臺灣博碩士論文加值系統

Comets are thought to be pristine relics from the birth of our Solar System and they have experienced the least thermal alteration. Comets, in particular long-period ones, thus keep the information of the time when they were formed. In spring 2004, the apparitions of two long-period comets C/2001 Q4 (NEAT) and C/2002 T7 (LINEAR), at a distance of 0.3 and 0.27 AU respectively from the Earth at perigee, provided us a rare opportunity to have a detailed study cometary inner coma where photodissociation is ineffective and most cometary parent molecules remain.
We successfully imaged the spatial distribution of CS and CH3OH of C/2002 T7 (LINEAR) using the Submillimeter Array (SMA). Detailed analysis of SMA images of Comet/T7 suggests strongly that methanol molecules are sublimated directly from the cometary nucleus. Earlier studies implied that CS is a daughter molecule of CS2. Even with our SMA observations at 1500×900 km high-linear resolution, however, we were not able to discriminate whether CS is a parent or a daughter molecule, i.e., whether the CS molecule seen in the inner coma was directly sublimated from the cometary nucleus or it was produced via photodissociation of CS2 molecule.
Single-dish observations using the Kitt Peak 12m radio telescope (KP12M) were also carried out. Molecular emission of CS, HCN, H2CO in Comet C/2001 Q4 (NEAT), and HCN, H2CO, HDCO and CH3OH in Comet C/2002 T7 (LINEAR) were detected. HDCO has never been detected in any comet previously. The D/H ratio of Comet C/2002 T7 derived is 0.28 based on our measurements of HDCO and H2CO. The high D/H ratio observed is analogous to the values of Class 0 solar-type protostellar sources reported, and therefore implies that the Solar Nebula may have gone through evolutionary stages similar to that of these protostellar sources.

ABSTRACT I
CONTENTS II
LIST OF FIGURES III
LIST OF TABLES V
CHAPTER 1 INTRODUCTION 1
1.1. THE ORIGIN OF COMET 1
1.2. NEBULAR PROCESSES VS. INTERSTELLAR PROCESSES 1
1.3. COMETARY VOLATILES 3
1.4. ISOTOPIC ABUNDANCES IN COMET 5
1.5. COMETS C/2002 T7 LINEAR AND C/2002 Q4 6
CHAPTER 2 OBSERVATIONS 10
2.1. SMA 10
2.2. KP12M 13
CHAPTER 3 RESULTS 17
3.1. SMA: CS AND CH3OH IMAGES OF COMET C/2002 T7 17
3.2. KP12M: DETECTIONS OF CS, HCN, H2CO, HDCO AND CH3OH 18
CHAPTER 4 ANALYSES AND DISCUSSIONS 35
4.1. ROTATIONAL TEMPERATURE 35
4.2. MOLECULAR COLUMN DENSITY 36
4.3. GAS PRODUCTION RATES 39
4.4. HASER MODEL IMAGE 42
4.5. THE EXTENDED SOURCE OF FORMALDEHYDE 47
4.6. THE HIGH D/H RATIO IN COMET/T7 51
CHAPTER 5 SUMMARY 54
BIBLIOGRAPHY 55
APPENDIX A <IZ> SUMMATION PROGRAM 59

A'Hearn, M. F., Millis, R. L., Schleicher, D. G., Osip, D. J., Birch, P. V., The ensemble properties of comets: Results from narrowband photometry of 85 comets, 1976–1992., 1995, Icarus, 118, 223–270

Altwegg, K., Bockelee-Morvan, D., Isotopic Abundances in Comets, 2003, Space Science Reviews, 106, 139–154

Biver, N., Bockelee-Morvan, D., Crovisier, J., Colom, P., Henry, F., Moreno, R., Paubert, G., Despois, D., Lis, D. C., Chemical Composition Diversity Among 24 Comets Observed At Radio Wavelengths, 2002, Earth Moon and Planets, 90, 323–333

Biver, N., Bockelee-Morvan, D., Crovisier, J., Davies, J. K., Matthews, H. E., Wink, J. E., Rauer, H., Colom, P., Dent, W. R. F., Despois, D., Moreno, R., Paubert, G., Jewitt, D., Senay, M., Spectroscopic Monitoring of Comet C/1996 B2 (Hyakutake) with the JCMT and IRAM Radio Telescopes, 1999, Astronomical Journal, 118, 1850–1872

Blake, G. A., Qi, C., Hogerheijde, M. R., Gurwell, M. A., Muhleman, D. O., Sublimation from icy jets as a probe of the interstellar volatile content of comets, 1999, Nature, 398, 213

Bockelee-Morvan, D., Crovisier, J., Mumma, M. J., Weaver, H. A., The composition of cometary volatiles, 2004, Comets II, 391–423

Bockelee-Morvan, D., Gautier, D., Lis, D. C., Young, K., Keene, J., Phillips, T., Owen, T., Crovisier, J., Goldsmith, P. F., Bergin, E. A., Despois, D., Wootten, A., Deuterated Water in Comet C/1996 B2 (Hyakutake) and Its Implications for the Origin of Comets, 1998, Icarus, 133, 147–162

Charnley, S. B., Ehrenfreund, P., Kuan, Y.-J., Spectroscopic diagnostics of organic chemistry in the protostellar environment, 2001, Spectrochimica Acta, 57, 685–704

Crovisier, J., Bockelee-Morvan, D., Remote Observations of the Composition of Cometary Volatiles, 1999, Space Science Reviews, 90, 19–32

Crovisier, J., Photodestruction rates for cometary parent molecules, 1994, Journal of Geophysical Research, 99, 3777–3781

Eberhardt, P. Volatiles, isotopes and origin of comets. In Asteroids, Comets, Meteors 1996, COSPAR Colloquium 10

Ehrenfreund, P., Charnley, S. B., Organic Molecules in the Interstellar Medium, Comets, and Meteorites: A Voyage from Dark Clouds to the Early Earth, 2000, Annual Review of Astronomy and Astrophysics, 38, 427–483

Friedel, D. N., Remijan, A. J., Snyder, L. E., A'Hearn, M. F., Blake, G. A., de Pater, I., Dickel, H. R., Forster, J. R., Hogerheijde, M. R., Kraybill, C., Looney, L. W., Palmer, P., Wright, M. C. H., BIMA Array Detections of HCN in Comets LINEAR (C/2002 T7) and NEAT (C/2001 Q4), 2005, Astrophysical Journal, 630, 623–630

Gensheimer, P. D., Mauersberger, R., Wilson, T. L., Water in galactic hot cores., 1996, Astronomy and Astrophysics, 314, 281–294

Gladman, B., The Kuiper Belt and the Solar System's Comet Disk, 2005, Science, 307, 71–75

Greenberg, J. M., Making a comet nucleus, 1998, Astronomy and Astrophysics, 330, 375–380

Greenberg, J. M., What are Comets Made of - Very Dirty Snowballs, 1982, Interstellar Comets Workshop, 24

Haser, L., Distribution d'intensite dans la tete d'une comete, 1957, Bulletin de la Societe Royale des Sciences de Liege, 43, 740–750

Hatchell, J., Bird, M. K., van der Tak, F. F. S., Sherwood, W. A., Recent searches for the radio lines of NH3 in comets, 2005, Astronomy and Astrophysics, 439, 777–784

Hatchell, J., Millar, T. J., Rodgers, S. D., The DCN/HCN abundance ratio in hot molecular cores, 1998, Astronomy and Astrophysics, 332, 695–702

Hagemann, R., Nief, G., Roth, E., Absolute isotopic scale for deuterium analysis of natural waters. Absolute D/H ratio for SMOW, 1970, Tellus, 22, 712
Huebner, W. F., Keady, J. J., Lyon, S. P., Solar photo rates for planetary atmospheres and atmospheric pollutants, 1992, Astrophysics and Space Science, 195, 1–289

Irvine, W. M., Schloerb, F. P., Crovisier, J., Fegley, B., Jr., Mumma, M. J., Comets: a Link Between Interstellar and Nebular Chemistry, 2000, Protostars and Planets IV, 1159

Jackson, W. M., Halpern, J. B., Feldman, P. D., Rahe, J., Production of CS and S in Comet Bradfield 1979/X, 1982, Astronomy and Astrophysics, 107, 385-389

Kuan, Y.-J., Charnley, S. B., Huang, H.-C., Tseng, W.-L., Kisiel, Z., Interstellar Glycine, 2003, Astrophysical Journal, 593, 848–867

Lecacheux, A., Biver, N., Crovisier, J., Bockelee–Morvan, D., Comet C/2001 Q4 (NEAT), 2004, International Astronomical Union Circular, 8304, 2

Lissauer, J. J., Planet formation, 1993, Annual Review of Astronomy and Astrophysics, 31, 129–174
Lunine, J. I., The Urey Prize Lecture - Volatile processes in the outer solar system, 1989, Icarus, 81, 1–13

Mahaffy, P. R., Donahue, T. M., Atreya, S. K., Owen, T. C., Niemann, H. B., Galileo Probe Measurements of D/H and 3He/4He in Jupiter's Atmosphere, 1998, Space Science Reviews, 84, 251–263

Meier, R., Owen, T. C., Jewitt, D. C., Matthews, H. E., Senay, M., Biver, N., Bockelee-Morvan, D., Crovisier, J., Gautier, D., Deuterium in Comet C/1995 O1 (Hale-Bopp): Detection of DCN, 1998a, Science, 279, 1707

Meier, R., Owen, T. C., Matthews, H. E., Jewitt, D. C., Bockelee-Morvan, D., Biver, N., Crovisier, J., Gautier, D., A Determination of the HDO/H2O Ratio in Comet C/1995 O1 (Hale-Bopp), 1998b, Science, 279, 842

Messenger, S., Walker, R. M., Evidence for Molecular Cloud Material in Meteorites and Interplanetary Dust, 1997, American Institute of Physics Conference Series, 402, 545
Mumma, M. J., Disanti, M. A., dello Russo, N., Magee-Sauer, K., Gibb, E., Novak, R., Remote infrared observations of parent volatiles in comets: A window on the early solar system, 2003, Advances in Space Research, 31, 2563–2575

Mumma, M. J., Weissman, P. R., Stern, S. A., Comets and the origin of the solar system – Reading the Rosetta Stone, 1993, Protostars and Planets III, 1177–1252

Parise, B., Ceccarelli, C., Tielens, A. G. G. M., Castets, A., Caux, E., Lefloch, B., Maret, S., Testing grain surface chemistry : a survey of deuterated formaldehyde and methanol in low-mass Class 0 protostars, 2006, Astronomy and Astrophysics, 453, 949–958

Pen, M.-L., NTNU M.S. Thesis “The interferometeric study of Hale-Bopp C/1995 O1: CS and CO”, 2001

Sault, R. J., Teuben, P. J., Wright, M. C. H., A Retrospective View of MIRIAD, 1995, ASP Conf. Ser. 77: Astronomical Data Analysis Software and Systems IV, 77, 433

Snyder, L. E., Veal, J. M., Woodney, L. M., Wright, M. C. H., Palmer, P., A'Hearn, M. F., Kuan, Y.-J., de Pater, I., Forster, J. R., BIMA Array Photodissociation Measurements of HCN and CS in Comet Hale-Bopp (C/1995 O1), 2001, Astronomical Journal, 121, 1147–1154

Sorrell, W. H., Origin of Amino Acids and Organic Sugars in Interstellar Clouds, 2001, Astrophysical Journal, 555, L129–L132

Sutton, E. C., Peng, R., Danchi, W. C., Jaminet, P. A., Sandell, G., Russell, A. P. G., The distribution of molecules in the core of OMC-1, 1995, Astrophysical Journal Supplement Series, 97, 455–496

Turner, B. E., A molecular line survey of Sagittarius B2 and Orion-KL from 70 to 115 GHz. II – Analysis of the data., 1991, Astrophysical Journal Supplement Series, 76, 617–686
Van Dishoeck, E. F., Blake, G. A., Chemical Evolution of Star-Forming Regions, 1998, Annual Review of Astronomy and Astrophysics, 36, 317-368

Van Dishoek, E. F., Blake, G. A., Draine, B. T., Lunine, J. I., The chemical evolution of protostellar and protoplanetary matter, 1993, Protostars and Planets III, 163–241

Veal, J. M., Ph.D. Thesis “A millimeter wavelength interferometric study of organic molecules in comet Hale-Bopp”, 2000

Weissman, P. R., The Kuiper Belt, 1995, Annual Review of Astronomy and Astrophysics, 33, 327–358

Yamamoto, T., Ashihara, O., Condensation of ice particles in the vicinity of a cometary nucleus, 1985, Astronomy and Astrophysics, 152, L17–L20

Zinner, E., Presolar Material in Meteorites: an Overview, 1997, American Institute of Physics Conference Series, 402, 3