2000A&A...353.1044H

Query : 2000A&A...353.1044H

2000A&A...353.1044H - Astronomy and Astrophysics, volume 353, 1044-1054 (2000/1-3)

ROSAT PSPC observations of T Tauri stars in MBM 12.

HEARTY T., NEUHAEUSER R., STELZER B., FERNANDEZ M., ALCALA J.M., COVINO E. and HAMBARYAN V.

Abstract (from CDS):

We present the ROSAT PSPC pointed and ROSAT All-Sky Survey (RASS) observations and the results of our low and high spectral resolution optical follow-up observations of the T Tauri stars (TTS) and X-ray selected T Tauri star candidates in the region of the high galactic latitude dark cloud MBM 12 (L1453-L1454, L1457, L1458). Previous observations have revealed 3 ``classical'' T Tauri stars and 1 ``weak-line'' T Tauri star along the line of sight to the cloud. Because of the proximity of the cloud to the sun, all of the previously known TTS along this line of sight were detected in the 25ks ROSAT PSPC pointed observation of the cloud. We conducted follow-up optical spectroscopy at the 2.2-meter telescope at Calar Alto to look for signatures of youth in additional X-ray selected T Tauri star candidates. These observations allowed us to confirm the existence of 4 additional TTS associated with the cloud and at least 2 young main sequence stars that are not associated with the cloud and place an upper limit on the age of the TTS in MBM 12∼10Myr. The distance to MBM 12 has been revised from the previous estimate of 65±5pc to 65±35pc based on results of the Hipparcos satellite. At this distance MBM 12 is the nearest known molecular cloud to the sun with recent star formation. We estimate a star-formation efficiency for the cloud of 2-24%. We have also identified a reddened G9 star behind the cloud with Av∼8.4-8.9mag. Therefore, there are at least two lines of sight through the cloud that show larger extinctions (Av>5mag) than previously thought for this cloud. This higher extinction explains why MBM 12 is capable of star-formation while most other high-latitude clouds are not.

Abstract Copyright: ∼

Journal keyword(s): stars: formation - ISM: clouds

VizieR on-line data: <Available at CDS (J/A+A/353/1044): table4.dat table4.ps table4.tex>

Nomenclature: Table 4: [HNS2000] NN (Nos 1-77), [HNS2000] NNa (Nos 49a-49b, 51a-51b).

Simbad objects: 100

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Number of rows : 100
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024 		#notes
1 HD 17332 ** 02 47 27.42146 +19 22 18.5443           G1V+G5V 100 0
2 RX J0247.5+1855 X 02 47 31.0 +18 55 05           ~ 1 0
3 LEDA 138537 Sy1 02 47 40.8457737264 +19 40 57.824917500   16.77 16.66     ~ 48 0
4 RX J0249.0+1653 X 02 49 03.2 +16 53 20           ~ 2 0
5 IC 1854 Sy1 02 49 20.6915840376 +19 18 14.440530996   15.86 14.81     ~ 115 0
6 [VV2006] J025038.0+171208 BLL 02 50 37.9604160096 +17 12 08.881094160   17.7 17.50     ~ 64 1
7 [DB2002b] G157.98-35.06 MoC 02 51 07.7 +19 32 20           ~ 18 0
8 RX J0251.7+1708 X 02 51 44.9 +17 08 21           ~ 1 0
9 RX J0253.8+1943 X 02 53 51.8 +19 43 30           ~ 1 0
10 RX J0254.4+1929 X 02 54 29.4 +19 29 14           ~ 1 0
11 RX J0254.5+1921 X 02 54 34.8 +19 21 10           ~ 1 0
12 RX J0254.6+1955 X 02 54 41.9 +19 55 02           ~ 1 0
13 * rho01 Ari * 02 54 55.2047449800 +17 44 05.080846776 7.310 7.280 7.000     A3 35 0
14 RX J0255.0+2055 X 02 55 02.7 +20 55 08           ~ 1 0
15 HD 18090 * 02 55 05.0979571056 +20 48 00.809005824   9.26 8.82     F2 14 0
16 RX J0255.0+2011 X 02 55 05.1 +20 11 45           ~ 1 0
17 TYC 1227-684-1 * 02 55 16.5979043928 +19 15 01.457413200   10.99 10.54     F8V 8 0
18 RX J0255.4+1953 X 02 55 25.5 +19 53 08           ~ 1 0
19 V* BS Ari TT* 02 55 25.8088286216 +20 04 51.398515764   13.50 12.20     K5.5 21 0
20 RX J0255.6+2007 X 02 55 36.4 +20 07 07           ~ 2 0
21 HD 18190 ** 02 55 49.4782087365 +19 09 12.784673093   9.41 9.04     F 19 0
22 LDN 1457 DNe 02 55.9 +19 35           ~ 85 1
23 RX J0255.9+2005 X 02 55 57.1 +20 05 55           ~ 2 1
24 LDN 1453 DNe 02 56.0 +20 17           ~ 25 0
25 RX J0256.0+1926 X 02 56 01.7 +19 26 58           ~ 1 0
26 V* BU Ari Or* 02 56 07.9958860128 +20 03 24.205352688   15.14 14.15 14.50   M1:IIIe 56 1
27 V* XY Ari CV* 02 56 08.19048 +19 26 34.1844           ~ 157 1
28 V* BV Ari Or* 02 56 08.424288 +20 03 38.57004   16.93 15.42 14.37   M3Ve 38 0
29 LAMOST J025617.98+200610.0 TT* 02 56 17.9839539096 +20 06 09.981012708           dM6 9 0
30 * rho Ari PM* 02 56 26.1717266513 +18 01 23.665188613   6.02 5.58 5.3   F6V 158 0
31 RX J0256.5+1921 X 02 56 34.8 +19 21 53           ~ 1 0
32 V* WY Ari Or* 02 56 37.5658451640 +20 05 37.249715436   13.29 12.46     K5/6e 84 0
33 RX J0256.6+1859 X 02 56 41.2 +18 59 43           ~ 1 0
34 HD 18283 * 02 56 46.0640423520 +21 25 41.156335560   9.12 8.78     A5 27 0
35 LDN 1454 DNe 02 56.8 +20 12           ~ 26 0
36 RX J0256.8+1949 X 02 56 49.0 +19 49 16           ~ 1 0
37 MBM 12 MoC 02 56 50 +19 32.0           ~ 224 1
38 RX J0257.0+1916 X 02 57 01.0 +19 16 24           ~ 1 0
39 RX J0257.1+1859 X 02 57 09.0 +18 59 29           ~ 1 0
40 [HNS2000] 49a ? 02 57 16.8 +20 26 18           ~ 1 0
41 RX J0257.2+2026 X 02 57 16.8 +20 26 18           ~ 1 0
42 [HNS2000] 49b ? 02 57 16.8 +20 26 18           ~ 1 0
43 RX J0257.3+1908 X 02 57 24.0 +19 08 27           ~ 1 0
44 [HNS2000] 51a ? 02 57 25.9 +20 15 35           ~ 1 0
45 [HNS2000] 51b ? 02 57 25.9 +20 15 35           ~ 1 0
46 RX J0257.4+2015 X 02 57 25.9 +20 15 35           ~ 1 0
47 RX J0257.4+1948 X 02 57 28.3 +19 48 19           ~ 1 0
48 2MASS J02573101+1943459 Y*O 02 57 31.0032558144 +19 43 45.915422376           M3 3 0
49 RX J0257.6+1912 X 02 57 39.8 +19 12 19           ~ 1 0
50 LDN 1458 DNe 02 57.8 +20 12           ~ 24 1
51 RX J0257.8+1944 X 02 57 53.5 +19 44 43           ~ 2 0
52 RX J0257.9+1942 X 02 57 55.1 +19 42 54           ~ 1 0
53 * 47 Ari PM* 02 58 05.2213070040 +20 40 07.442238720   6.230   5.6   F0V(e) 187 0
54 BD+18 381 PM* 02 58 09.5791579488 +19 30 00.366022764   11.47 10.53 10.31   K0V 6 0
55 V* BX Ari Or* 02 58 11.231808 +20 30 03.14712   13.01 11.84 11.99   K2.0 37 0
56 V* BY Ari Or* 02 58 16.0931391192 +19 47 19.347297972           M3.8 13 0
57 RX J0258.3+1932 X 02 58 21.3 +02 58 21           ~ 1 0
58 RX J0258.5+1914 X 02 58 31.2 +19 14 47           ~ 1 0
59 RX J0258.6+2020 X 02 58 39.2 +20 20 33           ~ 1 0
60 RX J0258.7+1947 X 02 58 43.0 +19 47 06           ~ 1 0
61 RX J0258.7+1922 X 02 58 45.6 +19 22 44           ~ 1 0
62 RX J0258.8+2025 X 02 58 50.9 +20 25 59           ~ 1 0
63 RX J0259.0+1940 X 02 59 02.0 +19 40 35           ~ 1 0
64 RX J0259.1+1958 X 02 59 08.3 +19 58 32           ~ 1 0
65 HD 18508 PM* 02 59 10.3970263656 +19 59 23.423080128 7.720 7.710 7.350     F0 47 0
66 * eps Ari B * 02 59 12.678278 +21 20 24.26202   5.61 5.57     A3IVs 77 0
67 * eps Ari ** 02 59 12.72536 +21 20 25.5575 4.75 4.67 4.63 4.58 4.56 A2IV+A3IVs 45 0
68 * eps Ari A * 02 59 12.7258032120 +21 20 25.538577396   5.21 5.16     A2IV 73 0
69 RX J0259.2+1930 X 02 59 13.9 +19 30 12           ~ 1 0
70 RX J0259.3+2009 X 02 59 23.7 +20 09 59           ~ 1 0
71 [DB2002b] G161.59-35.89 MoC 02 59.4 +17 12           ~ 13 0
72 RX J0259.4+1942 X 02 59 24.7 +19 42 20           ~ 1 0
73 RX J0259.4+1926 X 02 59 29.9 +19 26 25           ~ 1 0
74 RX J0259.6+1934 X 02 59 40.0 +19 34 07           ~ 1 0
75 RX J0259.7+1952 X 02 59 43.7 +19 52 28           ~ 1 0
76 RX J0259.7+1915 X 02 59 44.1 +19 15 49           ~ 1 0
77 RX J0259.7+1932 X 02 59 45.0 +19 32 48           ~ 3 0
78 RX J0259.8+2013 X 02 59 50.1 +20 13 36           ~ 1 0
79 RX J0259.9+1945 X 02 59 59.1 +19 45 31           ~ 1 0
80 RX J0300.4+2011 X 03 00 24.4 +20 11 22           ~ 1 0
81 * 50 Ari ** 03 00 31.5051140088 +18 00 17.928599148   6.82 6.80     A0 32 0
82 RX J0300.7+1742 X 03 00 45.3 +17 42 08           ~ 2 0
83 RX J0301.7+1834 X 03 01 46.0 +18 34 34           ~ 2 0
84 RX J0302.0+1729 X 03 02 00.2 +17 29 45           ~ 1 0
85 2MASS J03022104+1710342 TT* 03 02 21.0374555016 +17 10 34.377967992     13.5     M2.6 20 0
86 RX J0302.9+1757 X 03 02 57.7 +17 57 16           ~ 2 0
87 RX J0303.5+1742 X 03 03 35.9 +17 42 41           ~ 1 0
88 RX J0304.2+2011 X 03 04 16.5 +20 11 11           ~ 3 0
89 RX J0304.3+2118 X 03 04 21.5 +21 18 02           ~ 3 0
90 RX J0304.6+1940 X 03 04 39.4 +19 40 58           ~ 1 0
91 RX J0304.8+1957 X 03 04 53.9 +19 57 53           ~ 1 0
92 RX J0305.2+1816 X 03 05 17.2 +18 16 38           ~ 2 0
93 RX J0305.8+2055 X 03 05 49.5 +20 55 07           ~ 1 0
94 2MASS J03061174+1829413 AG? 03 06 11.7534987000 +18 29 41.373985596           ~ 2 0
95 RX J0306.5+1921 * 03 06 33.1 +19 21 52     11.4     K1 5 1
96 Cl Melotte 22 OpC 03 46 24.2 +24 06 50           ~ 3435 0
97 LDN 1495E Cl* 04 13 30.7 +28 19 15           ~ 33 0
98 NAME eta Cha Association OpC 08 42 32.9 -78 57 47           ~ 363 0
99 IC 2602 OpC 10 42 27.1 -64 25 34           ~ 675 0
100 NAME TW Hya Association As* 11 01.9 -34 42           ~ 942 0

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