2014ApJ...790...47I


Query : 2014ApJ...790...47I

2014ApJ...790...47I - Astrophys. J., 790, 47 (2014/July-3)

The evolution of accretion in young stellar objects: strong accretors at 3-10 myr.

INGLEBY L., CALVET N., HERNANDEZ J., HARTMANN L., BRICENO C., MILLER J., ESPAILLAT C. and McCLURE M.

Abstract (from CDS):

While the rate of accretion onto T Tauri stars is predicted to decline with age, objects with strong accretion have been detected at ages of up to 10 Myr. We analyze a sample of these old accretors, identified by having a significant U band excess and infrared emission from a circumstellar disk. Objects were selected from the ∼3 Myr σ Ori, 4-6 Myr Orion OB1b, and 7-10 Myr Orion OB1a star forming associations. We use high-resolution spectra from the Magellan Inamori Kyocera Echelle to estimate the veiling of absorption lines and calculate extinction for our T Tauri sample. We also use observations obtained with the Magellan Echellette and, in a few cases, the SWIFT Ultraviolet and Optical Telescope to estimate the excess produced in the accretion shock, which is then fit with accretion shock models to estimate the accretion rate. We find that even objects as old as 10 Myr may have high accretion rates, up to ∼10–8 M☉/yr. These objects cannot be explained by viscous evolution models, which would deplete the disk in shorter timescales unless the initial disk mass is very high, a situation that is unstable. We show that the infrared spectral energy distribution of one object, CVSO 206, does not reveal evidence of significant dust evolution, which would be expected during the 10 Myr lifetime. We compare this object to predictions from photoevaporation and planet formation models and suggest that neither of these processes have had a strong impact on the disk of CVSO 206.

Abstract Copyright: ∼

Journal keyword(s): accretion, accretion disks - circumstellar matter - stars: pre-main sequence

Simbad objects: 29

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Number of rows : 29
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026
#notes
1 NAME Taurus Complex SFR 04 41.0 +25 52           ~ 4971 0
2 HD 29647 * 04 41 08.0448698568 +25 59 33.949206132 9.69 9.22 8.31 7.35 6.60 B9IIIpHgMn 217 0
3 Kiso A-0903 109 TT* 05 24 41.0392447800 +01 54 38.530936260     14.93   13.39 K5 34 0
4 * psi01 Ori Be* 05 24 44.8273848312 +01 50 47.201915688 3.83 4.76 4.96 5.04 5.26 B1Vn 372 0
5 NAME 25 Ori Group OpC 05 24 50.9 +01 41 38           ~ 195 1
6 CVSO 224 TT* 05 25 46.7561581056 +01 43 30.291265200     17.21 16.19 14.61 M3.5Ve 38 0
7 CVSO 888 TT* 05 26 46.8233637864 +02 26 03.923893500     13.92     M0e 24 0
8 Kiso A-0903 134 Y*O 05 26 55.3747781472 +01 40 22.400483700   16.40 15.56 15.99 14.82 ~ 31 0
9 Kiso A-0903 176 TT* 05 29 23.2624377048 -01 25 15.450602844     14.79   13.27 K7 51 0
10 Kiso A-0904 1 TT* 05 31 20.6291174208 -00 49 19.847243748     14.72   13.37 K7 38 0
11 Kiso A-0904 4 TT* 05 32 25.7812188960 -00 36 53.368167024     14.65   12.82 K7 42 0
12 Haro 5-66 TT* 05 32 32.6499109067 -01 13 45.834165548     13.89   12.27 M0 42 0
13 Ass Ori OB 1b As* 05 34.0 -01 30           ~ 281 0
14 CVSO 127 TT* 05 34 05.3557722072 -00 47 17.185220412     13.57   12.00 K7 15 0
15 NAME Ori A MoC 05 38 -07.1           ~ 3187 0
16 Haro 5-9 TT* 05 38 29.1605610504 -02 16 15.770920332   15.40 14.45 13.20 12.954 K6.5 38 0
17 NAME sig Ori Cluster OpC 05 38 42 -02 36.0           ~ 623 0
18 * 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) 855 0
19 V* RU Ori TT* 05 38 52.0091406720 -02 46 43.719992436     14.27 13.44 12.72 K7.5 44 0
20 V* BG Ori TT* 05 39 25.2030748440 -02 38 22.059069252   15.88 14.72 13.78 12.83 K7.5 49 0
21 CVSO 173 TT* 05 39 45.6466479288 -00 35 57.243031908     13.71   12.11 K7 6 0
22 NAME Ori B MoC 05 41 43.0 -01 54 44           ~ 1498 0
23 V* FU Ori Or* 05 45 22.3647842544 +09 04 12.291320064   10.72 9.60     F0Iab 888 1
24 * eta Cha Pu* 08 41 19.5125857944 -78 57 48.105898056 5.02 5.351 5.453     B8V 246 0
25 NAME TW Hya Association As* 11 01.9 -34 42           ~ 1018 0
26 NAME Cha 1 MoC 11 06 48 -77 18.0           ~ 1266 1
27 HJM E 1-7 Or* 11 11 34.7528117136 -76 36 21.247478892   16.35 14.73   12.35 K8Ve 42 0
28 V* MN Lup TT* 15 23 30.3994838448 -38 21 28.841024628     14.15     M0 27 0
29 Ass Ori OB 1a As* ~ ~           ~ 237 0

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