1. The Near-Infrared Extinction Laws and Distance Estimation of Monoceros Nebula
He Zhao Biwei Jiang

2. Monoceros Nebula SNR G205.5+00.5 Glon/deg 205.73 Glat/deg 0.21
RA J2000/h:m:s
DEC J2000/d:m:s
MajDiam/arcmin
220
Type S

5. Data
Lamost-xuyi
APOGEE
<Allen’s Astrophysical Quantities>

6. Giants spectral type G5 G8 K0 K2 K5 M0 M2 M5 Mv 0.9 0.8 0.7 0.5 -0.2
-0.4
-0.6
-0.3
Teff
5050
4800
4660
4390
4050
3690
3540
3380
Spectral type G4 G6 G8 K0 K1 K2 K3 K4 K5 M0 M1 M2 M3
V-K
2.05
2.15
2.16
2.31
2.5
2.7 3
3.26
3.6
3.85
4.05
4.3
4.46
Teff
5190
5050
4960
4810
4610
4500
4320
4080
3980
3820
3780
3710
3630
J-H
0.47
0.5
0.54
0.58
0.63
0.68
0.73
0.79
0.83
0.85
0.87
0.9
H-K
0.08
0.09
0.1
0.12
0.14
0.15
0.17
0.19
0.21
0.22
0.24
J-K
0.55
0.59
0.64
0.75
0.82
0.88
0.96
1.02
1.06
1.09
1.14

7. Main-sequences spectral type F0 F2 F5 F8 G0 G2 G5 G8 K0 K2 K5 M0 M2 Mv
2.7
3.6
3.5 4
4.4
4.7
5.1
5.5
5.9
6.4
7.35
8.8
9.9
Teff
7300
7000
6650
6250
5940
5790
5560
5310
5150
4830
4410
3840
3520
spectral type A7 F0 F2 F5 F7 G0 G2 G4 G6 K0 K2 K4 K5 K7 M0 M1 M2
V-K
0.5
0.7
0.82
1.1
1.32
1.41
1.46
1.53
1.64
1.96
2.22
2.63
2.85
3.16
3.65
3.87
4.11
Teff
7930
7020
6750
6530
6240
5930
5830
5740
5620
5240
5010
4560
4340
4040
3800
3680
3530
J-H
0.09
0.13
0.17
0.23
0.29
0.31
0.32
0.33
0.37
0.45
0.58
0.61
0.66
0.67
H-K
0.03
0.04
0.05
0.06
0.08
0.11
0.15
0.18
0.2
J-K
0.12
0.16
0.21
0.27
0.34
0.36
0.39
0.43
0.53
0.59
0.69
0.72
0.81
0.84
0.86

8. Data Selection Condition： σJHKs<0.05，σTeff<300 K，σlog g<0.5，
For Main-sequences：Teff【3500,8000】，log g >4.0，Z>-0.5，|b|<10.0
For Giants：Teff【3600,6000】，
0.5<log g <3.0，Z>-0.5，|b|<10.0
Lamost-xuyi
APOGEE
Star-type
Main-sequence
Giant
Amount
16268
1231
14251

9. Lamost-xuyi Crossed Data

10. APOGEE Data

11. Data Selection in Monoceros Nebula
Lamost-xuyi
APOGEE
Star-type
Main-sequence
Giants
Amount
196 9 22

12. Method Part Ⅰ
Part Ⅰ: Color Excess Ratio and Extinction

13. All in all, calculating color excess ratio and
extinction, what we have to do is to find the relation between intrinsic color index and effective temperature.

14. The relation between intrinsic color index and effective temperature
Firstly, we divided the range of temperature into 20 bins. Each bin is further divided into 10 secondary bins according to color index value;
Secondly, we select the bluest point in the bin which appears with the value greater than a third of the highest frequency. And the relation between intrinsic color index and effective temperature is fitted according to those 20 points;
Finally, estimation of error is made through comparing the fitted curve and data points given by Allen.

15. Lamost-xuyi

16. APOGEE

17. Main-sequence stars [3500K~8000K]
The red line marks the position of the selected points.

18. The average of the error between fitted curve and data points from Allen is 0.0476

20. Giants [3600K~5200K]

21. The average of the error between fitted curve and data points from Allen is 0.0302

23. Method Part Ⅱ Part Ⅱ: Distance Estimation
The relations between and Teff、 and Teff are fitted by data points given by Allen

24. The relation between V-band absolute magnitude and effective temperature

26. The relation between intrinsic color (V-K) and effective temperature

28. Photometric Error/Ave Photometric Error/Ave
For Main-sequences
Photometric Error/Ave
Fitted Error/Ave
J-H
0.0358
0.0126
H-K
0.0367
0.0170
J-K
0.0350
0.0155
For Giants
Photometric Error/Ave
Fitted Error/Ave
J-H
0.0356
0.0054
H-K
0.0341
0.0225
J-K
0.0326
0.0502
这里的Fitted Error指的是曲线按照测光误差平移之后与Allen所给的点的误差的平均值

29. Results:
For Main-sequences:

30. For Giants:

31. Distance vs. J-band Extinction

34. Color Excess Raito (Only contains Giants)

37. E(J-H)/E(J-K)+E(H-K)/E(J-K)
Monoceros Nebula
Galaxy ISM
E(J-H)/E(J-K)
0.63
0.64
E(H-K)/E(J-K)
0.37
0.36
E(J-H)/E(H-K)拟合值
1.12
1.78
E(J-H)/E(J-K)+E(H-K)/E(J-K)
1.00
E(J-H)/E(H-K)计算值
1.70
1.68
The values of color excess ratio in Galaxy ISM comes from (Wang&Jiang2014)

38. Discussion about Distance and
Stars have so small J-band extinction:
For main-sequences, intrinsic color index we got may be greater than the true. Or the data we use may have problems.
For giants, actually, there is no good relation between V-band absolute magnitude and effective temperature. Giants from APOGEE data may be not so distant from us as we see in the figure.

41. We can see no obvious increases around the Nebula :
We don’t have enough faraway sources and we get wrong distances of Giants.
The relation between intrinsic color index and effective temperature.
The method to get accurate absolute magnitude.

43. Summary
So far, we can see no obvious increases around Monoceros Nebula;
The near-infrared extinction laws of Monoceros Nebula is similar to Galaxy ISM;
So much more work has to be done…

46. The average of the error between fitted curve and data points from Allen is 0.0197

49. The average of the error between fitted curve and data points from Allen is 0.0505

52. The average of the error between fitted curve and data points from Allen is 0.0566

55. The average of the error between fitted curve and data points from Allen is 0.0828