A Study of IR Sources in the Galaxy*) Moedji Raharto**) *)Presented in ITB – GAO Joint Workshop in Astronomy and Science Education 2007, Basic Science Center A, ITB Campus in Bandung, July 4, 2007 **) Research Division Astronomy, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung
ABSTRACT The near Infrared and Infrared astronomical survey reveal distant cool stars in the Galaxy. Most of the cool stars are K or M giants with circumstellar dust, some of M supergiants with circumstellar dust. Those objects, cool giants and supergiants will be among the brightest infrared source in the Galaxy. The interstellar extinction in infrared is very low compared the interstellar extinction in visual band. The IR sources will be good to study galactic structure as well as the stellar evolution.
INTRODUCTION In general ground based and space based astronomical survey in near InfraRed (0.7 – 1 μm) and InfraRed ( 1 – 100 μm) detected many InfraRed (IR) point sources. Most of the IR point sources may not easily identified with optical point sources due to the limiting magnitude of such object beyond the limiting magnitude of optical survey. Raharto (1996) showed the identified bright optical luminous red stars such K and M giants and supergiants (222 out of 228 Miras, 238 out of 243 K and M giants, 86 out of 91 K and M supergiants) with InfraRed Point Source (IPSs) in the IRAS Point Source Catalog. In Magnitude scale mλ = –2.5 log fλ + Cλ, Cλ is constant for mλ = 0; for λ= 12μm, C12 = 28.3 Jy; for λ = 25μm, C25 = 6.73 Jy, for λ = 60μm, C60 = 1.19 Jy dan for λ= 100 μm, C100 = 0.43 Jy. Then infrared color, m12 – m25 = – 2.5 log (f12(Jy)/f25(Jy)) + 1.56, m12 and m25 are magnitude, a logarithmic scale of flux density at 12 μm, f12 ( in Jansky), and 25 μm, f25 (in Jansky). It was found that typical M giants without circumstellar dust had infrared color m12 – m25 = 0, and M Miras and M Supergiants had typical Infrared color m12 – m25 between 0.2 and 1.6. If the cool giants or supergiants stars are perfectly black body radiator without circumstellar dust, the estimated color m12-m25 is around 0. The redder color of the IR sources may come from the stellar radiation in shorter wavelength region converted into IR radiation by circumstellar dust, then more IR radiated from the stars and the circumstellar dust. Raharto (1996) provided the infrared frequency distribution of infrared color m12 – m25 of 68775 ( out of 71567 ). The IPSs showed a bimodal distribution with the first peak at m12 – m25 = 0.1 with half maximum with of 0.1 and the second m12 – m25 = 0.9 with half maximum with of 0.5. The reproduce picture provide by Sugianto and Raharto (2006) as follows.
LUMINOUS IR STARS IN THE BULGE OF THE GALAXY
Raharto (1996) shows the surface distribution of IR luminous stars with color 0.4 < m12 – m25 < 1.4 in the galactic latitude and longitude, the plot shows the bulge structure of the Galaxy. The distance to the galactic Bulge can be estimated, the bulge structure dominated by IRAS Point Source, IPS sources with magnitude range of 2.0 < m12 < 3.0. Estimation of IR efficiency of the IPS shows that the IR bulge stars may be intermediate mass stars. Raharto, Okamura, and Hamabe (2002) using the possible distance to the bulge of the Galaxy and a relation of InfraRed (IR)-color and IR - absolute magnitude of IR stars, then the probable luminosity of IR stars with color range, 0.4 < m12 – m25 < 1.4 are estimated. The range of lower limit of bolometric magnitude of those IPS is estimated around -4.0 and -6.0. Stars which have IPS counterpart, are known as optical – IR stars. Some of late M type stars obtained from Bosscha M Stars Survey in the catalogue of M stars (Raharto, et al., 1984) are optical – IR stars and found as cool IR luminous stars with absolute magnitude in near IR, I band of -10 < MI < -6 (see more example of stars in Table 3-1 and 3-2). Those stars should be located in upper right part of the theoretical HR diagram, which lay out side the most right part of theoretical HR diagram. Using IPS with 0.4 < m12 – m25 < 1.4 and Galaxy Model developed by K. Ishida and S. Okamura in 1993, Raharto (1996) search for global parameter of the Galaxy. It found the best solution that space number density at Galactic Centre n0 = 284 ± 17 (kpc-3), scale height ze = 0.9 ± 0.07 kpc, scale length Re = 4.9 ± 0.3, distance to Galac tic Centre R0 = 7.1± 0.7, average absolute magnitude at 12μm M0= -11.0± 0.1 mag, dispersion of absolute magnitude σ= 1.0 ± 0.1 mag and interstellar absorption in IR A=0.03 ± 0.01 mag/kpc .
OPTICAL – INFRARED STARS Optical - Infrared Stars (1) Bright Stars with good flux quality of 12 µm and 25 µm are selected. It was found 923 or about 10% out of 9110 bright stars. The InfraRed color (IR-color) was defined as m12-m25 = -2.5 log (f12/f25) + 1.56, f12 and f25 were InfraRed flux density of IRAS Point Source at 12 µm and 25 µm in Janskies. The IR-color of the selected Bright Stars was examined. 246 out of 923 are known as double stars. 84% out of 923 are late type spectral class (G,K and M stars). The range of IR-color, (m12 – m25), is between 0.0 and 1.2 [0.0 < (m12-m25) < 1.2], no clear distinction of IR-color between single and binary stars. 13% out of 923 are early type spectral class (F,A and B stars), the range of IR-color between 0.0 and 3.0, no clear distinction of IRcolor between single and binary stars. 3% out of 923 are O, WR, S and C stars IR-Color of Single and Double Stars Normal stars should have IR-color, m12-m25, around 0.0 (photospheres color in longer wavelength). The 10% error of flux densities in IRAS’s photometry implies 0.2 magnitude error in the IR-color. Then the IR-color of bright stars especially larger value has significant intrinsic IR-color. The total photospheres fluxes of unresolved component (angular separation less than 30″ second of arc) would not high up the IR-color significantly. The redder IR-color indicates the existence of circumstellar dust (CSD). The origin of CSD comes from the remnant of parent nebulosity matter (for young object) or mass loss from the stars (for highly evolved stars). Detail study of individual star may help to explain a variety of IRcolor of single and binary stars in the same spectral and luminosity class.
To stabilize CSD around the binary system then [{(a3/P2) x (1/LT)} < {(1/4π G) x (g/σTs4) x (1/M)}], a = separation in AU unit; P = period (in sidereal year unit); LT = total luminosity of the system; G = gravitational constant; σ = Stefan Boltzmann constant; g= gravitational acceleration of the system; Ts = temperature of the system; M= mass of the system. To stabilize CSD around single star should have a condition: [ L0.74 > {4π G c / χ } ], where L = stellar luminosity; G = gravitational constant; c = speed of light; χ = scattering coefficient per unit mass. Table 1: Counterpart of IR sources with good flux quality in IR color, m12 – m25, in Bright star Catalogue. Column 1: MK Spectral type, column 2&3: total number IR sources with Bright Stars counterpart for each spectral type, column 3: the same column 2 in percentage, column 4: known double stars of each spectral type.
• • • • • • • • • • •
•
Sp Type M K G F A B O WR C S Total
total 387 325 66 24 24 66 1 2 19 9 923
(%) 42 35 7 3 3 7
Double Stars 67 90 34 12 11 28 1 2 1 0 246
Table 2: Example of data: Are they candidates of PPNe? Column 1: Bright Stars Number, column 2: Apparent Visual magnitude, column 3: color index (B – V), column 4: magnitude in 12 μm, column 5: infrared color, C = m12 – m25, column 6: color index V – m12 and column 7: Morgan Keenan (MK) spectral type.
• • • • • • • • • • • • • • •
BS No 8752 9045 5880 7296 8232 6030 6536 1605 1865 6685 4912 829 1017 1922
4.99 4.40 .80 6.10 2.89 3.84 2.87 2.99 2.59 5.47 6.76 6.00 1.79 3.40
V 1.29
0.84 1.10 0.54 0.22 0.35
0.48 0.80
B-V 0.84 0.36 -0.35 -1.09 0.61 0.82 0.13 1.21 1.36 -1.34 3.39 3.56 0.03 1.43
m12 0.28 0.22 0.67 0.39 -0.03 -0.08 -0.08 0.26 0.00 0.93 1.83 0.28 0.04 -0.03
C 4.15 4.04 6.15 7.19 2.28 3.02 2.74 1.78 1.23 6.81 3.37 2.44 1.76 1.97
V- m12 MK Sp type G4v O G2 Oe G0 Iep G0 Iep G0 Ib (ds) G2 Ib- (ds) G2 Ib- (ds) F0 Iae (ds) F0 Ib F2 Ibe F3 Ia F5: Ib F5 Ib F6 Ia
In general the infrared color, m12 – m25, of F and G supergiants ( surface effective temperature range between 5500 – 7000 K) without circumstellar dust will be m12– m25=0. Some of bright stars with spectral type of F and G supergiants with infrared
excess indicate the existence of circumstellar dust around the stars. For dwarf mainsequence the infrared color 0.00 < (K–M) <0.03, K (λiso = 2.179 µm) dan M (λiso = 4.769 µm). There are three possible explanation for the IR excess: (1) It is just an observational error, (2) It is double stars or (3) It is a circumstellar dust. The first and the second may not produce a large IR excess, then the possible explanation due to circumstellar dust (Raharto, 1996). The origin of circumstellar dust may comes from parent cloud for young stellar objects or may be ejected from the stars in the stage of post AGB evolution. Tram (1991) found that such stars HR4049 is proto planetary nebula or the star on the way to planetary nebula phase. Optical - Infrared Stars (2) Some known late M type stars which are known as optical IR stars in Bosscha M Stars Survey are found a cool IR luminous stars in the theoretical HR diagram. Red Star (mostly M giants, Miras and Supergiants), based on study of optical – IR stars, it came to the conclusion that IPS with IR color 0.4 < C = m12 – m25 < 1.4, (Raharto, 1996) will be K and M Miras and Supergiants. They probably have absolute magnitude in the range of –12.8 < M12 < −11.2 and bolometric absolute magnitude in the range of –7 < Mbol < −4. Those IR stars can be detected beyond 15 kpc in IRAS Point Source Catalogue. The IPS gave challenge to explore the global structure of the Galaxy and the properties of stellar evolution on the most right side of the HR diagram. Table 3-1. Early-IPS/M stars with 0.7 < C < 1.6 in the BMSS M Star Catalog IRAS NAME 173872958 173892729 174092909 174342940 174682900 172733640 172843229 172913401 173153414 173223159 173433459 173483207 173743156 173933004
Sp.Typ e M3 M2 M1 M3
m1 2 1 .26 2 .70 1 .79 1 .77
M4
-0.59
M4
0.78
M3
1.59
M3
0.62
M3
-1.26
M3
0.17
M4
1.48
M4
-0.62
M3
-1.39
M4
-2.39
C 0 .96 1 .09 0 .96 0 .88 0 .97 1 .01 0 .95 1 .12 1 .08 1 .08 0 .79 1 .22 1 .14 1 .39
M1 2
d (kpc)
-11.85
4.19
-12.25
9.77
-11.85
5.35
-11.60
4.72
-11.88
1.81
-12.00
3.60
-11.82
4.81
-12.34
3.91
-12.22
1.56
-12.22
3.01
-11.32
3.63
-12.65
2.55
-12.40
1.59
-13.17
1.43
Ik 9. 7 < 8.8 1 1.2 8. 9 < 8.8 7. 5 9. 1 < 7.2 < 7.2 1 0.4 < 7.2 8. 9 9. 6 1 0.8
(R I)k
A rk
M Ik
3.3
6 .45
-9.8 6
-
-
0 .88 3 .22
-3.3 2 -7.6 9
-
-
R=9. 7 1.2 2.2 R=9. 2 2.4 2.9
3 .52 5 .27
-8.8 -9.5 8
R=9. 0 R=8. 4 3.4
6 .74
-8.7 3
4 .69 8 .20
-7.8 2 -9.6 1
R=8. 7 2.8 3.9 -
Table 3-2. Late-IPS/M stars with 0.7 < C < 1.6 in the BMSS M Star Catalog IRAS NAME 173032955
Sp.Type M8
m12 2 .09 2 .43 1 .99 2 .34 3 .02
C 1.10
17317-2947
M6
17326-2852
M6.5
17329-2848
M7
17334-2903
M6.5
17336-2830
M6.5
17338-2953
M7
17344-2918
M6.5
17362-2830
M7
17364-2845
M5
17374-2847
M7
1 .34
1.01
17377-2859
M7
2.1
0.94
17393-2913
M8
17399-2811
M6.5:
17463-2946
M8
17470-2959
M6
2 .67
0.72
17479-2927
M7
-0.94
1.20
17131-3521
M6.5
17142-3446
M7
17147-3533
M7
3.3 1 .28 1 .48
17154-3407
M6.5
17159-3459
M7
17212-3258
M7
17214-3546
M7:
17214-3251
M7
1.4 2 .55 1 .56 1 .53 2 .02
17215-3622
M7
17218-3631
M6.5
17219-3207
M8
17228-3301
M7
2 .18 1 .55 2 .38 1 .98 1 .89
1 .31 1 .00 1 .88
1 .45 2 .48 2 .14 1
0.88 1.09 0.96 1.07 0.71 1.30 0.70 0.83 0.71
0.78 0.95 0.94
M12 -12.2 8 -11.6 0 -12.2 5 -11.8 5 -12.1 9 -11.0 8 -12.8 9 -11.0 5 -11.4 5 -11.0 8 -12.0 0 -11.7 9 -11.2 9 -11.8 2 -11.7 9
d (kpc)
Ik
(R - I)k
A rk
MIk
7.5
-
-
-
-
6.4
12.3
-
-
-
7.0
9.4
4.4
-9.2
6.9
11.4
-
-
-
11.0
12.3
-
-
-
3.1
4.5
9.8
3.2
4.7
-8.2
7.7
10.5
2.8
<3.5
>-7.4
4.9
10.8
-
-
-
4.9
12.2
-
-
-
3.9
9.9
4.7
-7.8
4.7
11.4
-
-
-
6.0
11
-
-
-
3.3
10.5
-
-
-
3.7
12.6
-
-
-
5.4
11.2
1.8
5.7
11.3
1.8
3.0
< 0.6
>-3.0
2.1
9.3:
3.7:
0.94
-11.1 1 -12.5 9 -11.79
10.4
12.2
0.79
-11.32
3.3
11.3
1.14
-12.40
6.0
9.1
3.8
<6.4
0.87
-11.57
3.9
7.8
3.3
5.0
-10.2
0.84
-11.48
6.4
11.3
-
-
-
0.73
-11.14
3.5
11.4
-
-
-
0.83
-11.45
3.9
13.3
-
-
-
1.05
-12.12
6.7
13.:
-
-
-
1.07
-12.19
5.3
9.6
3.3
<5.0
0.9
-11.66
6.7
9.2
3
4.1
0.92
-11.72
5.9
12
1.03
-12.06
6.4
11.6
0.9
-3.4
-
< 6.2 -
-
-
-
-
>-8.3
>-11.2
>-9.0 -9.0
.97 2 .92
17233-3238
M6.5:
1.20
-12.59
12.6
12.7
17238-3212
M6.5
0.91
-11.69
7.7
12.6
17244-3628
M8
0.85
-11.51
3.7
10.:
17255-3142
M7
1.02
-12.03
7.7
11.6
-
-
-
17261-3139
M6
1.33
-12.98
19.1
12.5
1.3
?
?
17265-3109
M6.5
1.18
-12.3
10.3
10.4
3.0
4.1
-8.8
17267-3146
M8
0.94
-11.79
4.4
10
3.4
< 5.3
>-8.5
17271-3635
M7
0.93
-11.75
5.4
12
-
-
-
17272-3243
M6.5
1.26
-12.77
8.9
>13. 4
-
-
-
17275-3423
M6.5
0.77
-11.26
3.5
9
3.6
5.9
-9.6
17277-3653
M8
1.53
0.84
-11.48
4.0
10.1
3.1
< 4.4
>-7.3
17283-3645
M6.5
1.6 1 .43
1.05
-12.12
5.6
10.9
2.3
?
?
17284-3655
M7
0.76
-11.23
3.4
11.2
-
-
-
17285-3533
M7
2.79
-11.36
6.7
10.9
-
-
-
17286-3307
M7
1.86
-11.63
5.0
11.8
-
-
-
17286-3505
M7
1.92
-11.66
5.2
12
-
-
-
17286-3611
M7
1.35
0.92
-11.72
4.1
9.2
3.5
2.14 2.31 2.03 3.04
1.15 1.17 0.78 0.86
-12.4 -12.4 -11.29 -11.54
8.2 9.1 4.6 8.2
11.1 13 11.4 11.3
-
< 5.6 -
17287-3048 17291-3331 17292-3259 17293-3653
M8 M7: M7 M6.5
17295-3200 173043628 173073321 173083502 173093408
M8
2.97
1.02
-12.03
10.0
11.6
-
-
-
M7:
3.77
1.25
-12.74
20.0
13
-
-
-
M8
2.07
0.92
-11.72
5.7
10.6
3.5
<5.6
>-8.8
M6
1.12
0.95
-11.82
3.9
8.9
3.6
6.2
-10.2
M7
2.77
0.76
-11.23
6.3
11.0
2 .73 1 .34 2.4 3 .42 2 .55 1 .41 1 .92 1 .98 1 .44
0. 8 0.89 0. 9
-
-
>-9.5 -
-
Table 3-2 (continued). Late-IPS/M stars with 0.7 < C < 1.6 in the BMSS M Star Catalog
IRAS NAME 17310-3108 17311-3458 17313-3551 17315-3530 17316-3301
Sp.Type M8 M7 M7: M6.5 M7
m12
C
1.23 1.12 3.22 1.58 2.37
0.7 1.11 0.71 1.03 1.06
M12
d (kpc)
-11.05 -12.31 -11.08 -12.06 -12.15
2.9 4.85 7.2 5.4 8.0
Ik 12.7 10.5 12.0: 9.8 11.7
(R - I)k 3.8
A rk 6.5 -
MI k -10.3 -
17321-3053
M8
17321-3336
M6
17321-3457 17324-3520 17326-3424
M6.5: M7 M6.5
17327-3534
M6.5
17327-3411
M7:
17332-3332
M8
17337-3519
M7
17341-3403
M6.5, M7
17341-3453
M5
17343-3425
M6.5, M6.5
17345-3337
M7
17350-3459
M5:
17351-3431
M7
17352-3350
M8
17354-3455
M7
17357-3404
M6, M6.5
17360-3300
M8
17364-3428
M6.5, M7
17365-3126
M6.5
17366-3129
M7
17367-3341
M8
17367-3431
M6.5
17370-3311
M7
17371-3244
M7
17377-3224
M7
17378-3411
M6.5
17379-3019
M7
17383-3112
M6.5
17386-3018
M6.5
17386-3035
M6.5
173873225
M7
1.06 -0.1 1 3.13 1.2 1.11 2 .68 2 .49 0 .67 2 .14 2 .52 -2.0 2 2 .35 3 .71 0 .36 3 .15 2 .24 -0.3 1 2 .47 1 .64 2 .58 1 .33 2 .43 1 .59 1 .71 1 .72 1 .51 0 .34 2 .03 -1.68 2 .36 1 .09 2 .59 3 .12
0.88
-11.60
3.4
11.6
-
-
-
1.1
-12.28
2.7
<7.2
R=7.8
-
-
1.21 1.27 0.99
-12.62 -12.80 -11.94
14.1 6.3 4.1
11.9 11.2 8.1
3.4
-
-10.3
0.83
-11.45
6.7
10.9
-
-
-
0.96
-11.85
7.4
12.1
-
-
-
0.77
-11.26
2.4
10.3
3.9
0.73
-11.14
4.5
11.9
-
0.89
-11.63
6.8
9.6, 9.7
3.3, 2.6
1.21
-12.62
1.3
<7.2
R=8.2
-
0.91
-11.69
6.4
10.5, 9.4
3.0,4. 1
4.1, 7.3
1.07
-12.18
15.1
11.8
-
-
-
0.88
-11.60
2.5
11.7
-
-
-
0.89
-11.63
9.0
12.8
-
-
-
0.93
-11.75
6.3
11.8
-
-
-
0.92
-11.72
1.9
7.4
3.3
<5.0
0.88
-11.60
6.5
11.3, 11.1
3.0
4.1
0.77
-11.26
3.8
11.4
-
0.95
-11.82
7.6
10
2.6
<2.9
1.12
-12.34
5.4
8.5
3.2
4.7
0.94
-11.79
7.0
12
-
0.75
-11.20
3.6
9.8
3.6
0.98
-11.91
5.3
9.8
-
-
-
1
-11.97
5.5
10.5
-
-
-
1.04
-12.09
5.3
12.2
0.75
-11.20
2.0
11.7
1.05
-12.12
6.8
-
1.29
-12.86
1.7
13
0.83
-11.45
5.8
12.7
0.92
-11.72
3.7
10.5
1.53
-13.60
17.3
11.6
1.07
-12.19
11.5
12
5.3
<6.7 -
>-8.3 -
5.0,3. 0
-9.6, -7.5 -
-
-7.6, -11.9
>-9.0 -6.7 -
<5.9
>-7.3 -9.9 >-8.9
173923234 173943305 174023137 174083252 174093309 174143053 174193237 174203128 174273118 174453128 174483042 174493013 174513028 174563045 174643053
M7: M7
2 .42 2 .93
0.85
-11.51
6.1
12.9
0.96
-11.85
9.0
12.1
M7
1 .52
0.76
-11.23
3.6
13.3
M7
0.85
1.11
-12.31
4.3
12.9
M6
2.58
0.99
-11.94
8.0
11.7
M6.5
1.97
0.78
-11.29
4.5
11.7:
M8
0.87
0.76
-11.23
2.6
12.5
M6.5
2.32
1.15
-12.43
8.9
13.5
-
-
-
M7
1.51
0.75
-11.20
3.5
11.6:
-
-
-
M6.5
0.32
1.25
-12.74
4.1
>13. 9
-
-
-
M8
2.22
1.07
-12.19
7.6
10
1.5:
?
?
M7
1.41
0.89
-11.63
4.1
9.1
2.8
<3.5
>-7.4
M8
1.02
0.77
-11.26
2.9
9.8
-
-
M7
3.03
0.96
-11.85
9.5
12
-
-
M6.5
2.97
1.06
-12.15
10.6
10.7
2.6
2.9
-7.3
Explanation of Table 3-1 and Table 3-2: Column 1: IRAS Name (Beichman et al., 1987). Column 2: Spectral type in the Case system Columns 3 and 4: Apparent magnitude at 12 µm, m12, and IR color, C= m12 – m25. Column 5: Absolute magnitude at 12 µm, M12. Column 6: Estimated Distance (in kpc) d = 10 {(m12-M12+5)/5} pc Column 7 and 8: observed I k magnitude in Kron system and observed color (R– I) k in Kron system. Column 9 : Estimated extinction in the I k band. For M star later than M6.5, it is assumed that (R–I) 0 k > 1.6, A(I k )= 2.93 E(R–I) k ; E(R–I) k = (R–I) k – (R–I) 0 k Column 10: Absolute magnitude in I Kron system. MI k = – (m12 – M12) + I k – A(I k )
K & M giants: Kinematics and photometric properties of galactic K and M giants The distribution of IRAS Point Sources (IPS) according to the IR color, C, [ C = m12– m25 = –2.5 log (F12/F25) + 1.56 where F12 and F25 flux density at 12 micron and 25 micron respectively, expressed in Janskies ], showed a bimodal distribution of InfraRed stars (IR stars) with a maximum at C = 0.0 and C = 0.7. Those IR stars with C = 0.0 generally identified as K and M giants stars in bright star Catalogue. The kinematics properties of those stars, solar motion component to galactic centre direction Uo, galactic rotation Vo and perpendicular to U-V plane, Wo obtained by using astrometry data of Hipparcos Catalogue, tend to have larger value than main sequence dwarf stars. The aim is to study of galactic structure based on K and M giant stars with the IRAS Point Sources and the Hipparcos Catalogues counterparts. From IRAS catalogue (245889 objects), we can get information: Position (RA,DEC) & (l,b), IRAS Number, F12 & F25 (Flux density at 12 and 25 micron, expressed in Jankies), and FQ12 & FQ25 (Flux Quality, 3=high, 2=moderate, and 1=bad). And from Hipparcos catalogue (118218), we can get: Position, Parallax, Proper motion, B, V, B-V, V-I, and Spectral type. The IRAS objects have counterparts with the Hipparcos objects based on position coincided within 10”. From 245,889 stars of the IRAS Point Sources Catalogue, we choose 71,567 stars with the criteria FQ12=FQ25=3 (high quality data). This is the first basic data. We made fig. 1: our galaxy −the Milkyway, fig. 2: bimodal distribution, fig. 3 and fig. 4. From fig. 3 and fig. 4, we can see that at C=m12−m25 near zero, the objects fill all over longitude and latitude of the Milkyway. Begin with the IRAS data and with criteria C=m12−m25 < 0.15 (for K and M giant stars) [Raharto, et al.], we obtained 9320 objects. The IRAS objects have counterparts with the Hipparcos objects based on position coincided. We obtained 6148 objects. Finally we only choose the objects with K and M spectral types, and we obtained 5206 objects. This is the second basic data. From this data we made figures and graphics: (l,b) of K and M giants, distance (K and M giants) vs Proper motion. Distribution of m12, m25, V , and distance of K and M giant stars, and V-I vs. B-V. The criteria C < 0.15 for searching the K and M giant stars is the best approximation because we can obtain 5206 the K and M giant stars of 6148 objects from this criteria or with accuracy about 85%. The K and M giant stars are good objects for study of galactic structure because the distribution of these objects are almost homogen in our galaxy, the Milkyway Galaxy. The Hipparcos catalog which contains astrometry data of about 100,000 stars with high accuracy (σπ/π < 0.1 for parallax) and a precision of 1 miliarcsecond for proper motion are used to derive the solar motion. The catalog also contains spectroscopic, radial velocity, and photometric data with a limiting magnitude of V= 12.4. Distribution of stars is relatively uniform for all galactic longitudes within the distance of 100 parsecs, while for 200 parsecs and more an asymmetry is seen and tends to be distributed between l = 270° to 360°. In general, the spectral types are dominated by K-giant stars. Kinematic studied solar motion based on K and M giants stars with less precise (σπ/π < 0.2) data obtained U0 = 9.47 km/sec, V0 = 20.8 km/sec, and W0 = 7.83 km/sec Laksmana & Raharto (2006). These results have similar tendency with those obtained by Famaey et al. (2005).
Wiramihardja et al. (2006) using formula –Uo cos b cos l – Vo cos b sin l – Wo sin b = VR , and So = (Uo2 + Vo2 + Wo2)1/2 ( where Uo is a component of solar motion to the galactic centre direction, Vo is component of solar motion in the direction of galactic rotation and Wo is component of solar motion perpendicular to the U-V plane, l = galactic longitude and b = galactic latitude, VR is radial velocity, d = distance to the stars, μl = proper motion in the direction of the galactic longitude and μb = proper motion in the direction of galactic latitude, So is solar motion relative to the Local Standard of Rest ) we obtained velocity component of solar motion Uo = –10.96 km/s; Vo = 18.44 km/s and Wo = 8.93 km/s and solar motion So = 23.34 km/s and apex, the direction of solar motion is l = 59º.29 and b = 22º.60. With more stars of about 15,000 and using formula Uo sin b cos l + Vo sin b sin l – Wo cos b = d μb and Uo sin l – Vo cos l = d μl cos b; we obtain Uo = –9.30 km/s; Vo = 5.14 km/s and Wo = 5.73 km/s, So = 12.23 km/s and apex direction of solar motion is l = 28º.91 and b = 28º.33. The difference might be arising from kinematical bias, i.e., the radial velocity observations could not detect very small values of radial velocity of stars. Prianto, Ningsih and Raharto (2005) notice that wider range of variation in the values of solar motion components of dwarf, subgiant and giant stars partly due to large range differs of stellar age. The largest discrepancies from the mean showed by M spectral type with luminosity class of giants and dwarfs. It is probably due to the old age and small sample of stars. For K0 giant stars, large value for v_ component agrees with Zhu & Jin (2000) – ZJ who found 21.45±0.32 km/s, but values of other components differ significantly. ZJ used proper motion data to yield these values and secondly ZJ used larger number of stars (23,181 stars) compared to our samples. Results for solar motion are also provided by Dehnen & Binney (1998) – DB and Bienaymˆe who obtained: u_ = 9.7 ± 0.3 km/s, v_ = 5.2 ± 1.0 km/s, w_ = 6.7 ± 0.2 km/s (Bienaymˆe) and u_ = 10.0 ± 0.36 km/s, v_ = 5.25 ± 0.62 km/s, w_ = 7.17±0.38 km/s (DB). Our mean results show the same direction of solar motion, that is: radially inwards (u_), in the direction of galactic rotation (v_) and vertically upwards (w_). The differences in number of stars and method used in calculation might cause the large discrepancies in v_ values, but according to DB, values of v_ for dwarf stars with different B-V varied from 9 to 25 km/s. For w_ component value, it is probable that the discrepancy is caused by the dominant number of old stars in sample of stars used in calculation. Sugianto and Raharto (2006) provide two color diagram (V – I) and (B – V) f of K and M giants stars presented in Figure 2. There are two branches in the two color diagram locus in (B – V) ≈ 1.5, one is locus in (B – V) ≈ 1.7 parallel to main straight line due to reddening of interstellar extinction, the second branch is almost perpendicular to the main straight line may be due to reddening of circumstellar dust and evolutionary stage of the stars.
Figure 11
Figure 2: Two color diagram V – I and B – V for K and M giants, it is clearly seen that circumstellar dust an important role for photometric reddening of stars with circumstellar dust. The distribution of IRAS Point Sources (IPS) according to the IR color, C , C = m12–m25 = –2.5 log (F12/F25) + 1.56, where F12 and F25 are flux densities at 12 micron and 25 micron respectively, expressed in Janskies, showed a bimodal distribution of Infra Red stars (IR stars) with a maximum at C = 0.0 and C = 0.8. Those IR stars with C < 0.15 generally identified as K and M giant stars in Bright Star Catalogue. The K and M giant stars are good objects for study of galactic structure because the distribution of these objects almost homogenous in our galaxy, the Milkyway. The limiting magnitude m12, m25, and V observation of K and M giants stars are 4.5, 5.0, and 11.5 mags respectively. It corresponds to the limiting distance d of 1.5 kpc. EPILOGUE Optical M stars survey in limited region of galactic plane and closed to galactic centre was one of the astronomical cooperation between Japan and Indonesia in period of 1979 – 1984, meanwhile global sky survey in IR such IRAS, ISO and ground based survey such as TMSS as well as makes a large amount of data available. There are remain a lot of astronomical problem in which can be explored in astronomical cooperation of cool stars in the Galaxy. The progress of electronic detector and internet speed up and change the shape of astronomical observation and astronomical cooperation. More man power and more money are necessary to work out beside the realistic astronomical cooperation plan.
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