The possible connection of PDS Herbig Ae/Be stars
and the Main Star Forming Regions
Wagner J.B. Corradi (UFMG)
Marcelo Guimarães (UFMG)
Sérgio Vieira (UFMG) and Carlos Alberto Torres (LNA)
Departamento de Física - ICEx - UFMG
Abstract
The Pico dos Dias Survey (PDS), a search for new T Tauri stars
conducted at Laboratório Nacional de Astrofísica (LNA - Brazil),
also found 112 new Herbig Ae/Be (HAeBe) candidates. Of these,
19 were later discovered not be HAeBe objects. To improve the
proposed classification of the remaining 93 HAeBe candidates we
looked for other evidences of their pre-main sequence status, investigating the possible relationship between them and the main star
forming regions.
and
Laboratório Nacional de Astrofísica - LNA
Galactic Plane Distribution
To improve the proposed classification of the 93 HAeBe candidates found in the PDS, we looked for other evidences of their pre-main
sequence status, investigating the possible relationship between them and the main SFR. Figure 1 shows a plot of the Galactic distribution
of the HAeBe candidates. As one can see the stars are concentrated around the Galactic Plane, mostly between −25◦ ≤ b ≤ 25◦.
The idea is to combine the distance estimation of the Herbigs stars
with the knowledge of the distribution of the interstellar medium.
The distances to the HAeBe objects were calculated assuming that
the stars are in the main sequence, with Hipparcos distances being
used when available.
Having in mind such limitation, we have found that 74 candidates
seem to be associated with one of the more conspicuous star forming regions, being in the right direction and at a compatible distance.
To 14 stars the proposed association is not clear enough within the
given uncertainties. The remaining five candidates do not have photometry data and no other indicator of their distance could be found.
Data selection
To further investigate the connection between stars and star forming regions, we plotted in Figure 2 (left) the HAeBe stars over the opacity
levels of the photographic Dark Clouds Catalogue (DCC) compiled by Feitzinger & Stuwe (1984). This Figure covers the region delimited
by the Galactic coordinates 15◦ ≤ l ≤ 235◦ and −25◦ ≤ b ≤ 25◦, with the horizontal dashed line representing the Galactic Plane.
Around l ≈ 270◦ there is a well-known tunnel of low reddening near the Galactic Plane, which allow us to find HAeBe candidates even
at great distances. Figure 2 (right) shows the HAeBe stars in the Orion region superposed to the contours of the larger molecular clouds
found by the Columbia millimeter-wave telescope in the third galactic quadrant (Maddalena et al., 1986).
Using the IRAS Point Source Catalog, a search for new T Tauri stars
based on appropriate far-infrared colors was conducted at Laboratório Nacional de Astrofísica (LNA - Brazil), the so called Pico
dos Dias Survey (PDS) (Gregorio-Hetem et al., 1992; Torres et al.,
1995). Since the initial search was based on dust properties and
not on the star itself, the selection criteria included Herbig Ae/Be
(HAEBE) stars.
Using these criteria, the PDS identified 108 HAeBe candidate
stars. Were also included in the sample 4 stars from the IRAS Faint
Source Catalog – HD 290500, GSC8143-1225, GSC8581-2002 and
HD 114981. Of these, 19 stars were later discovered not to be
HAEBE objects, leaving us with 93 objects. For the sake of completness we added to our analysis other 19 stars, that had been
previously identified as young stellar objects, being 10 from Thé et
al. (1994) (TPW) and 9 from Herbig & Bell (1995).
It is important to notice that our sample is less biased towards
bright objects than other catalogs (e.g.TPW; Finkenzeller & Mundt ,
1984; Herbig & Bell, 1995), since the IRAS colors used as selection
criteria are not limited by the source brightness. Our sample also
presents much more southern objects (40% with declination below
-30◦) than the previous catalogs, which is interesting, since it complements the currently available catalogs, such as TPW, that has
only 20% of objects with declination below -30◦.
Proposed Associations
Combining the distance estimation of the Herbigs candidates with the knowledge of the interstellar medium distribution, we have found that
74 candidates seem to be associated with one of the more conspicuous SFR, being in the right direction and at a compatible distance. To
14 stars the proposed association is not clear enough within the given uncertainties. The remaining 5 candidates do not have photometry
data and no other indicator of their distance could be found. In this case only a positional coincidence with the SFR could be given.
The results are summarized in Table 1. The first column contains the star identification in the PDS catalog, except where noticed otherwise.
The following columns contain the Galactic coordinates l and b in degrees, the photometric and Hipparcos distances of the star in parsec,
the distance and name of the proposed star forming region associated to the HAeBe candidate, as well as its reference in the literature.
The last column contains general comments, such as other HAeBe designation or suggestion of associated star forming region. The other
19 stars used to complement the data are also listed at the end of the table.
NAME
Photometry
Johnson UBV(RI)c measurements were gathered in 63 nights during a period of 8 years (from 1990 to 1998). The observations were
collected at LNA with the 60 cm Zeiss Telescope equipped with the
FOTRAP photometer (Jablonsky et al., 1994). Standard stars were
taken from Graham (1982), and the data were reduced using a package developed by Jablonsky et al. (1994). Further details of the
reduction scheme can be found in Torres (1999).
The effective temperatures and distances were determined using
the (B − V ) and (V − I) colors, that are less affected by the presence of emission lines, and the calibrations of Schmidt-Kaler (1982)
and Kenyon & Hartmann (1995). The uncertainty in the determination of the effective temperature is one spectral sub-type for the B
stars and two for the A and F ones (Torres , 1999). The distances
were calculated assuming that the stars are in the main sequence.
Since our main goal is to have indicative values, we used R = 3.2
(Schmidt-Kaler, 1982) for all stars, independently of their position
in the sky. Taking into account the mean errors in the photometry
and effective temperature, the error in the distance varies from 15%
to 22% for stars up to 600 pc from the Sun and 30% for the more
distant ones. When available, Hipparcos distances were used.
The idea is to combine the distance estimation of the Herbigs
candidates with the knowledge of the interstellar medium distribution. Regarding the interstellar medium the information was gathered mainly from previous studies of accurate E(b-y) colour excess
and distance determination to stars covering the medium surrounding the HAEBE candidate (Knude, 1984; Franco , 1990; Corradi et
al., 1997). In some cases, we were able to find kinematic distances
(dkin) to the SFR.
Acknowledgments and Financial Support
S.L.A. Vieira, W.J.B. Corradi and L.T.S. Mendes acknowledge CNPq (grant
number 471537/2001-02), PRPq/UFMG/FUNDEP (grant number 4801) and
FAPEMIG for partial financial support for doing this work. S.H.P.A. acknowledges
support from FAPESP (grant number 00/06244-9) and CAPES (PRODOC program). M.M.G. acknowledges support from CAPES. This research has made
intensive use of the SIMBAD facilities available at CNRS(France).
l
b
168
172
178N
178S
183
4
174.87 -17.06
173.47
-7.90
180.76
-6.19
180.76
-6.19
181.26
-4.77
161.19 -20.46
020E
211
192.14
182.28
-3.60
4.92
176
179
180
114
184
185S
190S
191
192
193
194
198
016
201A
018
25
211.03
200.32
201.07
202.58
193.21
188.50
205.71
210.56
205.50
210.72
209.40
211.25
209.59
204.98
215.88
235.81
-25.61
-18.11
-18.34
-18.46
-12.28
-8.88
-17.25
-19.41
-16.84
-19.38
-18.73
-19.39
-17.43
-14.81
-17.48
-10.50
229N
24
27
249
133
134
257
216.23
227.69
231.81
239.94
239.58
237.00
236.38
-0.49
-8.15
-1.96
-5.03
-4.63
-1.32
1.49
22
124
126
21
130
221.20
213.19
214.40
216.46
219.59
-17.16
-12.56
-11.31
-15.42
-3.79
33
34
290
297
031S
281
272
277
261.62
265.70
274.70
278.86
257.63
265.23
260.26
257.33
1.84
-1.20
-1.46
-2.47
0.25
0.52
-5.60
-1.05
303
37
322N
339
282.88
282.31
286.87
291.58
-3.14
-0.77
2.90
6.81
353
361S
364S
140
57
299.68
304.33
306.25
298.70
294.13
-0.60
0.62
0.29
2.87
1.47
340
61
296.37
300.23
-8.32
-15.59
dHip
dSF R
SFR
TAURUS-AURIGA
130 ± 34
130 - 150
LDN1536
156
150 ± 37 131115
140 - 160
Tau
220 ± 53 150236
140
160
LDN1554
110
220 ± 33 150236
140 - 160
LDN1554
110
140 ± 24 204268
140
160
Tau
165
580 ± 139
250 - 300
Per OB2
GEMINI
1200 ± 216
1200
Gem OB1
1100 ± 231
1200
Gem OB1
ORION
540 ± 130 164224
300 - 460
Ori
129
−
470 ± 113 952330
460 - 650
Ori OB1
300 ± 54 645−
300
460
Ori
280
730 ± 153
460 - 650
Ori OB1
510 ± 168
400
λ Ori
180 ± 32 342742
400
λ Ori
223
550 ± 116
300 - 700
Ori A
320 ± 106
300 - 700
Ori A
270 ± 65
360 - 640
Ori B
600 ± 102
300 - 700
Ori A
230 ± 48
300 - 700
Ori A
190 ± 46
300 - 700
Ori A
480 ± 101 422935
460
650
Ori
OB1
272
521
170 ± 26 285196
460 - 650
Ori B
380 ± 57
300 - 700
Ori A
790 ± 174
670 - 1130 Southern Ori
CANIS MAJORIS
1600 ± 384
1200 - 1300 CMa OB1
1800 ± 432
2000
CMa
1100 ± 407
1200 - 1300 CMa
2300 ± 552
2460
LDN1664
2500 ± 350
2460
LDN1664
1800 ± 252
2090
SS127
3000 ± 840
4300
G236.4+1.49
MONOCEROS
690 ± 166
780 - 880
NGC2149
1000 ± 240
780 - 880
L1646
500 ± 75
780 - 880
Mon R2
1100 ± 121
1200
L1653-1656
1200 ± 420
1200
L1653-1656
VELA AND THE GUM NEBULA
1400 ± 462
1800 - 2190 Vela OB1
2900 ± 1073
1800 - 2190 Vela OB1
1800 ± 270
1800 - 2190 Vela OB1
770 ± 100
700 - 800
DC278.2-2.1
670 ± 160 288490
200
240
Gum Nebula
204
340 ± 31
450
Vela
600 ± 144
500 - 900
Vela
210 ± 23
200 - 240
Gum Nebula
CARINA
500 ± 120
800
DC282.8-3.2
720 ± 266
800
DC282.4+0.5
3800 ± 1064
2500
Car OB1
110 ± 23 111121
120-150
Carina
102
SOUTHERN COALSACK
1200 ± 132
900 - 1400 Coalsack
2700 ± 756
2400
Cen OB1
2600 ± 962
2400
Cen OB1
290 ± 78
150 - 200
Coalsack
410 ± 98
500 - 700
DC295.0+1.3
CHAMAELEON - MUSCA
190 ± 51 103110
100-120
DC296.2-7.9
97
115 ± 28 116124
140
200
Cha
109
dphot
Ref.
1
2
3
3
2
4
Comments
HD31648
V1185 Tau
5
6
7
8
7
8
9
9
7
7
7
7
7
7
8
7
7
10
V1366 Ori
LDN1614
V1409 Ori
HR1847
vdB46
V1247 Ori, vdB50
V599 Ori
V351 Ori
G239.2-16.3
11,8
11
11,8
1
1
12
12
S287(d=2.3kpc)
11
13
14
10
10
AE Lep
V791 Mon
8
8
8
15,16
17
18
16
dkin=2000pc
17
17
17
8
19
SA192
SA192
DC287.7+2.9
SA193
20
8
8
21
21
SS73
close to S131
22
23
HD100546
DX Cha
NAME
l
b
dphot
dHip
NORMA
dSF R
SFR
Ref.
Comments
520 ± 57
600 - 700
Norma
24
600 ± 222
600 - 700
Norma
24
240 ± 53
150 - 200
G317-4
17
Circinus
670 ± 161
500
Circinus
25
Sandqvist 165
1300 ± 312
1400
Norma
24
LUPUS AND OPHIUCHUS
395
333.24 10.19
160 ± 27
130 - 160
Lupus
17
406
338.59
9.35
1200 ± 204
1400
Lupus
24
398A
4.19 36.91
170 ± 41
99108
110
160
ρ
Oph
17,26
91
76
349.91 23.50
120 ± 29
110 - 160
Sco R1
27
78
347.41 17.81
120 ± 20
253405
110
160
ρ
Oph
17,26
183
154
80
352.43 20.44
140 ± 32
131114
110 - 160
ρ Oph/Sco OB2 17,8
415N
352.07 18.44
280 ± 67
110 - 160
ρ Oph/Sco OB2 17,8
LDN1687
139
473
7.24
1.48
160 ± 38
121109
110 - 160
ρ Oph
17,26 HD163296
95
353.11
-0.72
950 ± 86
1000
RCW131
28
96
349.87
-3.54
1300 ± 143
850 - 1150 DC349.8-3.5
29,30 vdB 91
SERPENS AND AQUILA
520
31.14
5.06
180 ± 27
200 - 350
Serpens
31
530E
39.09
5.87
1000 ± 240
1000
W50
32
313
564
49.21
2.88
150 ± 50
244200
200 - 300
Aquila
33
545
40.62
4.09
560 ± 207
600
LDN637
1
STARS FROM PDS WITHOUT CLEAR ASSOCIATION TO STAR FORMING REGIONS
207
181.48
4.60
600 ± 222
LDN1557
34
216
196.93
0.64 2700 ± 1000
850 - 1150 Mon OB1
7
dkin=4700pc
174
203.54 -24.69
1700 ± 476
460
G203.4-24.7
33
L1615/1616
187
208.19 -19.90
1600 ± 336
300 - 700
Ori A
7
UY Ori
225
208.45
2.40
360 ± 115
1600
Rosette
35
dkin=930pc
19
219.84 -18.12
1700 ± 187
850 - 1150 Southern Ori
27
2
293.76 -64.10
340 ± 51
isolated?
344
295.41
-2.70
4100 ± 697
2500
DC296.1-2.5
8
Cru OB1
69
316.49 21.14
1200± 492
100
G316.4+21.2
33
MBM 112
144N
345.61 21.77
2000 ± 480
Magnani124
36
144S
345.61 21.77
1400 ± 238
Magnani124
36
453
359.45
6.15
490 ± 132
LDN1767/1773 34
514
3.40
-7.82
210 ± 50
isolated
469
13.26
6.46
1100 ± 264
LDN330
37
STARS WITHOUT DISTANCE BUT WITH REMARKABLE POSITIONAL COINCIDENCE
HD290500
203.65 -18.27
360 - 640
Ori B
7
GSC8143-1225 264.54 -10.72
DC264.5-11.3
15
Gum Nebula
GSC8551-2002 276.24 -10.60
DC276.10-10.6 15
141
303.04 -14.24
140 - 200
DC303-14
38
DK Cha
HD114981
307.89 24.00
G308.9+24.3
39
STARS FROM OTHER HAEBE CATALOGUES USED TO COMPLEMENT THE DATA
HBC078
172.50
-8.00
144167
140 - 160
Tau-Aur
2
AB Aur
126
370
HD53367
223.70
-1.91
250185
500
vdB 86
29
V750 Mon
HD52721
224.15
-2.87
910−
670
1130
Southern
Ori
10
357
HBC548
224.37
-2.73
670 - 1130 Southern Ori
10
HT CMa
HBC551
224.53
-2.43
670 - 1130 Southern Ori
10
HU CMa
−
HBC552
256.14 -14.07
500228
450
Gum Nebula
18
NX Pup
HD76534N
264.41
1.05
410884
500
Vela
40
OU
Vel
268
884
HD76534S
264.41
1.05
410268
500
Vela
40
OU Vel
HD85567
282.67
-5.43
10003225
800
2500
Carina
41
591
HD98922
289.77
7.23
10402900
1000 - 2000 Centaurus
42
632
HD95881
294.40 -10.47
DC295.3-13
43
Globule 121
Hen847
304.60 13.95
V1028 Cen
HBC596
317.08
-4.19
150 - 200
G317-4
17
Circinus
HBC619
339.53
9.38
210253
130 - 160
Lupus
44
V856 Sco
176
HD150193
355.60 14.85
150200
100
140
Ophiuchus
26
119
HBC288
359.94 -17.84
818
130 - 170
DC359.9-17.9
45
R CrA
5
HBC287
359.99 -17.78
130 ± 20
130 - 170
DC359.9-17.9
45
TY CrA
HBC282
30.46
5.11
200
Aql Rift
7
VV Ser
−
HD190073
46.47 -13.09
5000750
V1295 Aql
399E
399N
389
394W
431
326.98
326.98
318.78
320.94
342.37
-1.24
-1.24
-3.91
-4.99
0.10
To be certain of the association of HAeBe candidates and SFR we need to improve the distance determination of the stars, specially of the
more distant ones, as well as the distance of the less well studied SFRs. Having in mind such limitation, there should be caution on the
use of the proposed associations.
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