1998AJ....116.2530G

Query : 1998AJ....116.2530G

1998AJ....116.2530G - Astron. J., 116, 2530-2535 (1998/November-0)

The incidence of λ Bootis stars via an extension of the MK spectral classification system to very young A-type stars.

GRAY R.O. and CORBALLY C.J.

Abstract (from CDS):

In this paper we introduce an extension to the MK system of spectral classification that allows the precise classification of pre-main-sequence (PMS) A-type stars, including most Herbig Ae stars. This classification scheme characterizes the star by a standard MK type, the presence and strength of emission and/or shell lines, and the strength of the Balmer decrement. It can be used to summarize temporal spectral changes in PMS A-type stars, and to search for peculiar types. We have used this scheme to classify 38 Herbig Ae stars as well as 22 PMS stars in the young open clusters NGC 2264, NGC 7160, and IC 348. We have also used this extended system to search for λ Boötis stars among PMS A-type stars. We have found one definite λ Boötis star among the Ae stars, and one marginal λ Boötis star in NGC 2264, yielding statistics not significantly different from those of the λ Boötis stars in the field. This, in addition to other considerations from previous studies, leads us to conclude that the λ Boötis mechanism is operable from very early ages (PMS) to well into the main-sequence life (a few times 108 yr) of only 2%-3% of A-type stars.

Abstract Copyright: ∼

Journal keyword(s): Stars: Circumstellar Matter - Stars: Chemically Peculiar - Stars: Emission-Line, Be - Stars: Individual: Henry Draper Number: HD 37411 - Stars: Individual: Constellation Name: IP Persei - Stars: Pre-Main-Sequence

Simbad objects: 65

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Number of rows : 65
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 V* VX Cas Ae* 00 31 30.6818495040 +61 58 50.984946300 11.83 11.59 10.50 11.19 10.94 A0Vep 132 0
2 HD 278937 Y*O 03 40 46.9605708144 +32 31 53.715087444   10.66 10.40     A7III:kA2.5mA3e(r) 85 0
3 HD 281160 * 03 44 08.4690100008 +32 07 16.556383164   10.40 9.94     A0 39 0
4 IC 348 OpC 03 44 31.7 +32 09 32           ~ 1393 1
5 IC 348 12 Y*O 03 44 35.3610354384 +32 10 04.591121088       10.06 9.098 A2 65 0
6 V* XY Per Ae* 03 49 36.3365862552 +38 58 55.548299928 12.12 10.14 9.58 9.54 8.40 A2II+B6 151 0
7 V* AB Aur Ae* 04 55 45.8458932216 +30 33 04.292077032 7.20 7.16 7.05 6.96 6.70 A0Ve 1067 2
8 HD 31648 Ae* 04 58 46.2655706952 +29 50 36.987625680 7.84 7.78 7.62 7.76 7.43 A5Vep 518 0
9 V* UX Ori Ae* 05 04 29.9878898040 -03 47 14.286732072 10.25 10.93 8.70 9.62 9.43 A4IVe 363 1
10 HD 32509 Y*O 05 04 50.1335426736 +26 43 14.786719752   7.69 7.52     A2e 30 0
11 V* V1366 Ori Ae* 05 16 00.4765181328 -09 48 35.393784012 10.19 10.16 9.84 9.77 9.63 B9.5V 209 0
12 HD 34250 Em* 05 17 15.4619226864 +28 54 18.045842724 7.920 7.450 6.780     F0 38 0
13 HD 35187 Y*O 05 24 01.17261 +24 57 37.5791   8.79 8.71 8.72   A2e+A7 107 0
14 HD 287841 Y*O 05 24 42.8032369656 +01 43 48.249234516 10.55 10.45 10.17 9.99 9.80 A8V 110 0
15 HD 35929 dS* 05 27 42.7906489200 -08 19 38.446702140   8.55 8.11     F2IV/V 111 0
16 HD 244314 Or* 05 30 19.0247390376 +11 20 20.002720452   10.33 10.18     A1V 28 0
17 HD 36112 Ae* 05 30 27.5285630040 +25 19 57.076288752   8.57 8.27     A8Ve 469 0
18 V* HK Ori Ae* 05 31 28.049808 +12 09 10.30212 11.82 12.235 11.716 11.632 10.56 A2?e+G0?e 193 1
19 HD 244604 Or* 05 31 57.2511172320 +11 17 41.368840404   9.61 9.43     A0Vesh 75 0
20 HD 245185 Ae* 05 35 09.6034684104 +10 01 51.465413208 10.05 10.07 9.93     A0Vae 127 0
21 V* T Ori Ae* 05 35 50.4482802768 -05 28 34.925254536 12.724 11.637 11.248 10.09 10.043 A8VnekA1mA2_lB 247 0
22 V* BF Ori Ae* 05 37 13.2623828280 -06 35 00.568242528 10.37 10.00 9.69 10.06 9.31 A7III 293 0
23 HD 37357 Ae* 05 37 47.0794735560 -06 42 30.209473224   8.96 8.85     A3VankA1 109 0
24 HD 37411 Or* 05 38 14.5072831944 -05 25 13.301118588 10.03 9.91 9.79 9.60 9.45 hA3VakA0mA0(eb)_lB 90 0
25 HD 37806 Be* 05 41 02.2930798296 -02 43 00.731764812 7.67 7.93 7.90     B9/9.5II/III 160 0
26 V* V351 Ori Ae* 05 44 18.7949456328 +00 08 40.410217104 9.44 9.22 8.87     A7V 116 0
27 HD 250550 Ae* 06 01 59.9892055464 +16 30 56.727549864   9.60 9.593 9.64   B9e 244 1
28 V* V588 Mon dS* 06 39 05.9036624568 +09 41 03.432957252   9.93 9.75     A5/7 55 0
29 HD 261586 * 06 39 53.5866155304 +09 22 13.947787452   10.63 10.4     ~ 24 0
30 HD 261658 * 06 40 03.9921437952 +09 22 42.963084192   10.52 10.3     A0/1 15 0
31 HD 261736 Y*O 06 40 24.7564257840 +09 46 08.205829968 9.53     9.305 8.787 A5/7 53 0
32 NGC 2264 OpC 06 40 52.1 +09 52 37           ~ 1793 0
33 HD 261904 Y*O 06 41 00.6874797312 +09 24 11.888973612   10.38 9.50     A0/1 38 0
34 BD+09 1340 Y*O 06 41 01.5552520368 +09 28 13.060448436   10.68 10.64 10.67 10.56 A0 29 0
35 HD 261939 TT* 06 41 04.7073214128 +09 36 26.706104244 11.008 11.03 10.96 10.98 10.815 B8 42 0
36 HD 261941 TT* 06 41 05.8757621928 +09 22 55.630818372   11.08 10.94     A2/3 45 0
37 HD 262015 * 06 41 11.2643649576 +09 11 15.636051744   10.43 10.5     A2/3 19 0
38 HD 262108 * 06 41 34.6124873592 +09 51 37.917306504 10.177 10.1 10.0   9.701 A2/3 33 0
39 HD 262138 * 06 41 42.0646601184 +09 47 36.084971868 9.926 9.77 9.52   9.472 A2/3 23 0
40 HD 50138 Ae* 06 51 33.3989823840 -06 57 59.450772852 6.28 6.68 6.67     A1Ib/II 220 0
41 HD 58647 Em* 07 25 56.0985504216 -14 10 43.548632256 6.81 6.92 6.85 6.73 6.73 B9IV 96 0
42 HD 141569 Y*O 15 49 57.7482550392 -03 55 16.341617064 7.22 7.20 7.12 7.00 7.04 A2VekB9mB9(_lB) 540 0
43 HD 150193 Ae* 16 40 17.9243127240 -23 53 45.193372692 9.69 9.32 8.79 8.41   A3Va(e) 321 0
44 * c Oph Be* 17 31 24.9538710166 -23 57 45.514802684 4.75 4.81 4.81 4.74 4.72 A0V 273 0
45 HD 163296 Ae* 17 56 21.2881851168 -21 57 21.871819008 7.00 6.93 6.85 6.86 6.67 A3VaekA1mA1 1111 0
46 V* VV Ser Ae* 18 28 47.8620017808 +00 08 39.923474964 12.99 12.63 11.80 11.01 10.24 A5Ve 249 0
47 V* WW Vul Ae* 19 25 58.7494120560 +21 12 31.333658616 11.46 10.99 10.25 10.38 10.12 A2IVe 224 0
48 HD 190073 Ae* 20 03 02.5098474264 +05 44 16.660712904 7.91 7.86 7.73   7.65 A2IVe 256 0
49 EM* LkHA 324 Ae* 21 03 54.2279744856 +50 15 09.993001896   13.79 12.61 11.89 11.14 B9Ve 66 0
50 IRAS 21023+5002 mul 21 03 57.6 +50 14 38           ~ 55 0
51 HD 203024 SB* 21 16 03.0525752328 +68 54 52.080755040   9.02 8.86     A5V 50 0
52 HD 235495 Em* 21 21 27.4972171680 +50 59 47.633714304   9.872 9.62     A0 21 1
53 BD+46 3471 Ae* 21 52 34.0992801288 +47 13 43.605617340 10.72 10.56 10.15     A0.5IIIer 210 1
54 NGC 7160 8 * 21 52 50.8959801648 +62 30 34.738990452   10.98 10.7     F5V 3 0
55 NGC 7160 11 * 21 53 02.1235574088 +62 30 42.165363816   11.4 11.7     A0 3 0
56 NGC 7160 12 * 21 53 12.8816222184 +62 35 01.012587576   11.96 11.41     F7V 3 0
57 NGC 7160 13 Y*? 21 53 33.3121688808 +62 37 20.327284020   11.77 11.48     B9 7 0
58 NGC 7160 16 Y*? 21 53 40.5639286200 +62 35 26.174551272   11.94 11.68     B9 4 0
59 NGC 7160 OpC 21 53 48 +62 35.3   6.34 6.1     ~ 235 0
60 NGC 7160 14 * 21 53 57.9493715232 +62 37 32.560736268   11.3 11.1     A0 5 0
61 NGC 7160 19 Y*? 21 54 00.4100679144 +62 33 55.965778092   12.63 12.24     A0.5 3 0
62 NGC 7160 9 Y*? 21 54 07.6503109008 +62 32 21.403863744   10.9 10.8     B9V 11 0
63 NGC 7160 15 * 21 54 11.8341935136 +62 32 44.227854816   12.19 11.64     A5 3 0
64 NGC 7160 18 Y*? 21 54 23.4173697600 +62 35 44.964712392   12.48 12.14     B9V 13 0
65 V* SV Cep Ae* 22 21 33.2166238512 +73 40 27.097678812 11.40 11.25 10.35 10.28 10.08 A2IVe 130 0

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