2020A&A...634A.128N


Query : 2020A&A...634A.128N

2020A&A...634A.128N - Astronomy and Astrophysics, volume 634A, 128-128 (2020/2-1)

Sporadic and intense accretion in a 1 Myr-old brown dwarf candidate.

NGUYEN-THANH D., PHAN-BAO N., MURPHY S.J. and BESSELL M.S.

Abstract (from CDS):

Context. Studying the accretion process in very low-mass objects has important implications for understanding their formation mechanism. Many nearby late-M dwarfs that have previously been identified in the field are in fact young brown dwarf members of nearby young associations. Some of them are still accreting. They are therefore excellent targets for further studies of the accretion process in the very low-mass regime at different stages. Aims. We aim to search for accreting young brown dwarf candidates in a sample of 85 nearby late-M dwarfs. Methods. Using photometric data from DENIS, 2MASS, and WISE, we constructed the spectral energy distribution of the late- M dwarfs based on BT-Settl models to detect infrared excesses. We then searched for lithium and Hα emission in candidates that exhibit infrared excesses to confirm their youth and the presence of accretion. Results. Among the 85 late-M dwarfs, only DENIS-P J1538317-103850 (M5.5) shows strong infrared excesses in WISE bands. The detection of lithium absorption in the M5.5 dwarf and its Gaia trigonometric parallax indicate an age of ∼1Myr and a mass of 47MJ. The Hα emission line in the brown dwarf shows significant variability that indicates sporadic accretion. This 1Myr-old brown dwarf also exhibits intense accretion bursts with accretion rates of up to 10–7.9M/yr. Conclusions. Our detection of sporadic accretion in one of the youngest brown dwarfs might imply that sporadic accretion at early stages could play an important role in the formation of brown dwarfs. Very low-mass cores would not be able to accrete enough material to become stars, and thus they end up as brown dwarfs.

Abstract Copyright: © ESO 2020

Journal keyword(s): techniques: spectroscopic - techniques: photometric - brown dwarfs - circumstellar matter - stars: low-mass

CDS comments: Some DENIS objects in fig.A.1 not in SIMBAD.

Simbad objects: 90

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Number of rows : 90
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 NAME THA As* 00 00 -62.0           ~ 424 0
2 LP 584-4 LM* 00 02 06.2174911713 +01 15 36.144258116   20.8   18.4   M6.5e 18 0
3 2MASS J00130931-0025521 LM* 00 13 09.3302143752 -00 25 51.898937016           M6.0V 11 0
4 LP 644-1 PM* 00 13 46.6067843826 -04 57 37.177898186   19.5       M6.5V 12 0
5 2MASS J00192753-3620153 PM* 00 19 27.5473783392 -36 20 15.480037104   18.2       M5.5 4 0
6 LP 825-35 ** 00 20 23.1814766544 -23 46 05.679024132   19.3   17.71   M6e 11 0
7 DENIS J004135.3-562112 LM* 00 41 35.3862348768 -56 21 12.872262132       17.97 14.69 M7.5e 33 0
8 2MASS J01000219-6156270 PM* 01 00 02.2346965632 -61 56 27.198927240           M6 5 0
9 LEHPM 1188 PM* 01 03 12.0009800088 -53 51 43.338127968   20.1       M5.5e 7 0
10 2MUCD 10076 PM* 01 20 49.1702103192 -07 41 03.690808548           M8e 8 0
11 2MASS J01443191-4604318 PM* 01 44 31.9012486056 -46 04 31.819863180   19.3       M5.5e 9 0
12 SIPS J0145-3729 ** 01 45 43.48872 -37 29 59.3268           M7.5e 7 0
13 SIPS J0235-0711 LM* 02 35 49.5920205528 -07 11 21.113473992   21.0   17.78 14.463 M7V 14 0
14 SSSPM J0306-3648 PM* 03 06 11.5989084374 -36 47 52.853856754   20.6 19.2     M8.7V 22 0
15 CPD-69 177 WD* 03 10 31.0195960176 -68 36 03.380768388 10.757 11.413 11.394 11.47 11.558 DA3.0 254 0
16 LSPM J0312+0021 SB* 03 12 25.1052265968 +00 21 58.391730288   20.4   17.0   M7V 16 0
17 LEHPM 3263 PM* 03 20 58.8681763616 -55 20 15.718721836   20.1       M5.5e 10 0
18 2MASS J03242687-7727053 PM* 03 24 26.8565114203 -77 27 05.534567157   20.4       M6e 7 0
19 LP 593-68 LM* 03 51 00.0274722419 -00 52 44.922468108   19.8 18.02     M8.0V 59 0
20 LP 714-37 ** 04 10 48.10248 -12 51 42.1488   18.4   15.0 12.99 M5.5+M8.0+M8.5 24 0
21 LP 890-2 PM* 04 13 39.8287646232 -27 04 29.296774848   22.0       M6V 10 0
22 2MASS J04362788-4114465 PM* 04 36 27.8873100288 -41 14 46.452236496           M8p? 15 0
23 LP 655-48 PM* 04 40 23.2746368923 -05 30 08.125383990   18.9 17.79 15.72 13.36 M7.5Ve 56 0
24 LEHPM 2-183 PM* 05 17 37.6991888127 -33 49 03.090270063   21.1       M8.0V 26 0
25 2MASS J05181131-3101529 LM* 05 18 11.3250403344 -31 01 52.898696364     17.74   14.17 M6.5 11 0
26 LP 836-41 PM* 05 20 29.3722686491 -23 18 48.659026419   19.2       M5e 4 0
27 NAME Columba Association As* 06 04 19.4 -22 20 40           ~ 254 0
28 LP 783-2 PM* 07 40 19.3718248157 -17 24 45.912945536   17.6 16.696 14.695 12.37 M6.5Ve 70 0
29 LAWD 25 WD* 07 40 20.7886676070 -17 24 49.156867583   13.36 13.061 12.886 12.70 DZQA6 193 0
30 WISEA J080822.18-644357.3 * 08 08 22.2107592240 -64 43 57.655480548           M5.5 14 0
31 SCR J0838-5855 PM* 08 38 02.1619253321 -58 55 58.465465641   18.44 17.15 15.08 12.78 M6e 14 0
32 LP 786-41 PM* 08 48 18.9230086582 -20 19 10.962427751   19.7       M6V 11 0
33 LP 788-1 PM* 09 31 22.3161639762 -17 17 42.655397800   19.2     13.140 M6.5 12 0
34 LP 609-24 LM* 10 03 19.1591671629 -01 05 08.000660498   21.0 21.0   14.94 M7e 27 0
35 LP 789-23 PM* 10 06 31.9473645332 -16 53 26.307268882   20.3   16.875 14.573 M7.5Ve 23 0
36 SIPS J1021-2044 LM* 10 21 32.3158144531 -20 44 07.080013158         16.09 M8.5V 8 0
37 LP 610-5 PM* 10 21 51.3179683632 -03 23 09.862497456   20.0   16.810 14.514 M6.5V 11 0
38 LP 731-58 Er* 10 48 12.6142508200 -11 20 09.610693470     15.784 16.01 11.25 M6.5V 156 0
39 LP 731-47 PM* 11 06 56.9100974425 -12 44 02.737571635         14.18 M6e 17 0
40 LP 673-63 PM* 11 36 40.9720986360 -07 55 11.997095556   17.8       M6e 5 0
41 LEHPM 2-333 PM* 11 41 44.0489265526 -22 32 15.010503377           M7.5V 17 0
42 LP 793-34 PM* 11 45 35.3980352256 -20 21 04.904269200   19.0       M5e 7 0
43 LAWD 37 WD* 11 45 42.9169346379 -64 50 29.461957832 11.08 11.725 11.513 11.34 11.163 DQ 248 0
44 LP 613-50 Er* 11 47 42.0964245186 +00 15 06.046553237   18.6   15.5   M5e 18 0
45 LP 851-346 PM* 11 55 42.8518932351 -22 24 58.797393048   19.6     13.203 M7.5V 25 0
46 LP 908-5 PM* 12 01 42.0788865820 -27 37 46.294561613   19.8       M6.5Ve 8 0
47 LP 734-87 ** 12 16 10.12680 -11 26 10.3020           M5.5e 7 0
48 LP 908-68 PM* 12 23 56.1896036746 -27 57 46.495016028   19.6       M6.5V 21 0
49 2MASS J12363959-1722170 PM* 12 36 39.5821806912 -17 22 17.265775908           M6 6 0
50 APMPM J1251-2121 PM* 12 50 52.6489846010 -21 21 13.589571791   21.3 19.0 16.67   M7.5e 22 0
51 LP 911-56 PM* 13 46 46.0467622497 -31 49 25.525439039   18.0     13.165 M6 15 0
52 DENIS J135714.9-143852 LM* 13 57 14.9244255569 -14 38 52.741731766       17.846 15.460 M7.5e 14 0
53 LP 912-49 PM* 14 06 49.3571665466 -30 18 27.992344644   18.5       M5.5Ve 12 0
54 WT 460 ** 14 11 59.8993078070 -41 32 21.916525001   16.0       M5.5e 13 0
55 LP 679-32 PM* 14 12 06.9647345061 -04 13 48.591749185   19.1       M5.5Ve 9 0
56 NAME beta Pic Moving Group MGr 14 30 -42.0           ~ 691 0
57 LP 859-1 LM* 15 04 16.1763702958 -23 55 56.566174303         14.652 M7.5Ve 22 0
58 DENIS J151233.3-103241 LM* 15 12 33.2745450600 -10 32 41.573747004         16.00 M8 5 0
59 DENIS J153831.6-103900 IR 15 38 31.62 -10 39 00.4           ~ 1 0
60 2MASS J15383166-1038507 * 15 38 31.6696868832 -10 38 50.716599252           M5/5.5e 7 0
61 LP 860-30 PM* 15 46 11.5495261325 -25 14 05.305684472   19.0       M5e 5 0
62 LP 860-41 PM* 15 52 44.6116720802 -26 23 13.708406460   17.4       M6.0V 18 0
63 LP 860-46 PM* 15 53 57.0927077485 -23 11 53.322193519           M5.5Ve 14 0
64 LP 684-33 PM* 16 10 58.4298793632 -06 31 32.558184300   18.5       M5.5 9 0
65 NAME Upper Sco Association As* 16 12 -23.4           ~ 1222 1
66 LP 624-54 PM* 16 14 25.1987021529 -02 51 00.750848237   19.3     13.528 M5.0V 13 0
67 LP 626-2 PM* 16 45 28.2011864616 -01 12 28.980428076   20.1       M5.5e 6 0
68 PM J17189-4131 PM* 17 18 54.5503395450 -41 31 40.078732659     15.94     M6 7 0
69 SIPS J1809-7613 PM* 18 09 06.9339662808 -76 13 23.894234364         11.615 M5e 7 0
70 SCR J1855-6914 PM* 18 55 47.8705859255 -69 14 14.929719731     16.61 14.79 12.66 M6e 11 0
71 LP 924-17 PM* 19 17 04.5157626240 -30 19 20.103092364         13.813 M5.5e 6 0
72 LAWD 74 WD* 19 20 34.9229289504 -07 40 00.065957592 11.553 12.345 12.290 12.229 12.164 DBQA5 214 0
73 SIPS J2002-5425 PM* 20 02 13.4442370708 -54 25 55.904903480   18.5   16.9 13.89 M6e 9 0
74 2MASS J20224803-5645567 LM* 20 22 48.0336590880 -56 45 56.781140508           M5.5 6 0
75 LP 816-10 PM* 20 49 52.7324575100 -17 16 08.465962357   18.6   16.93 14.003 M6 14 0
76 SIPS J2107-3357 PM* 21 07 24.7503129138 -33 57 33.593558163   19.9   17.15   M5.5 10 0
77 LP 698-2 PM* 21 32 29.7696606516 -05 11 59.028747425   19.1       M6Ve 19 0
78 WT 792 PM* 21 34 22.2973716749 -43 16 10.640375629   18.0       M5.5 12 0
79 LP 638-50 PM* 21 51 27.0248468832 -01 27 14.307351480   17.9       M5.5Ve 14 0
80 LP 759-17 LM* 22 02 11.2669895232 -11 09 46.364042952   20.7   17.048 14.736 M6/6.5e 21 0
81 LP 759-25 PM* 22 05 35.7339842581 -11 04 28.959853733   18.4   16.4 13.73 M6Ve 30 0
82 2MASSW J2206228-204705 SB* 22 06 22.8297746064 -20 47 06.597790152     19.788 17.452 14.877 M8.0V 44 0
83 WT 887 PM* 22 13 50.4642728880 -63 42 10.010267604           M5/6e 13 0
84 DENIS J222644.3-750342 LM* 22 26 44.4157216320 -75 03 42.533035596         15.21 M8 14 0
85 LEHPM 5031 PM* 22 41 59.3675229576 -75 00 33.059448792           M5.5 6 0
86 APMPM J2331-2750 PM* 23 31 21.7441281210 -27 49 49.608010738   20.4 19.072 16.540 14.190 M7.0V 28 0
87 LP 878-3 PM* 23 33 40.6316955105 -21 33 53.092574857   19.3       M5.0V 15 0
88 LP 763-3 LM* 23 37 38.3459624881 -12 50 28.367211547   18.0   15.795 13.621 M5.5Ve 20 0
89 DENIS J235359.4-083331 PM* 23 53 59.4572638456 -08 33 31.685096490       18.251 15.834 M8.6V 20 0
90 NAME Carina Association As* ~ ~           ~ 139 1

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2022.10.07-04:26:27

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