2001ApJ...556..830B


Query : 2001ApJ...556..830B

2001ApJ...556..830B - Astrophys. J., 556, 830-836 (2001/August-1)

The substellar mass function in σ Orionis.

BEJAR V.J.S., MARTIN E.L., ZAPATERO OSORIO M.R., REBOLO R., BARRADO Y NAVASCUES D., BAILER-JONES C.A.L., MUNDT R., BARAFFE I., CHABRIER G. and ALLARD F.

Abstract (from CDS):

We combine results from imaging searches for substellar objects in the σ Orionis cluster and follow-up photometric and spectroscopic observations to derive a census of the brown dwarf population in a region of 847 arcmin2. We identify 64 very low mass cluster member candidates in this region. We have available three-color (I, Z, and J) photometry for all of them, spectra for 24 objects, and K photometry for 27% of our sample. These data provide a well-defined sequence in the I versus I-J and I versus I-K color-magnitude diagrams and indicate that the cluster exhibits little reddening despite its young age (∼5 Myr). Using state-of-the-art evolutionary models, we derive a mass function from the low-mass stars (0.2 M) across the complete brown dwarf domain (0.075 to 0.013 M) and into the realm of free-floating planetary-mass objects (≤0.013 M). We find that the mass spectrum (dN/dm)∝m–α increases toward lower masses, with an exponent α=0.8±0.4. Our results suggest that planetary-mass isolated objects could be as common as brown dwarfs; both kinds of objects together would be as numerous as stars in the cluster. If the distribution of stellar and substellar masses in σ Orionis is representative of the Galactic disk, older and much lower luminosity free-floating planetary-mass objects with masses down to about 0.005 M should be abundant in the solar vicinity, with a density similar to M-type stars.

Abstract Copyright:

Journal keyword(s): Galaxy: Open Clusters and Associations: Individual: Name: sigma Orionis - Stars: Low-Mass, Brown Dwarfs - Stars: Luminosity Function, Mass Function - Stars: Pre-Main-Sequence

Nomenclature: Table 1: [BMZ2001] S Ori JHHMMSS.s+DDMMSS N=78

CDS comments: CHABRIER C. misprint for CHABRIER G.

Simbad objects: 73

goto Full paper

goto View the references in ADS

Number of rows : 73
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 Cl Melotte 22 OpC 03 46 24 +24 06.8           ~ 3195 0
2 Ass Ori OB 1b As* 05 34.0 -01 30           ~ 254 0
3 UGCS J053636.31-024625.2 * 05 36 36.31 -02 46 25.3         20.67 M9.2 3 0
4 [BMZ2001] S Ori J053653.3-022414 * 05 36 53.3 -02 24 14         23.13 ~ 4 0
5 [BZR99] S Ori 33 * 05 36 58.0796129568 -02 35 19.475262024         17.08 ~ 11 0
6 UGCS J053710.06-024301.3 * 05 37 10.06 -02 43 01.4         19.96 M8.2 4 0
7 [BZR99] S Ori 19 * 05 37 21.0603854496 -02 25 40.035311436         16.62 ~ 6 0
8 [BZR99] S Ori 66 BD* 05 37 24.71064 -02 31 52.3308         23.23 L3.5:e 12 0
9 [BZR99] S Ori 55 LM* 05 37 25.88208 -02 34 32.0736         21.07 M9Ve 22 0
10 [BZR99] S Ori 40 Y*O 05 37 36.4816663032 -02 41 56.713683516   23.22   20.12 17.79 M3.5 18 0
11 [BMZ2001] S Ori J053746.6-024328 * 05 37 46.6 -02 43 28           ~ 2 0
12 [BZR99] S Ori 23 Y*O 05 37 51.1108853952 -02 26 07.501486812   20.6   19.4 16.88 M6.5 14 0
13 [BZR99] S Ori 35 Y*O 05 37 55.5938374392 -02 33 05.343313356 20.472 23.63   19.40 17.55 M4.5 14 0
14 [BZR99] S Ori 24 Y*O 05 37 55.7464490520 -02 24 33.705030096   23.05 20.54 18.89 17.04 M5.0 10 0
15 [BZR99] S Ori 12 Y*O 05 37 57.4587695400 -02 38 44.468902788   20.61 19.81 18.15 16.42 M4.5/6V 25 0
16 [BZR99] S Ori 67 BD* 05 38 12.61464 -02 21 36.7956         23.40 L5:e 9 0
17 [BZR99] S Ori 13 Y*O 05 38 13.2091054320 -02 24 07.556361588   21.07 19.68 18.06 16.13 M5.5 14 0
18 [BZR99] S Ori 47 BD* 05 38 14.62416 -02 40 15.4020         20.53 L1e 28 0
19 V* V2723 Ori Or* 05 38 17.1808248144 -02 22 25.719885012   22.96 19.21 17.61 15.67 M5.0 16 0
20 2MASS J05381741-0240242 BD* 05 38 17.4145740552 -02 40 24.296790180   23.24   19.21 17.09 M5/7V 24 0
21 [BZR99] S Ori 31 Y*O 05 38 20.8792849368 -02 46 13.332049824         17.25 M4.0 23 0
22 Mayrit 379292 Y*O 05 38 21.3850973592 -02 33 36.302074596     20.78 19.47 17.45 ~ 16 0
23 [BZR99] S Ori 53 LM* 05 38 25.11744 -02 48 02.7720         20.99 M9V 13 0
24 V* V2729 Ori Or* 05 38 25.57752 -02 48 37.0224   21.09 24.40 22.07 19.54 M8.5 31 0
25 [BZR99] S Ori 18 Y*O 05 38 25.6854086976 -02 31 21.716183784     19.99 18.68 16.59 M3.5 16 0
26 [BZR99] S Ori 65 BD* 05 38 26.1 -02 23 05         23.23 L3.5: 10 0
27 Mayrit 803197 Y*O 05 38 28.969 -02 48 47.32   25.83 20.83   17.01 M6 17 0
28 [BZR99] S Ori 29 Or* 05 38 29.6185929264 -02 25 14.270648484   21.05 20.72 19.02 17.02 M4.0 19 0
29 [BZR99] S Ori 39 Y*O 05 38 32.4445347456 -02 29 57.296432760 21.027 22.98   19.77 17.71 M6.5 16 0
30 [BZR99] S Ori 54 LM* 05 38 33.33648 -02 20 59.4060           M9.5Ve 11 0
31 [BZR99] S Ori 22 Y*O 05 38 35.3557024968 -02 25 22.268716356   22.52 20.73 18.91 16.87 M6e 17 0
32 [BZR99] S Ori 68 BD* 05 38 39.1 -02 28 05         23.77 L5: 24 1
33 NAME sigma Orionis Cluster MGr 05 38 42 -02 36.0           ~ 524 0
34 * 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) 775 0
35 [BZR99] S Ori 6 Y*O 05 38 47.6632499544 -02 30 37.481740308 20.977 20.25   17.30 15.38 ~ 18 0
36 [BZR99] S Ori 15 Y*O 05 38 48.0991320696 -02 28 53.682649428 21.11 21.32 19.89 18.32 16.42 M5.5e 18 0
37 V* V2737 Ori Or* 05 38 49.2830405880 -02 23 57.624853740 22.321 23.90 19.39 17.67 16.90 M3.8V 22 0
38 [BZR99] S Ori 61 BD* 05 38 52.69032 -02 28 43.9032         22.78 L0: 4 0
39 [BZR99] S Ori 56 BD* 05 39 00.78768 -02 21 41.8032         21.80 L0.5 13 0
40 [BZR99] S Ori 51 LM* 05 39 03.20592 -02 30 19.9440         20.32 M9Ve 17 0
41 [BZR99] S Ori 58 BD* 05 39 03.59736 -02 25 36.6060         21.50 L0e 13 0
42 [BZR99] S Ori 17 Y*O 05 39 04.4949780000 -02 38 35.381301036     20.00 18.92 16.80 M6 16 0
43 [BZR99] S Ori 20 Y*O 05 39 07.5827704608 -02 29 05.658266004   22.49   19.02 17.03 M5.5 16 0
44 2MASS J05390808-0228447 Y*O 05 39 08.086 -02 28 44.77 19.34 19.57 18.69 17.56 15.88 M4.0 16 0
45 [BZR99] S Ori 7 Y*O 05 39 08.2185362880 -02 32 28.467592548 20.85 20.61 19.10 17.55 15.70 ~ 16 0
46 [BZR99] S Ori 25 Or* 05 39 08.9497481544 -02 39 57.986417520     21.09 19.34 17.02 M6.5V 23 0
47 [KJN2005] 33 Y*O 05 39 10.0137047592 -02 28 11.596588608 21.26 20.55 19.01 17.71 16.10 M5 13 0
48 [BZR99] S Ori 50 LM* 05 39 10.80408 -02 37 14.5884         20.52 M9V 11 0
49 Mayrit 425070 Y*O 05 39 11.4017533992 -02 33 32.831052984 21.773 21.52 19.94 18.32 16.43 M5e 26 0
50 2MASS J05391183-0227409 Y*O 05 39 11.8349306400 -02 27 41.009358564 20.843 19.55 18.04 16.81 15.16 ~ 17 0
51 2MASS J05391289-0224537 Y*? 05 39 12.8832672840 -02 24 53.463700008   22.75   21.04 18.94 M6 7 0
52 [BZR99] S Ori 30 Y*O 05 39 13.0855893696 -02 37 50.971269108     20.74 19.34 17.30 M6 18 0
53 [BZR99] S Ori 16 Y*O 05 39 15.1041343392 -02 40 47.667633204 20.73 21.97   18.73 16.74 M3.5 14 0
54 [BZR99] S Ori 38 Y*O 05 39 15.2611041000 -02 21 50.711830596   22.96   20.02 17.97 M7 13 0
55 [BZR99] S Ori 26 * 05 39 15.765 -02 38 26.22         17.12 M4.5 7 0
56 [BMZ2001] S Ori J053918.1-022855 Y*? 05 39 18.1 -02 28 55         23.89 ~ 11 0
57 2MASS J05392023-0238258 Y*O 05 39 20.2371430800 -02 38 25.948061736 21.41 20.82 18.97 17.45 15.55 M5.5 20 0
58 [BZR99] S Ori 3 LM* 05 39 20.9751873360 -02 30 33.534650772   20.66 19.25 17.58 15.57 ~ 19 0
59 [BZR99] S Ori 28 Y*? 05 39 23.1926611128 -02 46 55.782192540   22.63 21.06 19.41 17.23 M5.5 21 0
60 [BMZ2001] S Ori J053926.8-022614 * 05 39 26.7727217568 -02 26 14.336925828   21.76     18.26 ~ 9 0
61 [BZR99] S Ori 36 Y*O 05 39 26.8571235120 -02 36 56.236094820   22.73     17.88 ~ 16 0
62 [BZR99] S Ori 21 Y*O 05 39 34.3303193088 -02 38 46.937656932   21.01 21.12 19.27 17.29 ~ 17 0
63 [BMZ2001] S Ori J053936.4-023626 * 05 39 36.4 -02 36 26           ~ 2 0
64 [BZR99] S Ori 60 BD* 05 39 37.51848 -02 30 41.9220         22.75 L2 18 0
65 [BZR99] S Ori 4 Y*O 05 39 39.3176659728 -02 32 25.331200404 20.429 20.35 18.78 17.34 15.52 ~ 15 0
66 [BZR99] S Ori 62 BD* 05 39 42.05208 -02 30 31.6080         23.03 L2:e 12 0
67 [BZR99] S Ori 32 Y*? 05 39 43.5829405200 -02 47 31.827482016   21.35   19.75 17.59 M6.0 17 0
68 [BZR99] S Ori 11 Y*O 05 39 44.3302873224 -02 33 02.834542764 21.137 20.75 20.11   16.46 M6 15 0
69 [BZR99] S Ori 10 Y*O 05 39 44.5055544576 -02 24 43.244819676   23.03 19.76   16.36 ~ 16 0
70 [BMZ2001] S Ori J053946.5-022423 Y*? 05 39 46.453 -02 24 23.06   21.84 23.60   19.74 ~ 7 0
71 [BMZ2001] S Ori J053947.0-022525 * 05 39 47.0 -02 25 25         21.87 ~ 5 0
72 [SE2004] 108 * 05 39 48.2648127648 -02 29 14.299216584   25.91   20.78 18.68 M7 12 0
73 UGCS J054009.31-022632.6 BD* 05 40 09.32 -02 26 32.6         20.55 L0 9 0

To bookmark this query, right click on this link: simbad:objects in 2001ApJ...556..830B and select 'bookmark this link' or equivalent in the popup menu


2022.07.05-07:49:40

© Université de Strasbourg/CNRS

    • Contact