2007MNRAS.381.1077R


C.D.S. - SIMBAD4 rel 1.7 - 2020.03.28CET22:34:08

2007MNRAS.381.1077R - Mon. Not. R. Astron. Soc., 381, 1077-1092 (2007/November-1)

An optical spectroscopic HR diagram for low-mass stars and brown dwarfs in Orion.

RIDDICK F.C., ROCHE P.F. and LUCAS P.W.

Abstract (from CDS):

The masses and temperatures of young low-mass stars and brown dwarfs in star-forming regions are not yet well established because of uncertainties in the age of individual objects and the spectral type-temperature scale appropriate for objects with ages of only a few Myr. Using multi-object optical spectroscopy, 45 low-mass stars and brown dwarfs in the Trapezium Cluster in Orion have been classified and 44 of these confirmed as bona fide cluster members. The spectral types obtained have been converted to effective temperatures using a temperature scale intermediate between those of dwarfs and giants, which is suitable for young pre-main-sequence objects. The objects have been placed on a Hertzsprung-Russell (HR) diagram overlaid with theoretical isochrones. The low-mass stars and the higher mass substellar objects are found to be clustered around the 1 Myr isochrone, while many of the lower mass substellar objects are located well above this isochrone. An average age of 1 Myr is found for the majority of the objects. Assuming coevality of the sources and an average age of 1 Myr, the masses of the objects have been estimated and range from 0.018 to 0.44M. The spectra also allow an investigation of the surface gravity of the objects by measurement of the sodium doublet equivalent width. With one possible exception, all objects have low gravities, in line with young ages, and the Na indices for the Trapezium objects lie systematically below those of young stars and brown dwarfs in Chamaeleon, suggesting that the 820 nm Na index may provide a sensitive means of estimating ages in young clusters.

Abstract Copyright: 2007 The Authors. Journal compilation © 2007 RAS

Journal keyword(s): stars: formation - Hertzsprung-Russell (HR) diagram - stars: low-mass, brown dwarfs - stars: pre-main-sequence

Nomenclature: Tables 2,3: [RRL2007] SSs-MSS, [RRL2007] MSSs-MSS, N=45+11.

Status at CDS:  

Simbad objects: 74

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Number of rows : 74

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 IC 348 OpC 03 44 34 +32 09.8           ~ 1215 1
2 HZ 2 WD* 04 12 43.5549840231 +11 51 48.973557049 12.903 13.787 13.877 13.984 14.094 DA2.3 90 0
3 2MASS J05345590-0521084 * 05 34 55.9027524876 -05 21 08.551681710         18.043 M6.25 9 0
4 2MASS J05345694-0521219 Y*O 05 34 56.9515706844 -05 21 21.883007939         17.029 M6.75 11 0
5 [RRL2007] 4584-117 * 05 34 58.48 -05 21 17.7           ~ 2 0
6 NAME Orion Nebula Cluster OpC 05 35.0 -05 29           ~ 1941 1
7 [OW94] 011-029 * 05 35 01.1 -05 20 29           ~ 2 0
8 [OW94] 014-413 Ir* 05 35 01.3635074134 -05 24 13.324482683     18.21 17.76 17.677 M6.5 14 0
9 2MASS J05350158-0525339 Y*O 05 35 01.5821751332 -05 25 33.984864439   19.898 18.988 16.94 15.160 M5 26 0
10 V* V2114 Ori Or* 05 35 01.6680335527 -05 26 36.302338182   20.687 19.948 17.78 16.296 M3e 18 1
11 [LRT2005] 36 * 05 35 01.7 -05 27 10           ~ 1 0
12 [MRD2012] 201 Ir* 05 35 01.8715802623 -05 23 53.704234306         17.168 M5.75 11 0
13 [LRT2005] 030-524 * 05 35 02.996 -05 25 24.26           M7.5 5 0
14 2MASS J05350313-0525364 * 05 35 03.131 -05 25 36.47           M8.75 5 0
15 2MASS J05350343-0526100 Y*O 05 35 03.4329342563 -05 26 10.054215602   15.5 19.577 16.87 15.596 M4.5 23 0
16 2MASS J05350344-0523327 Y*O 05 35 03.4434505441 -05 23 32.816528676   15.9 19.693   16.066 M3.5e 20 0
17 2MASS J05350370-0522457 Y*O 05 35 03.7012532516 -05 22 45.726832758         16.209 M5.5e 24 0
18 [H97b] 20301 * 05 35 04.09 -05 22 09.7         20.000 M3.75 3 0
19 [H97b] 10364 V* 05 35 04.1901227681 -05 20 12.328080600         17.133 M7.75 12 0
20 2MASS J05350444-0522194 * 05 35 04.441 -05 22 19.46         19.615 M7.5 6 1
21 [LRT2005] 342 * 05 35 04.6 -05 22 45           M 2 0
22 V* V2142 Ori Or* 05 35 04.6964084762 -05 24 35.930282336         16.575 M 17 0
23 [LRT2005] 143 * 05 35 04.7 -05 25 50           ~ 1 0
24 [RRL2007] 050-143 * 05 35 04.95 -05 21 42.8         19.267 M 3 0
25 [LRT2005] 208 Ir* 05 35 05.2927279848 -05 25 02.992106054     17.15 16.76 16.721 M4.5 15 0
26 V* V2154 Ori Or* 05 35 05.4556085781 -05 22 30.524626233         16.344 M6.5 27 0
27 2MASS J05350678-0520190 Y*O 05 35 06.7841616362 -05 20 19.028165981   15.9     16.382 M5.5 19 0
28 COUP 276 * 05 35 06.8893478638 -05 22 09.226715579   15.3     15.723 M6 25 0
29 [LRT2005] 70 * 05 35 07.3 -05 26 37           ~ 1 0
30 [RRL2007] 077-127 * 05 35 07.7 -05 21 27           ~ 1 0
31 [MRD2012] 258 Ir* 05 35 07.7083700138 -05 24 52.828404553   14.3 16.23 15.66 15.528 M4 24 0
32 2MASS J05350821-0522532 * 05 35 08.216 -05 22 53.23           M7-M8 8 0
33 2MASS J05350822-0524032 Y*O 05 35 08.2402000707 -05 24 03.174194915   14.2     15.508 M4.5 25 0
34 V* V2183 Ori Or* 05 35 08.42 -05 21 19.9         17.826 M? 14 0
35 2MASS J05350843-0523049 Y*O 05 35 08.4359205322 -05 23 04.959282730         17.040 M7 16 0
36 MLLA 390 * 05 35 08.60 -05 23 24.2         18.145 M5.5: 8 0
37 [MRD2012] 2420 V* 05 35 09.0530362741 -05 20 17.173426088   15.6     15.947 M4 19 0
38 MLLA 5 * 05 35 09.20 -05 26 05.5         20.074 M8 5 0
39 [MRD2012] 2414 V* 05 35 09.4765372252 -05 20 58.698865798   15.0     15.612 M6 24 0
40 2MASS J05350957-0519426 Y*O 05 35 09.5705438027 -05 19 42.654564968         17.783 M6.5 11 0
41 [RRL2007] 102-102 * 05 35 10.2 -05 21 02           ~ 1 0
42 2MASS J05351026-0521571 Y*O 05 35 10.2622087981 -05 21 57.119969605   13.9     15.171 M5.5 23 0
43 [AD95] 3374 Ir* 05 35 11.1573736633 -05 25 32.286055432         16.141 M5 18 0
44 [RRL2007] 117-609 * 05 35 11.7 -05 26 09           M 1 0
45 V* V2224 Ori Or* 05 35 12.130 -05 24 33.82   13.8 15.19 14.66 15.940 M8.25 27 0
46 COUP 512 * 05 35 12.93 -05 24 57.6         17.137 M5.25 10 0
47 [RRL2007] 130-053 * 05 35 13.0 -05 20 56           ~ 2 0
48 [RRL2007] 139-425 * 05 35 13.9 -05 24 25           M 1 0
49 NAME OMC-1 MoC 05 35 14 -05 22.4           ~ 1003 2
50 NAME Orion-KL SFR 05 35 14.16 -05 22 21.5           ~ 1976 1
51 2MASS J05351475-0528318 BD* 05 35 14.756 -05 28 31.81         21.004 M8.5 4 0
52 [RRL2007] 148-831 * 05 35 14.8 -05 28 31           ~ 1 0
53 [LRT2005] 132 * 05 35 15.4 -05 26 00           ~ 2 0
54 [LRT2005] 149 * 05 35 15.6 -05 25 47           ~ 1 0
55 [RRL2007] 160-607 * 05 35 16.0 -05 26 07           M 1 0
56 [LRT2005] 82 * 05 35 16.5 -05 26 34           ~ 1 0
57 NAME Trapezium Cluster As* 05 35 16.5 -05 23 14           ~ 1448 1
58 M 42 HII 05 35 17.3 -05 23 28           ~ 3693 0
59 [LRT2005] 154 * 05 35 17.7 -05 25 40           ~ 1 0
60 [RRL2007] 183-729 * 05 35 18.3 -05 27 29           ~ 1 0
61 2MASS J05351862-0526313 * 05 35 18.63 -05 26 31.4         18.544 M8 6 0
62 [OW94] 196-659 * 05 35 19.6 -05 27 00           M 3 0
63 [MRD2012] 882 V* 05 35 21.6917648474 -05 26 52.614831753     17.60 15.79 17.031 M7.75 10 0
64 COUP 1203 * 05 35 22.1758927619 -05 27 44.811682969     19.33 19.82 17.520 M5.75 10 0
65 NAME Orion Bright Bar reg 05 35 22.30 -05 24 33.0           ~ 706 0
66 V* RR Tau Ae* 05 39 30.5114685049 +26 22 26.961204895 11.64 12.09 11.28 10.58 10.17 A0:IVe 216 0
67 NGC 2024 Cl* 05 41 43 -01 50.5           ~ 1063 1
68 GD 71 WD* 05 52 27.6197286025 +15 53 13.228639956 11.675 12.783 13.032 13.169 13.337 DA1.5 331 0
69 HD 84937 PM* 09 48 56.09801 +13 44 39.3237 8.49 8.68 8.32 7.97 7.70 F8Vm-5 715 0
70 Feige 34 HS* 10 39 36.7377085527 +43 06 09.209752646 9.613 10.91 11.14 11.319 11.464 sdOp 599 0
71 NAME Cha I MoC 11 06 48 -77 18.0           ~ 949 1
72 NAME Cha Dark Cloud SFR 11 55 -78.0           ~ 543 1
73 NAME Ophiuchus Molecular Cloud SFR 16 28 06 -24 32.5           ~ 2979 0
74 NAME eps Ori Cluster Cl* ~ ~           ~ 19 1

    Equat.    Gal    SGal    Ecl

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2020.03.28-22:34:08

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