2017A&A...602A..10G


Query : 2017A&A...602A..10G

2017A&A...602A..10G - Astronomy and Astrophysics, volume 602A, 10-10 (2017/6-1)

CSI 2264: Simultaneous optical and X-ray variability in pre-main sequence stars. I. Time resolved X-ray spectral analysis during optical dips and accretion bursts in stars with disks.

GUARCELLO M.G., FLACCOMIO E., MICELA G., ARGIROFFI C., SCIORTINO S., VENUTI L., STAUFFER J., REBULL L. and CODY A.M.

Abstract (from CDS):

Context. Pre-main sequence stars are variable sources. The main mechanisms responsible for their variability are variable extinction, unsteady accretion, and rotational modulation of both hot and dark photospheric spots and X-ray-active regions. In stars with disks, this variability is related to the morphology of the inner circumstellar region (≤0.1AU) and that of the photosphere and corona, all impossible to be spatially resolved with present-day techniques. This has been the main motivation for the Coordinated Synoptic Investigation of NGC 2264, a set of simultaneous observations of NGC 2264 with 15 different telescopes.
Aims. In this paper, we focus on the stars with disks. We analyze the X-ray spectral properties extracted during optical bursts and dips in order to unveil the nature of these phenomena. Stars without disks are studied in a companion paper.
Methods. We analyze simultaneous CoRoT and Chandra/ACIS-I observations to search for coherent optical and X-ray flux variability in stars with disks. Then, stars are analyzed in two different samples. In stars with variable extinction, we look for a simultaneous increase of optical extinction and X-ray absorption during the optical dips; in stars with accretion bursts, we search for soft X-ray emission and increasing X-ray absorption during the bursts.
Results. We find evidence for coherent optical and X-ray flux variability among the stars with variable extinction. In 9 of the 24 stars with optical dips, we observe a simultaneous increase of X-ray absorption and optical extinction. In seven dips, it is possible to calculate the NH/AV ratio in order to infer the composition of the obscuring material. In 5 of the 20 stars with optical accretion bursts, we observe increasing soft X-ray emission during the bursts that we associate to the emission of accreting gas. It is not surprising that these properties are not observed in all the stars with dips and bursts, since favorable geometric configurations are required.
Conclusions. The observed variable absorption during the dips is mainly due to dust-free material in accretion streams. In stars with accretion bursts, we observe, on average, a larger soft X-ray spectral component not observed in non-accreting stars.

Abstract Copyright: © ESO, 2017

Journal keyword(s): circumstellar matter - stars: pre-main sequence - stars: rotation - stars: variables: T Tauri, Herbig Ae/Be - stars: variables: T Tauri, Herbig Ae/Be

Simbad objects: 57

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Number of rows : 57
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 IC 348 OpC 03 44 32 +32 09.5           ~ 1334 1
2 V* BP Tau Or* 04 19 15.8339827632 +29 06 26.926959492   13.13 12.12 11.89   K5/7Ve 645 0
3 V* AA Tau Or* 04 34 55.4201902392 +24 28 53.033624580 13.14 13.34 12.20 12.03   K5Ve 698 0
4 NAME Orion Nebula Cluster OpC 05 35.0 -05 29           ~ 2206 1
5 M 42 OpC 05 35 17 -05 23.4           ~ 3970 0
6 NGC 2129 OpC 06 01 06 +23 19.7   7.31 6.7     ~ 108 0
7 V* NV Mon TT* 06 40 37.8654419808 +09 34 54.077163708 18.689 17.913 16.492 15.63 14.293 M3e 43 0
8 V* V338 Mon TT* 06 40 38.1954521520 +09 29 52.502499528 19.44 18.86 17.37 16.38 15.20 M1e 33 0
9 NGC 2264 84 TT* 06 40 42.1820308368 +09 33 37.422060732 12.575 12.57 12.01 11.74 11.33 G0 68 0
10 ESO-HA 399 TT* 06 40 44.5898682264 +09 32 26.171210580   19.65 18.29 17.23 15.61 M3e 28 0
11 EM* LkHA 364 TT* 06 40 45.1638228528 +09 28 44.402128932 15.82 15.25 14.2 13.59 13.03 K2 43 0
12 V* NY Mon TT* 06 40 47.1143763720 +09 32 40.066736352 17.49 17.57 16.33 15.36 14.28 M1V 44 0
13 V* LT Mon TT* 06 40 49.8920296632 +09 36 49.458646872 16.4 16.49 15.42 14.6 13.80 K4 58 0
14 NGC 2264 108 TT* 06 40 51.1854488784 +09 44 46.109300100 12.684 12.42 12.004 11.661 11.35 F8V 70 0
15 EM* LkHA 33 TT* 06 40 51.5429401920 +09 43 24.229130664 16.31 15.69 14.51 13.85 13.22 K4 54 0
16 V* NZ Mon TT* 06 40 51.5889922248 +09 28 44.516455896 17.85 17.32 16.07 15.21 14.37 K4e 46 0
17 NGC 2264 OpC 06 40 52 +09 52.6           ~ 1730 0
18 KHA 98 TT* 06 40 52.9232940792 +09 44 54.384889740 16.892 16.515 15.339 14.893 13.705 K5/6e 40 0
19 EM* LkHA 35 TT* 06 40 53.6366394552 +09 33 24.733235304 16.095 15.43 14.42 14.07 13.386 K1e 65 0
20 V* GQ Mon TT* 06 40 56.1649417464 +09 36 30.900933504   17.083 17.245 15.19 14.06 K3e 43 0
21 V* LU Mon TT* 06 40 56.8048981512 +09 37 49.001244060 16.22 16.21 15.07 14.23 13.39 K5e 65 0
22 V* V603 Mon TT* 06 40 57.8384372520 +09 41 20.164429608 18.21 17.73 16.27 15.27 14.23 M0 39 0
23 * 15 Mon Be* 06 40 58.65963 +09 53 44.7229 3.360 4.45 4.68   4.88 O7V+B1.5/2V 781 0
24 EM* LkHA 42 TT* 06 40 58.6712407104 +09 36 13.288007844   18.43 17.4 15.97 14.29 M4e 33 0
25 KHA 103 TT* 06 40 58.8258827088 +09 39 18.748380528   17.83 17.02 16.01 14.95 M0e 37 0
26 V* IO Mon TT* 06 40 58.836576 +09 30 57.26412   15.30 14.04 13.11 12.49 K2/3e 63 0
27 ESO-HA 447 TT* 06 40 58.9180523112 +09 28 52.923032436   18.325 16.84   14.43 M1e 21 0
28 V* V421 Mon TT* 06 40 59.5468722264 +09 35 10.857042744 18.05 17.18 15.49 14.44 13.31 K4 50 0
29 V* LV Mon TT* 06 40 59.6792286312 +09 28 43.767341760 17.06 17.05 15.9 15.13 14.14 M1 37 0
30 V* V354 Mon TT* 06 41 00.5100986520 +09 29 15.955881864 16.81 15.94 14.73 14.04 13.34 K4e 53 0
31 V* IP Mon TT* 06 41 00.9824167032 +09 32 44.468341836 15.55 14.77 13.48 12.68 11.92 K1 74 0
32 V* LW Mon TT* 06 41 03.3738865968 +09 40 44.985950112 18.07 17.14 15.81 14.97 14.07 M1 41 0
33 ESO-HA 473 TT* 06 41 03.6067060128 +09 30 29.023373196   19.53 17.79 16.55 14.72 M5 36 0
34 V* V607 Mon TT* 06 41 04.0664060184 +09 35 21.068051064 18.99 18.23 16.72 15.67 14.44 M2.5e 39 0
35 V* LY Mon TT* 06 41 04.2833670727 +09 24 52.196452401 16.44 16.324 15.510 15.492 14.10 M0e 49 0
36 Cl* NGC 2264 FMS 345 TT* 06 41 04.5076412616 +09 30 13.443838056   19.45 18.05 16.87 15.42 Me 22 0
37 NGC 2264 162 TT* 06 41 05.7396734232 +09 31 01.201438344 17.59 16.94 15.44 14.58 13.55 K5e 42 0
38 EM* LkHA 53 TT* 06 41 06.1986599352 +09 36 22.927167036 14.71 14.31 13.43 12.9 12.43 G3V 84 1
39 V* V608 Mon TT* 06 41 06.7366834752 +09 34 45.933262572 18.07 17.51 16.24 15.29 14.28 G6: 44 0
40 EM* LkHA 54 TT* 06 41 06.8095737634 +09 27 32.279152952 14.22 14.01 12.97 12.27 11.61 Ge 39 0
41 EM* LkHA 59 TT* 06 41 11.8539957024 +09 26 31.452178452 16.66 16.55 15.15 14.28 13.44 K7e 39 0
42 V* V583 Mon TT* 06 41 13.2977989440 +09 31 50.279006532 19.51 19.3 17.71 16.39 14.61 M4e 38 0
43 Cl* NGC 2264 SBL 2420 TT* 06 41 13.3088244120 +09 51 54.452583072 19.38 18.93 17.35 16.36 15.27 M1e 29 0
44 Cl* NGC 2264 SBL 1025 TT* 06 41 14.75400 +09 34 13.4724   19.24 17.87 16.88 15.61 K8/M0e 29 0
45 EM* LkHA 64 TT* 06 41 15.1141083360 +09 26 44.387646216 18.12 17.93 16.66 15.6 14.48 M0.5e 38 0
46 V* OT Mon TT* 06 41 16.6873099296 +09 29 52.258157520 17.64 17.06 15.7 14.81 13.73 K1 37 0
47 V* MN Mon TT* 06 41 16.7841879888 +09 27 30.211272648 16.38 16.36 15.34 14.59 13.91 K4 48 0
48 V* V821 Mon TT* 06 41 17.9246516280 +09 29 01.159981296   20.23 18.28 16.86 15.29 M2.5 35 0
49 EM* LkHA 68 TT* 06 41 18.2761562688 +09 33 53.577015984 16.3 16.05 14.92 14.18 13.51 K4 57 0
50 EM* LkHA 67 Or* 06 41 18.3745865088 +09 39 41.204991816 17.47 17.53 16.36 15.53 14.57 M1e 45 0
51 V* OV Mon TT* 06 41 21.0106191456 +09 33 36.091832724 16.93 16.43 15.16 14.38 13.56 K6e 56 0
52 ESO-HA 528 SB* 06 41 25.6230226152 +09 34 43.009297284 18.14 17.49 16.03 15.31 14.37 M0 42 0
53 ESO-HA 531 TT* 06 41 26.9964941856 +09 30 13.143888576   19.01 17.5 16.45 15.19 M1e 33 0
54 NGC 2264 213 TT* 06 41 28.7798173944 +09 38 38.946253632 15.61 15.03 14.03 13.46 12.89 K3 43 0
55 NGC 2264 499 TT* 06 41 34.5568639224 +09 36 32.466052692 19.56 18.82 17.33 16.31 15.13 M1 32 0
56 V* TW Hya TT* 11 01 51.9053285064 -34 42 17.033218380   11.94 10.50 10.626 9.18 K6Ve 1787 1
57 HD 319139 SB* 18 14 10.4818675368 -32 47 34.516836060   11.47 10.68   9.11 K5+K7 341 0

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2023.01.27-21:51:45

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