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 - 2022
#notes
1 IC 348 OpC 03 44 32 +32 09.5           ~ 1274 1
2 V* BP Tau Or* 04 19 15.8342975037 +29 06 26.929456808   13.13 12.12 11.89   K5/7Ve 625 0
3 V* AA Tau Or* 04 34 55.4222683130 +24 28 53.038273587 13.14 13.34 12.20     K5Ve 665 0
4 NAME Orion Nebula Cluster OpC 05 35.0 -05 29           ~ 2091 1
5 M 42 HII 05 35 17.3 -05 23 28           ~ 3853 0
6 NGC 2129 OpC 06 01 06 +23 19.7   7.31 6.7     ~ 99 0
7 V* NV Mon TT* 06 40 37.8658668075 +09 34 54.107992383 18.689 17.913 16.492 15.63 14.293 M3e 40 0
8 V* V338 Mon TT* 06 40 38.1957770226 +09 29 52.501626276 19.44 18.86 17.37 16.38 15.20 M1e 30 0
9 NGC 2264 84 TT* 06 40 42.1819909416 +09 33 37.422800532 12.575 12.57 12.01 11.74 11.33 G0 64 0
10 ESO-HA 399 TT* 06 40 44.5900833964 +09 32 26.172980605   19.65 18.29 17.23 15.61 M3e 27 0
11 EM* LkHA 364 TT* 06 40 45.1638027115 +09 28 44.402107746 15.82 15.25 14.2 13.59 13.03 K2 39 0
12 V* NY Mon TT* 06 40 47.1122808800 +09 32 40.056838088 17.49 17.57 16.33 15.36 14.28 M1V 41 0
13 V* LT Mon TT* 06 40 49.8919916220 +09 36 49.459472044 16.4 16.49 15.42 14.6 13.80 K4 54 0
14 NGC 2264 108 TT* 06 40 51.1854909871 +09 44 46.107334185 12.684 12.42 12.004 11.661 11.35 F8V 65 0
15 EM* LkHA 33 TT* 06 40 51.5429242864 +09 43 24.229826742 16.31 15.69 14.51 13.85 13.22 K4 51 0
16 V* NZ Mon TT* 06 40 51.5891984425 +09 28 44.516719956 17.85 17.32 16.07 15.21 14.37 K4e 43 0
17 NGC 2264 OpC 06 40 52 +09 52.6           ~ 1649 0
18 KHA 98 TT* 06 40 52.9234295290 +09 44 54.385087744 16.892 16.515 15.339 14.893 13.705 K5/6e 36 0
19 EM* LkHA 35 TT* 06 40 53.6365617652 +09 33 24.733966714 16.095 15.43 14.42 14.07 13.386 K1e 63 0
20 V* GQ Mon TT* 06 40 56.1649954397 +09 36 30.905099792   17.083 17.245 15.19 14.06 K3e 40 0
21 V* LU Mon TT* 06 40 56.8002062552 +09 37 49.031800937 16.22 16.21 15.07 14.23 13.39 K5e 64 0
22 V* V603 Mon TT* 06 40 57.8377400303 +09 41 20.185147944 18.21 17.73 16.27 15.27 14.23 M0 36 0
23 * 15 Mon Be* 06 40 58.65963 +09 53 44.7229 3.360 4.400 4.640   4.88 O7V+B1.5/2V 764 0
24 EM* LkHA 42 TT* 06 40 58.6730868174 +09 36 13.170405288   18.43 17.4 15.97 14.29 M4e 31 0
25 KHA 103 TT* 06 40 58.8259596010 +09 39 18.750384216   17.83 17.02 16.01 14.95 M0e 34 0
26 V* IO Mon TT* 06 40 58.836576 +09 30 57.26412   15.30 14.04 13.11 12.49 K2/3e 60 0
27 ESO-HA 447 TT* 06 40 58.9178440368 +09 28 52.910158617   18.325 16.84   14.43 M1e 21 0
28 V* V421 Mon TT* 06 40 59.5445496967 +09 35 10.865366091 18.05 17.18 15.49 14.44 13.31 K4 49 0
29 V* LV Mon TT* 06 40 59.6792483845 +09 28 43.768662991 17.06 17.05 15.9 15.13 14.14 M1 35 0
30 V* V354 Mon TT* 06 41 00.5099718638 +09 29 15.957184805 16.81 15.94 14.73 14.04 13.34 K4e 48 0
31 V* IP Mon TT* 06 41 00.9823376160 +09 32 44.469147785 15.55 14.77 13.48 12.68 11.92 K1 72 0
32 V* LW Mon TT* 06 41 03.3731245919 +09 40 44.975976849 18.07 17.14 15.81 14.97 14.07 M1 40 0
33 ESO-HA 473 TT* 06 41 03.6067392858 +09 30 29.025828250   19.53 17.79 16.55 14.72 M5 33 0
34 V* V607 Mon TT* 06 41 04.0667889271 +09 35 21.061393760 18.99 18.23 16.72 15.67 14.44 M2.5e 38 0
35 V* LY Mon TT* 06 41 04.2795887837 +09 24 52.182724054 16.44 16.9 15.87 15.03 14.10 M0e 47 0
36 Cl* NGC 2264 FMS 345 TT* 06 41 04.5077396750 +09 30 13.447547395   19.45 18.05 16.87 15.42 Me 19 0
37 NGC 2264 162 TT* 06 41 05.7406766259 +09 31 01.203664346 17.59 16.94 15.44 14.58 13.55 K5e 41 0
38 EM* LkHA 53 TT* 06 41 06.1984756363 +09 36 22.925329198 14.71 14.31 13.43 12.9 12.43 G3V 82 1
39 V* V608 Mon TT* 06 41 06.7366557661 +09 34 45.931259858 18.07 17.51 16.24 15.29 14.28 G6: 43 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 11.8540222133 +09 26 31.451902297 16.66 16.55 15.15 14.28 13.44 K7e 37 0
42 V* V583 Mon TT* 06 41 13.2975688536 +09 31 50.276653812 19.51 19.3 17.71 16.39 14.61 M4e 35 0
43 Cl* NGC 2264 SBL 2420 TT* 06 41 13.3087943395 +09 51 54.452622187 19.38 18.93 17.35 16.36 15.27 M1e 26 0
44 ESO-HA 516 TT* 06 41 14.75400 +09 34 13.4724   19.24 17.87 16.88 15.61 K8/M0e 26 0
45 EM* LkHA 64 TT* 06 41 15.1142037268 +09 26 44.390098918 18.12 17.93 16.66 15.6 14.48 M0.5e 35 0
46 V* OT Mon TT* 06 41 16.6883326658 +09 29 52.258355456 17.64 17.06 15.7 14.81 13.73 K1 35 0
47 V* MN Mon TT* 06 41 16.7841573895 +09 27 30.211208968 16.38 16.36 15.34 14.59 13.91 K4 46 0
48 V* V821 Mon TT* 06 41 17.9246841190 +09 29 01.157217954   20.23 18.28 16.86 15.29 M2.5 32 0
49 EM* LkHA 68 TT* 06 41 18.2762254109 +09 33 53.577554167 16.3 16.05 14.92 14.18 13.51 K4 55 0
50 EM* LkHA 67 SB* 06 41 18.3728099573 +09 39 41.204390169 17.47 17.53 16.36 15.53 14.57 M1e 42 0
51 V* OV Mon TT* 06 41 21.0098817834 +09 33 36.095306948 16.93 16.43 15.16 14.38 13.56 K6e 52 0
52 ESO-HA 528 SB* 06 41 25.6230161455 +09 34 43.009212323 18.14 17.49 16.03 15.31 14.37 M0 40 0
53 ESO-HA 531 TT* 06 41 26.9967046220 +09 30 13.146568541   19.01 17.5 16.45 15.19 M1e 29 0
54 NGC 2264 213 TT* 06 41 28.7798417475 +09 38 38.946278630 15.61 15.03 14.03 13.46 12.89 K3 40 0
55 NGC 2264 499 TT* 06 41 34.5567549569 +09 36 32.466928355 19.56 18.82 17.33 16.31 15.13 M1 30 0
56 V* TW Hya TT* 11 01 51.9054298616 -34 42 17.031550898   11.94 10.50 10.626 9.18 K6Ve 1672 1
57 HD 319139 LM* 18 14 10.4818974563 -32 47 34.516106830   11.47 10.68   9.11 K5+K7 314 0

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2021.11.29-15:55:00

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