2004A&A...424..857C


C.D.S. - SIMBAD4 rel 1.7 - 2019.12.12CET09:32:25

2004A&A...424..857C - Astronomy and Astrophysics, volume 424, 857-872 (2004/9-4)

Photometric variability of young brown dwarfs in the σ Orionis open cluster.

CABALLERO J.A., BEJAR V.J.S., REBOLO R. and ZAPATERO OSORIO M.R.

Abstract (from CDS):

We have carried out multi-epoch, time-series differential I-band photometry of a large sample of objects in the south-east region of the young (∼3Myr), nearby (∼350pc) σ Orionis open cluster. A field of ∼1000arcmin2 was monitored during four nights over a period of two years. Using this dataset, we have studied the photometric variability of twenty-eight brown dwarf cluster candidates with masses ranging from the stellar-substellar boundary down to the planetary-mass domain. We have found that about 50% of the sample show photometric variability on timescales from less than one hour to several days and years. The amplitudes of the I-band light curves range from less than 0.01 up to ∼0.4mag. A correlation between the near-infrared excess in the Ks band, strong Hα emission and large-amplitude photometric variation is observed. We briefly discuss how these results may fit the different scenarios proposed to explain the variability of cool and ultracool dwarfs (i.e. magnetic spots, patchy obscuration by dust clouds, surrounding accretion discs and binarity). Additionally, we have determined tentative rotational periods in the range 3 to 40h for three objects with masses around 60MJup, and the rotational velocity of 14±4km/s for one of them.

Abstract Copyright:

Journal keyword(s): stars: low mass, brown dwarfs - Galaxy: open clusters and associations: individual: σ Orionis - techniques: photometric

Simbad objects: 34

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Number of rows : 34

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 2MASS J05381462-0240154 BD* 05 38 14.624 -02 40 15.40         20.53 L1.5 28 1
2 2MASS J05381741-0240242 BD* 05 38 17.4137148747 -02 40 24.281223771   23.24   19.21 17.09 M5/7V 24 0
3 [BZR99] S Ori 31 Y*O 05 38 20.8779121749 -02 46 13.330061031         17.25 M4.0 23 0
4 [BZR99] S Ori 53 Y*? 05 38 25.120 -02 48 03.08         20.99 ~ 13 0
5 V* V2728 Ori Or* 05 38 25.4362816834 -02 42 41.261836830   20.88 20.33 19.08 17.20 M7 30 0
6 [BZR99] S Ori 45 Or* 05 38 25.578 -02 48 37.02   21.09 24.40 22.07 19.54 M8.5 31 0
7 2MASS J05382623-0240413 Y*O 05 38 26.2366116920 -02 40 41.404641626   21.25 20.45 19.08 16.99 M4.5 17 0
8 Mayrit 803197 Y*O 05 38 28.969 -02 48 47.32   25.83 20.83   17.01 M6 17 0
9 NAME sigma Orionis Cluster MGr 05 38 42 -02 36.0           ~ 475 0
10 * sig Ori Y*O 05 38 44.7665260139 -02 36 00.284709290 2.54 3.58 3.79 3.87 4.11 O9.5V 731 0
11 Mayrit 1316178 Y*? 05 38 47.1459143424 -02 57 55.741623443   19.50 21.15   16.83 ~ 11 0
12 [BMZ2001] S Ori J053849.5-024934 Y*? 05 38 49.578 -02 49 33.25         20.19 M8.75 7 0
13 [BMZ2001] S Ori J053858.6-025228 BD* 05 38 58.55 -02 52 26.6         22.17 L2 7 0
14 [BMZ2001] S Ori J053900.2-023706 Y*? 05 39 00.2 -02 37 06           M8 22 1
15 2MASS J05390193-0235029 Y*O 05 39 01.9389175758 -02 35 02.903447076 19.818 20.72 19.68 18.46 17.11 M4 21 0
16 [BZR99] S Ori 51 Y*? 05 39 03.21 -02 30 19.9         20.32 L0 17 0
17 [BZR99] S Ori 25 Or* 05 39 08.9501208834 -02 39 57.988185282     21.09 19.34 17.02 M6.5V 23 0
18 [BZR99] S Ori 50 Y*? 05 39 10.80 -02 37 14.6         20.52 ~ 11 0
19 [BZR99] S Ori 30 Y*O 05 39 13.0851935602 -02 37 50.971219000     20.74 19.34 17.30 M6 18 0
20 [BZR99] S Ori 16 Y*O 05 39 15.1023993560 -02 40 47.648211886 20.73 21.97   18.73 16.74 M3.5 14 0
21 [BMZ2001] S Ori J053918.1-025257 Y*? 05 39 18.1313272557 -02 52 56.504354682   21.56   21.03 18.89 ~ 7 0
22 [HHM2007] 1013 Y*O 05 39 22.2517713667 -02 45 52.454147942         17.15 ~ 10 0
23 [BZR99] S Ori 28 Y*? 05 39 23.1930476028 -02 46 55.769581456   22.63 21.06 19.41 17.23 M5.5 20 0
24 [BZR99] S Ori 42 Y*? 05 39 23.411 -02 40 57.55         19.18 M7.5 10 0
25 [BZR99] S Ori 36 Y*O 05 39 26.8586946306 -02 36 56.238203362   22.73     17.88 ~ 16 0
26 [BMZ2001] S Ori J053929.4-024636 Y*? 05 39 29.37 -02 46 36.7         19.81 ~ 6 0
27 [BZR99] S Ori 32 Y*? 05 39 43.5830871341 -02 47 31.811439136   21.35   19.75 17.59 ~ 16 0
28 [BMZ2001] S Ori J053944.5-025959 Y*? 05 39 44.53 -02 59 59.0         20.75 ~ 5 0
29 Mayrit 1045094 Y*O 05 39 54.3226122744 -02 37 18.966776375   20.61 20.81 19.05 17.05 M4.5 17 0
30 [BMZ2001] S Ori J053956.8-025315 Y*? 05 39 56.83 -02 53 14.6         21.35 M8 8 0
31 2MASS J05400014-0251594 Y*O 05 40 00.1465539404 -02 51 59.528170369   23.33 20.32 18.61 16.42 ~ 10 0
32 Mayrit 1196092 Y*O 05 40 04.5326197819 -02 36 42.091189449   20.69   19.94 17.73 M6 21 0
33 [BZR2011] S Ori J054006.96-023605.0 Y*? 05 40 06.96 -02 36 05.0         21.44 ~ 5 0
34 V* V2754 Ori Or* 05 40 13.9615344987 -02 31 27.418997878   22.50     17.35 ~ 11 0

    Equat.    Gal    SGal    Ecl

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2019.12.12-09:32:25

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