2008A&A...490..601S


Query : 2008A&A...490..601S

2008A&A...490..601S - Astronomy and Astrophysics, volume 490, 601-612 (2008/11-1)

Optical spectroscopy of X-ray sources in the Taurus Molecular Cloud: discovery of ten new pre-main sequence stars.

SCELSI L., SACCO G., AFFER L., ARGIROFFI C., PILLITTERI I., MAGGIO A. and MICELA G.

Abstract (from CDS):

We have analyzed optical spectra of 25 X-ray sources identified as potential new members of the Taurus molecular cloud (TMC), in order to confirm their membership in this star-forming region. Fifty-seven candidate members were previously selected among the X-ray sources in the XEST survey, having a 2MASS counterpart compatible with a pre-main sequence star based on color-magnitude and color-color diagrams. We obtained high-resolution optical spectra for 7 of these candidates with the SARG spectrograph at the TNG telescope, which were used to search for lithium absorption and to measure the Hα line and the radial and rotational velocities. Then, 18 low-resolution optical spectra obtained with the instrument DOLORES for other candidate members were used for spectral classification, for Hα measurements, and to assess membership together with IR color-color and color-magnitude diagrams and additional information from the X-ray data. We found that 3 sources show lithium absorption, with equivalent widths (EWs) of ∼500mÅ, broad spectral line profiles, indicating rotational velocities of ∼20-40km/s, radial velocities consistent with those for known members, and Hα emission. Two of them are classified as new weak-lined T Tauri stars, while the EW (~-9Å) of the Hα line and its broad asymmetric profile clearly indicate that the third star (XEST-26-062) is a classical T Tauri star. Fourteen sources observed with DOLORES are M-type stars. Fifteen sources show Hα emission. Six of them have spectra that indicate surface gravity lower than in main sequence stars, and their de-reddened positions in IR color-magnitude diagrams are consistent with their derived spectral type and with pre-main sequence models at the distance of the TMC. The K-type star XEST-11-078 is confirmed as a new member on the basis of the strength of the Hα emission line. Overall, we confirm membership to the TMC for 10 out of 25 X-ray sources observed in the optical. Three sources remain uncertain.

Abstract Copyright:

Journal keyword(s): techniques: spectroscopic - stars: luminosity function, mass function - stars: pre-main sequence - Galaxy: open clusters ans associations: individual: Taurus molecular cloud

Simbad objects: 33

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Number of rows : 33
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           ~ 1314 1
2 HD 281294 ** 03 53 37.3060 +32 04 58.300   11.96 10.87     G5 5 0
3 2MASS J03541064+3148573 Y*? 03 54 10.6381128672 +31 48 57.333538908           ~ 4 0
4 USNO-B1.0 1161-00050238 * 04 04 24.4929451968 +26 11 11.969180736 18.02 17.4   14.7   M2.5V 5 0
5 [GBA2007] 198 X 04 04 27.6599355672 +26 08 34.916748900           ~ 4 0
6 UCAC4 591-011866 TT* 04 14 52.310472 +28 05 59.69616 19.87         M3.1 26 0
7 USNO-B1.0 1172-00072216 TT* 04 20 39.1896395400 +27 17 31.778958336           M4.5V 28 0
8 2MASS J04214372+2647225 PM* 04 21 43.7304234000 +26 47 22.265270304     11.959     ~ 5 0
9 2MASS J04221568+2657060 TT* 04 22 15.6885305568 +26 57 06.241900536 20.98 20.2   17.1   M0.7 27 0
10 2MASS J04222404+2646258 Y*O 04 22 24.0456897408 +26 46 25.959753048           ~ 23 0
11 TYC 1828-409-1 * 04 22 25.5937883664 +28 12 33.420694356   12.81 11.55     ~ 4 0
12 LP 358-731 TT* 04 29 36.2381337192 +26 34 23.484646236 18.70 17.6 16.09 15.0   M4.25V 19 0
13 NAME Tau-Aur Complex SFR 04 30 +25.0           ~ 1297 0
14 LP 358-352 PM* 04 30 17.0360433720 +26 22 26.261846184     16.50     M4.5V 15 0
15 USNO-B1.0 1159-00057240 X 04 31 46.35 +25 58 40.5           ~ 4 0
16 2MASS J04322689+1818230 * 04 32 26.8930144728 +18 18 23.011499052           M2.25V 5 0
17 2MASS J04335252+2256269 TT* 04 33 52.5444689856 +22 56 26.565281232 19.12         M5.5 26 0
18 UCAC4 573-011636 * 04 33 55.6247123520 +24 25 01.613118252 17.30 15.734 14.054 13.628   ~ 6 0
19 2MASS J04343322+2602403 * 04 34 33.2190568752 +26 02 40.167657960   16.1       ~ 5 0
20 USNO-B1.0 1140-00053617 * 04 34 51.6365332344 +24 04 42.601359108           M3.5V 4 0
21 2MASS J04345693+2258358 Y*O 04 34 56.9315751792 +22 58 35.724910224           ~ 23 0
22 V* EZ Tau Er* 04 35 13.1772657408 +22 59 20.380452792   18.3   15.63   M4.75V 30 0
23 2MASS J04354203+2252226 Y*O 04 35 42.0358915080 +22 52 22.614286728           ~ 29 0
24 CoKu HP Tau G1 Y*O 04 35 52.0952581464 +22 55 03.992157300           ~ 26 1
25 2MASS J04355286+2250585 Y*O 04 35 52.8679949808 +22 50 58.515518328 20.06         ~ 25 0
26 ATO J068.9955+22.6430 TT* 04 35 58.9310954280 +22 38 35.265161220 15.37         K7.0 28 0
27 2MASS J04400363+2553547 TT* 04 40 03.6315663000 +25 53 54.739909068           ~ 6 0
28 NAME Taurus Complex SFR 04 41.0 +25 52           ~ 3973 0
29 LDN 1517 DNe 04 55 45 +30 33.0           ~ 108 0
30 2MASS J04555605+3036209 TT* 04 55 56.0536047168 +30 36 20.760468588   16.6       M4.0 29 0
31 XEST 26-135 X 04 56 29.3566681824 +30 36 11.544761088           ~ 4 0
32 M 42 HII 05 35 17.3 -05 23 28           ~ 3919 0
33 NAME Ori A MoC 05 38 -07.1           ~ 2861 0

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2022.08.10-18:26:42

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