- Email: [email protected]
2012 S1 (ISON)
Planetary and Space Science 96 (2014) 114–119
Contents lists available at ScienceDirect
Planetary and Space Science journal homepage: www.elsevier.com/locate/pss
The impending demise of comet C/2012 S1 (ISON) Ignacio Ferrín Institute of Physics, Faculty of Exact and Natural Sciences, University of Antioquia, Medellin 05001000, Colombia
art ic l e i nf o
a b s t r a c t
Article history: Received 20 October 2013 Received in revised form 7 March 2014 Accepted 10 March 2014 Available online 21 March 2014
We present evidence to conclude that it is very probable that comet C/2012 S1 (ISON) will disintegrate before reaching perihelion. Figs. 1 and 7 of this work are particularly revealing. The comet is following the path of disintegrating comets and not the path of normal Oort Cloud comets, suggesting that C/2012 S1 (ISON) is going to disintegrate. Note: the comet disintegrated on November 13th, according to this prediction while this paper was being refereed (CBET 3731). & 2014 Elsevier Ltd. All rights reserved.
Keywords: Comets Comet C/2012 S1 (ISON)
1. Secular light curves of comets In a series of papers we have been developing the concept of Secular Light Curves of Comets (SLCs) (Ferrín, 2005, 2006, 2007, 2008, 2009, 2010), a scientific way to show the brightness history of a comet. In this work the SLCs are presented as the reduced magnitude vs log of the Sun's distance, R. Reduced means that the comet–Earth distance has been removed and only the dependence on the distance to the Sun remains. In this work we adopt the envelope of the dataset as the correct interpretation of the observed brightness. There are many physical effects that affect comet observations. All these effects diminish the captured photons coming from the comet, and the observer makes an error downward, toward fainter magnitudes. There are no corresponding physical effects that could increase the perceived brightness of a comet. Thus the envelope is the correct interpretation of the data. The envelope represents an ideal observer, with an ideal telescope and detector, in an ideal atmosphere. Although the above is true for the comets considered in this work, it is also recognized that some observers have a personal bias that send the magnitude above or below the envelope. Additionally in some cases the inclusion or exclusion of the tail in the measurement can change the measurement by one or more magnitudes. Fortunately this is not the case at hand, and it can be concluded that the envelope is rather sharp and a better descriptor of the whole magnitude than the mean of the data. 27 SLCs appear in the Atlas of Secular Light Curves of Comets, Version I (Ferrín, 2010). A full interpretation of the SLCs is given there and will not be repeated here. To carry out this investigation we reduced 11844 photometric observations of five comets.
E-mail address: ferrin@fisica.udea.edu.co http://dx.doi.org/10.1016/j.pss.2014.03.007 0032-0633/& 2014 Elsevier Ltd. All rights reserved.
There have been previous renditions of the light curve of a comet (see for example Bobrovnikoff, 1942; Vseksvyatskij, 1964; Meisel and Morris, 1976; Morris, 1994; Kamel, 1992). However they were not “secular light curves, SLCs” in the sense used in this work and in the Atlas. A SLC measures parameters from the plot, combines data from amateur and professionals, corrects for phase effects, does not fold the data at perihelion, uses the envelope to measure whole magnitudes, and plots the nuclear line when available. Fig. 7 and the Atlas show that the “normal” SLC of an Oort Cloud comet is basically composed of two straight lines separated by a Slope Discontinuity Event, SDE. Notice that after the SDE the normal Oort Cloud comet continue increasing in brightness up to perihelion. Disintegrating comets halt their brightness after the SDE and show a dip in magnitude. The value of the dip goes from þ0.0 for comet Hönig to þ1.5 for comet Bressi.
2. The secular light curve of comet C/2012 S1 (ISON) We are interested in creating the SLC of comet ISON to compare it with other comets. The SLCs have been corrected for phase effects. Fig. 1 shows the very odd SLC of comet C/2012 S1 (ISON) using CCD-R magnitudes available in the internet (Green, 2013; Spahr, 2013). Three things are apparent in Fig. 1. First, there is a SDE very clearly defined at a distance of around 4.1 AU pre-perihelion. Second, there is a slight deep in the light curve just after the event with a U-shape. And third, farther in at 2.8 AU the light curve starts to grow again. This “signature” (SDE þdip) was verified in four additional datasets. The dataset from the Minor Planet Center Database of Astrometric observations is presented in Fig. 2. To reduce the
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Fig. 1. The very odd SLC of comet C/2012 S1 (ISON). It exhibits a SDE at about 4.1 AU from the Sun, followed by a dip and an increase in brightness. This behavior is entirely different to the behavior of a normal Oort Cloud comet, shown in Fig. 7, composed of two straight lines of different slope. Data phase corrected. In this and the following plots, negative logs do not mean numbers less than one. Negative logs mean observations before perihelion so all log numbers are positive. From this plot a magnitude of the dip, mR(POST-SDE) mR(PRE-SDE) ¼ þ0.4, can be measured.
Fig. 2. The dataset from the Minor Planet Center Database, contains photometry from astrometric observations. To reduce the vertical dispersion, daily mean values have been calculated. The plot shows the same SDE þ magnitude dip signature than the CCD dataset. Since these are independent datasets, the signature must be real. From this plot a magnitude of the dip, mR(POST-SDE) mR(PRE-SDE) ¼ þ 0.4, can be measured.
vertical dispersion daily means have been calculated. Since these two datasets are independent, this signature must be a real phenomenon. It must be mentioned that the Minor Planet Center database does not specify the filter of the observations. Actually the database is a mixture of CCD-V, CCD-R, CCD-I, sloan r', sloan g', and luminance/unfiltered observations. Accordingly, this database
is not used for any scientific calculation other than detecting and showing the location of the Slope Discontinuity Event. A search for the signature was conducted in a database of 87 comets that are being prepared for the Atlas, Version II. Two instances were found with similar behavior. The first one is comet C/2002 O4 (Hönig). The light curve is shown in Fig. 3. It shows a behavior reminiscent of comet C/2012 S1 (ISON). We see a clear
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Fig. 3. The SLC of comet C/2002 O4 Hönig. This comet exhibits the same SDE signature and the flattening of the light curve. Data for this plot extracted from Sekanina (2002). From this plot a magnitude of the dip, mR(POST-SDE) mR(PRE-SDE) ¼ þ 0.0, can be measured.
Fig. 4. The SLC of comet C/1996 Q1 Tabur. The data set for this plot comes from the ICQ database maintained by Daniel Green (2013). It exhibits the same signature, a SDE þdip, then a maximum and then a disintegration. From this plot a magnitude of the dip, mR(POST-SDE) mR(PRE-SDE) ¼ þ0.17, can be measured.
slope discontinuity event, a flattening of the light curve, an increase, and then the comet disintegrates. A second case was found in the database, that of comet C/1996 Q1 (Tabur). The SLC of this comet can be seen in Fig. 4. Once again we find the same behavior and signature. A well-defined SDE, a dip after the event, a leveling off and then a precipitous decay into disintegration. After this report appeared in the Arxiv.org data repository, Gary Kronk, Anthony Cook and Jacub Cerny have identified four new
members. They are comets C/1999 S4 (LINEAR), C/2010 X1 (Elenin), C/2012 T5 (Bressi), and C/1997 N1 (Tabur) (unconfirmed) (see Table 1). The first three exhibited the same signature and disintegrated. The SLCs of comet LINEAR appears in Fig. 5 and that of comet Bressi is shown in Fig. 6. While this paper was being refereed, two new members have been identified. They are C/2009 R1 (McNaught) (Hergenrother, 2010) and C/2012 K1 (Panstarrs). A paper by Sekanina (1984) contains sparse information on 7 additional comets, so the total
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Table 1 ISON's group (7)(8)(9). #
Comet
01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20
C/2002 C/2012 C/1999 C/2013 C/2009 C/2012 C/2012 C/2012 C/2010 C/1996 C/1897 C/1957 C/1974 C/1953 C/2008 C/1925 C/1887 20D/1913 P/2006 C/1997
O4 T5 S4 V5 R1 V1 S1 K1 X1 Q1 U1 U1 V2 X1 J4 X1 B1 S1 HR30 N1
(Hönig) (Bressi) (LINEAR) (Oukaimeden) (McNaught) (Panstarrs) (ISON) (Panstarrs) (Elenin) (Tabur) (Perrine) ¼ 1897 III (Latyshev-Wild-Burnham) (Bennet) 1974XV (Pajdusakova) 1954 II (McNaught) Headless comet (Ensor) ¼1926 III headless comet (Westphal) (Siding Spring) (Tabur) (unconfirmed)
R (DISIN) [AU]
q [AU]
CODE (0)
1/a ORIGINAL or e (10)
Identifier (1)
(5) 0.88 0.66 0.92 (6) – (4) 0.79 – (11) 0.67 (6) – 0.64 0.93 1.61 1.11 0.98 0.74 0.64 0.63 (2) – 1.43 (3) – –
0.78 0.32 0.77 0.63 0.41 2.09 0.01 1.05 0.48 0.84 1.36 0.54 0.86 0.07 0.45 0.32 0.005 1.25 1.23 0.40
Sþdþ DN þD Sþdþ DN þD Sþdþ DN þD Sþdþ DN Sþdþ DN þD Sþdþ DN þD Sþdþ DN þD Sþd Sþdþ D Sþdþ D D D D D D D D D Sþd D
0.00077249 0.00022724 0.00005451 0.00003227 0.00003180 0.00001928 0.00000852 0.00001807 0.00011071 0.00182608 1.0000000 1.0000000 1.0000000 1.000000 1.000000 1.000000 1.0000000 0.9198301 0.8437940 1.0001344
I. Ferrín J. Cerny G. Kronk I. Ferrín C. Hergenrother I. Ferrín I. Ferrín I. Ferrín A. Cook I. Ferrín Z. Sekanina Z. Sekanina Z. Sekanina Z. Sekanina I. Ferrín Z. Sekanina Z. Sekanina Z. Sekanina I. Ferrín G. Kronk
0. CODE: S ¼Slope Discontinuity Event (SDE); d ¼ dip after SDE; DN¼ Dynamically New; D¼ Disintegrated. Additionally the group has 1.61o R(DIS) o 0.63 AU. 1. After publishing the first manuscript in the Arxiv.org depository, Gary Kronk, Toni Cook and Jacub Cerny (personal communication), discovered four additional members of the group. 2. See Sekanina (1984). 3. All comets in this list are Oort Cloud members, while this comet is periodic, which raises some interesting questions about its origin. Additionally this comet has not disintegrated and it is due to return in 2027. However it exhibits the signature. 4. Hergenrother (2010)has a light curve showing the SDE þdip, while Siichi's web site http://www.aerith.net shows that the comet was not detected post-perihelion, all consistent with disintegration, although this was not observed. 5. Dynamically new comets have been highlighted in black. 6. These two comets exhibit the SDEþ dip signature, but are still far from perihelion and have not yet disintegrated. 7. From Column 3, R(Disintegration), we deduce that there is a R(limit) ¼ 0.63 AU (Pre-perihelion). All comets have disintegrated before reaching this limit. 8. From the next to the last column, it is clear that dinamically new comets have a clear tendency to disintegrate. 9. The SLCs of many of these comets have been presented by Ferrín (2013, 2014) and are not repeated here due to space limitations. 10. In this work we define dynamically new as 1/a(original)o 0.00001000. The 1/a(original) value is given when available. 11. The disintegration distance for comet ISON was determined using data by Ferrín (2013a) and by Combi et al. (2013) (CBET 9266).
Fig. 5. The SLC of comet C/1999S4 LINEAR, exhibits the same signature characteristic of disintegrating comets. This comet was identified by Gary Kronk. The data set for this plot comes from the ICQ database maintained by Daniel Green (2013). From this plot a magnitude of the dip, mR(POST-SDE) mR(PRE-SDE) ¼ þ 0.5, can be measured.
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Fig. 6. The secular light curve of comet C/2012 T5 Bressi shows the same signature as other disintegrating comets. This comet was identified by Jacub Cerny after posting the original paper in the Arxiv.org depository. The data comes from the Minor Planet Center database. From this plot a magnitude of the dip, mR(POST-SDE) mR(PRE-SDE) ¼ þ 1.5, can be measured.
Fig. 7. A comparison is made of Normal Oort Cloud comets with disintegrating comets. Normal Oort Cloud comets show two linear laws separated by a SDE. After the event they continue increasing in brightness up to perihelion. Disintegrating comets stop their brightness increase after the SDE. Shortly after they disintegrate. In view of the fact that comet C/2012 S1 (ISON) is following the path of disintegrating comets and not the path of normal Oort Cloud comets, it is very probable that the comet will disintegrate. The plot shows the envelopes of the comets. Note: While this paper was being refereed the comet disintegrated (CBET 3731).
confirmed members is now 17 (see Table 1). This table gives the distances at which disintegration took place. Finally Fig. 7 shows all the SLCs of these comets plotted together along the SLCs of normal Oort Cloud comets. Normal Oort Cloud comets have SLCs composed of two straight lines separated by the SDE, after which they continue brightening up to perihelion. Disintegrating comets halt their light after the SDE. The fact that we had to correct the SLCs for phase effects implies that the coma is dominated by large particles and that there are
significant quantities of dust. A spectrum of comet C/2012 S1 (ISON) taken by Buil (2013) confirms that there were almost no gas lines, and that the comet was dominated by large particles on that particular date or period around that date (2013, October 11). A bare nucleus like an asteroid has a brightness law behaving as R∧( 2.0). Any slope less than this value implies that the comet is fading. The fact that the comets in Figs. 1–6 exhibit a dip in magnitude after the SDE that goes from þ0.0 for comet Hönig to þ1.5 for comet Bressi, implies that all these comets are fading after
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the SDE. The reason for this fading cannot be addressed in this work, and requires a complex cometary model beyond the scope of this paper. 3. Conclusions (1) Comets of the Oort Cloud announce that they are going to disintegrate by exhibiting the SDE+magnitude dip signature. Of the 13 comets with this signature in Table 1, 13 disintegrated. (2) Additionally, the fact that it is following the path of disintegrating comets and not the path of normal Oort Cloud comets, implies that it is very probable that the comet will disintegrate. Note: the comet disintegrated as described in this manuscript according to reports published in CBET 3731. (3) This work raises many questions. For example: (a) what is the physical meaning of the Slope Discontinuity Event? (b) All comets in Table 1 are Oort Cloud members. What was the origin of the periodic comet P/2006 HR30 Siding Spring in Table 1 that shows the SDE? (c) Why some comets exhibit a dip of þ 0.0 magnitudes after the SDE while others show a dip of þ 1.5 magnitudes? (d) Why do these comets disintegrate at distances 1.6 to 0.63 AU? The answers to these questions require of a complex model of a comet and are beyond the scope of this paper which focuses only on the predictive power of the SDE+magnitude dip signature and path on the reduced magnitude vs log R plot. Acknowledgments We thank two unknown referees for their suggestions to improve the scientific quality of this manuscript.
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References Bobrovnikoff, N.T., 1942. Contributions from the Perkins Observatory, vol. 16. Buil, C., 2013. Comet C/2012 S1 (ISON)'s spectrum. 〈http://www.astrosurf.com/buil/ comet/ison/obs.htm〉. Combi, M. R., Bertaux, J. L., Quemerais, E., 2013. Comet C/2012 S1 (ISON). IAUC 9266. Ferrín, I., 2005. Secular light curve of comet 28P/Neujmin 1, and of comets targets of spacecraft, 1P/Halley, 9P/Tempel 1, 19P/Borrelly, 21P/Grigg-Skejellerup, 26P/ Giacobinni-Zinner, 67P/Chruyumov-Gersimenko, 81P/Wild 2. Icarus 178, 493–516. Ferrín, I., 2006. Secular light curve of comets: 133P/Elst-Pizarro. Icarus 185, 523–543. Ferrín, I., 2007. Secular light curve of comet 9P/Tempel 1. Icarus 187, 326–331. Ferrín, I., 2008. Secular light curve of comet 2P/Encke, a comet active at aphelion. Icarus 197, 169–182 〈http://arxiv.org/ftp/arxiv/papers/0806/0806.2161.pdf〉. Ferrín, I., 2009. Secular light curve of comet 103P/Hatley 2, the next target of the deep impact EPOXI mission. Planet. Space Sci. 58, 1868–1879 〈http://arxiv.org/ ftp/arxiv/papers/1008/1008.4556.pdf〉. Ferrín, I., 2010. Atlas of secular light curves of comets. Planet. Space Sci. 58, 365–391 〈http://arxiv.org/ftp/arxiv/papers/0909/0909.3498.pdf〉. Ferrín, I., 2013. Comet C/2012 S1 (ISON). http://astronomia.udea.edu.co/cometspage. Ferrín, I., 2014. The Location of Oort Cloud Comets C/2011 L4 Panstarrs and C/2012 S1 (ISON), on a Comets' Evolutionary Diagram. MNRAS, accepted for publication 〈http://arxiv.org/ftp/arxiv/papers/1306/1306.5010.pdf〉. Green, D. 2013. The Cometary Science Archive. 〈http://www.csc.eps.harvard.edu/ index.html〉. Hergenrother, C., 2010. Comet C/2009 R1 (McNaught). 〈http://transientsky.word press.com/2010/06/27/new-comet-blues-comet-mcnaught-falls-short/〉. Kamel, L., 1992. The comet light curve atlas. A&A Suppl. 92, 85–149. Meisel, D.D., Morris, C.S., 1976. Comet Brightness Parameters: Definition, Determination and Correlations. The Study of Comets, vol. I. NASA SP-393, pp. 410–444. Morris, C.S., 1994. The light curve of periodic comet Wirtanen. Int. Comet Q. 16, 178–181. Sekanina, Z., 1984. Disapearance and disintegration of comets. Icarus 58, 81–100. Sekanina, Z., 2002. What happened to comet Hönig C2002 O4? Int. Comet Q. 24, 223–236. Spahr, T., 2013. Minor Planet Center Repository of Astrometric Observations. 〈http:// www.minorplanetcenter.net/db_search〉. Vseksvyatskij, S.K., 1964. Physical Characteristics of Comets. Israel Program for Scientific Translations, Jerusalem, Israel.
Contents lists available at ScienceDirect
Planetary and Space Science journal homepage: www.elsevier.com/locate/pss
The impending demise of comet C/2012 S1 (ISON) Ignacio Ferrín Institute of Physics, Faculty of Exact and Natural Sciences, University of Antioquia, Medellin 05001000, Colombia
art ic l e i nf o
a b s t r a c t
Article history: Received 20 October 2013 Received in revised form 7 March 2014 Accepted 10 March 2014 Available online 21 March 2014
We present evidence to conclude that it is very probable that comet C/2012 S1 (ISON) will disintegrate before reaching perihelion. Figs. 1 and 7 of this work are particularly revealing. The comet is following the path of disintegrating comets and not the path of normal Oort Cloud comets, suggesting that C/2012 S1 (ISON) is going to disintegrate. Note: the comet disintegrated on November 13th, according to this prediction while this paper was being refereed (CBET 3731). & 2014 Elsevier Ltd. All rights reserved.
Keywords: Comets Comet C/2012 S1 (ISON)
1. Secular light curves of comets In a series of papers we have been developing the concept of Secular Light Curves of Comets (SLCs) (Ferrín, 2005, 2006, 2007, 2008, 2009, 2010), a scientific way to show the brightness history of a comet. In this work the SLCs are presented as the reduced magnitude vs log of the Sun's distance, R. Reduced means that the comet–Earth distance has been removed and only the dependence on the distance to the Sun remains. In this work we adopt the envelope of the dataset as the correct interpretation of the observed brightness. There are many physical effects that affect comet observations. All these effects diminish the captured photons coming from the comet, and the observer makes an error downward, toward fainter magnitudes. There are no corresponding physical effects that could increase the perceived brightness of a comet. Thus the envelope is the correct interpretation of the data. The envelope represents an ideal observer, with an ideal telescope and detector, in an ideal atmosphere. Although the above is true for the comets considered in this work, it is also recognized that some observers have a personal bias that send the magnitude above or below the envelope. Additionally in some cases the inclusion or exclusion of the tail in the measurement can change the measurement by one or more magnitudes. Fortunately this is not the case at hand, and it can be concluded that the envelope is rather sharp and a better descriptor of the whole magnitude than the mean of the data. 27 SLCs appear in the Atlas of Secular Light Curves of Comets, Version I (Ferrín, 2010). A full interpretation of the SLCs is given there and will not be repeated here. To carry out this investigation we reduced 11844 photometric observations of five comets.
E-mail address: ferrin@fisica.udea.edu.co http://dx.doi.org/10.1016/j.pss.2014.03.007 0032-0633/& 2014 Elsevier Ltd. All rights reserved.
There have been previous renditions of the light curve of a comet (see for example Bobrovnikoff, 1942; Vseksvyatskij, 1964; Meisel and Morris, 1976; Morris, 1994; Kamel, 1992). However they were not “secular light curves, SLCs” in the sense used in this work and in the Atlas. A SLC measures parameters from the plot, combines data from amateur and professionals, corrects for phase effects, does not fold the data at perihelion, uses the envelope to measure whole magnitudes, and plots the nuclear line when available. Fig. 7 and the Atlas show that the “normal” SLC of an Oort Cloud comet is basically composed of two straight lines separated by a Slope Discontinuity Event, SDE. Notice that after the SDE the normal Oort Cloud comet continue increasing in brightness up to perihelion. Disintegrating comets halt their brightness after the SDE and show a dip in magnitude. The value of the dip goes from þ0.0 for comet Hönig to þ1.5 for comet Bressi.
2. The secular light curve of comet C/2012 S1 (ISON) We are interested in creating the SLC of comet ISON to compare it with other comets. The SLCs have been corrected for phase effects. Fig. 1 shows the very odd SLC of comet C/2012 S1 (ISON) using CCD-R magnitudes available in the internet (Green, 2013; Spahr, 2013). Three things are apparent in Fig. 1. First, there is a SDE very clearly defined at a distance of around 4.1 AU pre-perihelion. Second, there is a slight deep in the light curve just after the event with a U-shape. And third, farther in at 2.8 AU the light curve starts to grow again. This “signature” (SDE þdip) was verified in four additional datasets. The dataset from the Minor Planet Center Database of Astrometric observations is presented in Fig. 2. To reduce the
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Fig. 1. The very odd SLC of comet C/2012 S1 (ISON). It exhibits a SDE at about 4.1 AU from the Sun, followed by a dip and an increase in brightness. This behavior is entirely different to the behavior of a normal Oort Cloud comet, shown in Fig. 7, composed of two straight lines of different slope. Data phase corrected. In this and the following plots, negative logs do not mean numbers less than one. Negative logs mean observations before perihelion so all log numbers are positive. From this plot a magnitude of the dip, mR(POST-SDE) mR(PRE-SDE) ¼ þ0.4, can be measured.
Fig. 2. The dataset from the Minor Planet Center Database, contains photometry from astrometric observations. To reduce the vertical dispersion, daily mean values have been calculated. The plot shows the same SDE þ magnitude dip signature than the CCD dataset. Since these are independent datasets, the signature must be real. From this plot a magnitude of the dip, mR(POST-SDE) mR(PRE-SDE) ¼ þ 0.4, can be measured.
vertical dispersion daily means have been calculated. Since these two datasets are independent, this signature must be a real phenomenon. It must be mentioned that the Minor Planet Center database does not specify the filter of the observations. Actually the database is a mixture of CCD-V, CCD-R, CCD-I, sloan r', sloan g', and luminance/unfiltered observations. Accordingly, this database
is not used for any scientific calculation other than detecting and showing the location of the Slope Discontinuity Event. A search for the signature was conducted in a database of 87 comets that are being prepared for the Atlas, Version II. Two instances were found with similar behavior. The first one is comet C/2002 O4 (Hönig). The light curve is shown in Fig. 3. It shows a behavior reminiscent of comet C/2012 S1 (ISON). We see a clear
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Fig. 3. The SLC of comet C/2002 O4 Hönig. This comet exhibits the same SDE signature and the flattening of the light curve. Data for this plot extracted from Sekanina (2002). From this plot a magnitude of the dip, mR(POST-SDE) mR(PRE-SDE) ¼ þ 0.0, can be measured.
Fig. 4. The SLC of comet C/1996 Q1 Tabur. The data set for this plot comes from the ICQ database maintained by Daniel Green (2013). It exhibits the same signature, a SDE þdip, then a maximum and then a disintegration. From this plot a magnitude of the dip, mR(POST-SDE) mR(PRE-SDE) ¼ þ0.17, can be measured.
slope discontinuity event, a flattening of the light curve, an increase, and then the comet disintegrates. A second case was found in the database, that of comet C/1996 Q1 (Tabur). The SLC of this comet can be seen in Fig. 4. Once again we find the same behavior and signature. A well-defined SDE, a dip after the event, a leveling off and then a precipitous decay into disintegration. After this report appeared in the Arxiv.org data repository, Gary Kronk, Anthony Cook and Jacub Cerny have identified four new
members. They are comets C/1999 S4 (LINEAR), C/2010 X1 (Elenin), C/2012 T5 (Bressi), and C/1997 N1 (Tabur) (unconfirmed) (see Table 1). The first three exhibited the same signature and disintegrated. The SLCs of comet LINEAR appears in Fig. 5 and that of comet Bressi is shown in Fig. 6. While this paper was being refereed, two new members have been identified. They are C/2009 R1 (McNaught) (Hergenrother, 2010) and C/2012 K1 (Panstarrs). A paper by Sekanina (1984) contains sparse information on 7 additional comets, so the total
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Table 1 ISON's group (7)(8)(9). #
Comet
01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20
C/2002 C/2012 C/1999 C/2013 C/2009 C/2012 C/2012 C/2012 C/2010 C/1996 C/1897 C/1957 C/1974 C/1953 C/2008 C/1925 C/1887 20D/1913 P/2006 C/1997
O4 T5 S4 V5 R1 V1 S1 K1 X1 Q1 U1 U1 V2 X1 J4 X1 B1 S1 HR30 N1
(Hönig) (Bressi) (LINEAR) (Oukaimeden) (McNaught) (Panstarrs) (ISON) (Panstarrs) (Elenin) (Tabur) (Perrine) ¼ 1897 III (Latyshev-Wild-Burnham) (Bennet) 1974XV (Pajdusakova) 1954 II (McNaught) Headless comet (Ensor) ¼1926 III headless comet (Westphal) (Siding Spring) (Tabur) (unconfirmed)
R (DISIN) [AU]
q [AU]
CODE (0)
1/a ORIGINAL or e (10)
Identifier (1)
(5) 0.88 0.66 0.92 (6) – (4) 0.79 – (11) 0.67 (6) – 0.64 0.93 1.61 1.11 0.98 0.74 0.64 0.63 (2) – 1.43 (3) – –
0.78 0.32 0.77 0.63 0.41 2.09 0.01 1.05 0.48 0.84 1.36 0.54 0.86 0.07 0.45 0.32 0.005 1.25 1.23 0.40
Sþdþ DN þD Sþdþ DN þD Sþdþ DN þD Sþdþ DN Sþdþ DN þD Sþdþ DN þD Sþdþ DN þD Sþd Sþdþ D Sþdþ D D D D D D D D D Sþd D
0.00077249 0.00022724 0.00005451 0.00003227 0.00003180 0.00001928 0.00000852 0.00001807 0.00011071 0.00182608 1.0000000 1.0000000 1.0000000 1.000000 1.000000 1.000000 1.0000000 0.9198301 0.8437940 1.0001344
I. Ferrín J. Cerny G. Kronk I. Ferrín C. Hergenrother I. Ferrín I. Ferrín I. Ferrín A. Cook I. Ferrín Z. Sekanina Z. Sekanina Z. Sekanina Z. Sekanina I. Ferrín Z. Sekanina Z. Sekanina Z. Sekanina I. Ferrín G. Kronk
0. CODE: S ¼Slope Discontinuity Event (SDE); d ¼ dip after SDE; DN¼ Dynamically New; D¼ Disintegrated. Additionally the group has 1.61o R(DIS) o 0.63 AU. 1. After publishing the first manuscript in the Arxiv.org depository, Gary Kronk, Toni Cook and Jacub Cerny (personal communication), discovered four additional members of the group. 2. See Sekanina (1984). 3. All comets in this list are Oort Cloud members, while this comet is periodic, which raises some interesting questions about its origin. Additionally this comet has not disintegrated and it is due to return in 2027. However it exhibits the signature. 4. Hergenrother (2010)has a light curve showing the SDE þdip, while Siichi's web site http://www.aerith.net shows that the comet was not detected post-perihelion, all consistent with disintegration, although this was not observed. 5. Dynamically new comets have been highlighted in black. 6. These two comets exhibit the SDEþ dip signature, but are still far from perihelion and have not yet disintegrated. 7. From Column 3, R(Disintegration), we deduce that there is a R(limit) ¼ 0.63 AU (Pre-perihelion). All comets have disintegrated before reaching this limit. 8. From the next to the last column, it is clear that dinamically new comets have a clear tendency to disintegrate. 9. The SLCs of many of these comets have been presented by Ferrín (2013, 2014) and are not repeated here due to space limitations. 10. In this work we define dynamically new as 1/a(original)o 0.00001000. The 1/a(original) value is given when available. 11. The disintegration distance for comet ISON was determined using data by Ferrín (2013a) and by Combi et al. (2013) (CBET 9266).
Fig. 5. The SLC of comet C/1999S4 LINEAR, exhibits the same signature characteristic of disintegrating comets. This comet was identified by Gary Kronk. The data set for this plot comes from the ICQ database maintained by Daniel Green (2013). From this plot a magnitude of the dip, mR(POST-SDE) mR(PRE-SDE) ¼ þ 0.5, can be measured.
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Fig. 6. The secular light curve of comet C/2012 T5 Bressi shows the same signature as other disintegrating comets. This comet was identified by Jacub Cerny after posting the original paper in the Arxiv.org depository. The data comes from the Minor Planet Center database. From this plot a magnitude of the dip, mR(POST-SDE) mR(PRE-SDE) ¼ þ 1.5, can be measured.
Fig. 7. A comparison is made of Normal Oort Cloud comets with disintegrating comets. Normal Oort Cloud comets show two linear laws separated by a SDE. After the event they continue increasing in brightness up to perihelion. Disintegrating comets stop their brightness increase after the SDE. Shortly after they disintegrate. In view of the fact that comet C/2012 S1 (ISON) is following the path of disintegrating comets and not the path of normal Oort Cloud comets, it is very probable that the comet will disintegrate. The plot shows the envelopes of the comets. Note: While this paper was being refereed the comet disintegrated (CBET 3731).
confirmed members is now 17 (see Table 1). This table gives the distances at which disintegration took place. Finally Fig. 7 shows all the SLCs of these comets plotted together along the SLCs of normal Oort Cloud comets. Normal Oort Cloud comets have SLCs composed of two straight lines separated by the SDE, after which they continue brightening up to perihelion. Disintegrating comets halt their light after the SDE. The fact that we had to correct the SLCs for phase effects implies that the coma is dominated by large particles and that there are
significant quantities of dust. A spectrum of comet C/2012 S1 (ISON) taken by Buil (2013) confirms that there were almost no gas lines, and that the comet was dominated by large particles on that particular date or period around that date (2013, October 11). A bare nucleus like an asteroid has a brightness law behaving as R∧( 2.0). Any slope less than this value implies that the comet is fading. The fact that the comets in Figs. 1–6 exhibit a dip in magnitude after the SDE that goes from þ0.0 for comet Hönig to þ1.5 for comet Bressi, implies that all these comets are fading after
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the SDE. The reason for this fading cannot be addressed in this work, and requires a complex cometary model beyond the scope of this paper. 3. Conclusions (1) Comets of the Oort Cloud announce that they are going to disintegrate by exhibiting the SDE+magnitude dip signature. Of the 13 comets with this signature in Table 1, 13 disintegrated. (2) Additionally, the fact that it is following the path of disintegrating comets and not the path of normal Oort Cloud comets, implies that it is very probable that the comet will disintegrate. Note: the comet disintegrated as described in this manuscript according to reports published in CBET 3731. (3) This work raises many questions. For example: (a) what is the physical meaning of the Slope Discontinuity Event? (b) All comets in Table 1 are Oort Cloud members. What was the origin of the periodic comet P/2006 HR30 Siding Spring in Table 1 that shows the SDE? (c) Why some comets exhibit a dip of þ 0.0 magnitudes after the SDE while others show a dip of þ 1.5 magnitudes? (d) Why do these comets disintegrate at distances 1.6 to 0.63 AU? The answers to these questions require of a complex model of a comet and are beyond the scope of this paper which focuses only on the predictive power of the SDE+magnitude dip signature and path on the reduced magnitude vs log R plot. Acknowledgments We thank two unknown referees for their suggestions to improve the scientific quality of this manuscript.
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