 30 0
56 HD 118180 * 13 35 01.7092795327 +12 30 50.247528361   7.606 6.552     K0 13 0
57 HD 132683 PM* 15 00 43.4131263202 -11 08 06.466971804 12.137 10.865 9.472 8.607 7.822 K8Vk 67 0
58 * pi.01 UMi A PM* 15 29 11.1859884174 +80 26 54.967827534   7.25   6.2   G1.5V(n) 109 0
59 HD 154712 PM* 17 03 18.6604484162 +59 35 07.279801308   9.69   8.0   K4V 68 0
60 HD 190470 PM* 20 04 10.0459183461 +25 47 24.821083939 9.462 8.709 7.767 7.259 6.817 K3V 63 0

    Equat.    Gal    SGal    Ecl

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2021.04.16-11:12:45

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