Solar Physics

, Volume 281, Issue 1, pp 167–185

Three-Dimensional Properties of Coronal Mass Ejections from STEREO/SECCHI Observations

Authors

    • Institute for AstrophysicsUniversity of Göttingen
  • V. Bothmer
    • Institute for AstrophysicsUniversity of Göttingen
  • G. Nisticò
    • Dipartimento di FisicaUniversita della Calabria
  • A. Vourlidas
    • Spaces Sciences DivisionNaval Research Laboratory
  • R. A. Howard
    • Spaces Sciences DivisionNaval Research Laboratory
  • J. A. Davies
    • Rutherford Appleton Laboratory

DOI: 10.1007/s11207-012-0123-5

Abstract

We identify 565 coronal mass ejections (CMEs) between January 2007 and December 2010 in observations from the twin STEREO/SECCHI/COR2 coronagraphs aboard the STEREO mission. Our list is in full agreement with the corresponding SOHO/LASCO CME Catalog ( http://cdaw.gsfc.nasa.gov/CME_list/ ) for events with angular widths of 45 and up. The monthly event rates behave similarly to sunspot rates showing a three- to fourfold rise between September 2009 and March 2010. We select 51 events with well-defined white-light structure and model them as three-dimensional (3D) flux ropes using a forward-modeling technique developed by Thernisien, Howard and Vourlidas (Astrophys. J. 652, 763 – 773, 2006). We derive their 3D properties and identify their source regions. We find that the majority of the CME flux ropes (82 %) lie within 30 of the solar equator. Also, 82 % of the events are displaced from their source region, to a lower latitude, by 25 or less. These findings provide strong support for the deflection of CMEs towards the solar equator reported in earlier observations, e.g. by Cremades and Bothmer (Astron. Astrophys. 422, 307 – 322, 2004).

Keywords

Coronal mass ejection

1 Introduction

Since the start of science operations in January 2007, the imagers and coronagraphs of the Sun-Earth Connection Coronal and Heliospheric Investigation (SECCHI) suite (Howard et al. 2008), aboard the twin STEREO spacecraft (Kaiser et al. 2008), have provided simultaneous observations of coronal mass ejections (CMEs) from different vantage points in space. Using the white-light synoptic movies provided by the two STEREO/SECCHI/COR2-A and -B coronagraphs, we have compiled a list of 565 coronal mass ejections (CMEs) between January 2007 and December 2010. The CMEs were observed under increasing spacecraft separation angles ranging from about 0 in the early mission phase up to 175 in December 2010. The CME list contains basic information, such as Carrington Coordinates of both spacecraft, CME detection times and position angles, etc. and is available online at the website http://soteria-event.uni-graz.at/ .1 The list was compiled as part of the EU FP7 project SOTERIA (SOlar TERrestrial Investigations and Archives).

A comparison of the monthly average CME rate from the SOTERIA COR2 CME list with the CME rate derived from the SOHO/LASCO CME Catalog2 yields a very good correspondence for CME events with angular widths greater than or equal to 45. Thus, the SOTERIA COR2 CME list consists of classic large-scale CMEs, such as analyzed, e.g., by Cremades and Bothmer (2004). Figure 1 shows the comparison of the monthly CME rates from SECCHI and LASCO between January 2007 and December 2010, together with the monthly smoothed sunspot number (SSN) provided by the Solar Influences Data Analysis Center (SIDC)3 of the Royal Observatory of Belgium. Figure 1 shows that the monthly CME rates and monthly smoothed sunspot numbers show generally similar trends but not detailed correlations as has been reported in earlier studies (e.g., St. Cyr et al. 2000). We note that both the CME and sunspot monthly rates rise by a factor of three to four between September 2009 and March 2010 and remain high in the following months. This increase can be interpreted as the start of the rise of solar activity towards the next solar maximum expected around 2012 – 2013. It is interesting to note that the CME rate remains constant (at 10/month for SECCHI and 7/month for LASCO) for several months in 2009 although the corresponding sunspot number hovers around zero. We investigate the low-coronal source regions of these CMEs using the SECCHI Extreme Ultraviolet Imager (EUVI) at 195 and 304 Å. We find that they relate to bipolar photospheric regions of lower magnetic flux and quiescent prominence eruptions, in agreement with the results obtained for the CME source regions studied by Cremades and Bothmer (2004). However, for a number of CMEs, no source region could be identified as in the case of the “stealth CME” reported by Robbrecht, Patsourakos, and Vourlidas (2009). The differences between the CME rates and sunspot numbers after January 2010 can be explained in terms of decaying active regions of less intense magnetic flux remaining unidentified as sunspots but remaining a source of CME origin, again in agreement with what has been proposed by Tripathi, Bothmer, and Cremades (2004).
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Figure 1

Monthly CME rates observed by STEREO/SECCHI/COR2 (solid line) and those derived from the SOHO/LASCO/C2 CME catalog (dashed line) with an angular width ≥45 for the time period January 2007 until December 2010. The monthly sunspot number (dotted line) is provided by the SIDC at the Royal Observatory of Belgium. (Solar Influences Data Analysis Center, Royal Observatory of Belgium: 2010, Monthly and monthly smoothed sunspot number, http://sidc.oma.be/sunspot-data/ .)

From the SOTERIA COR2 list of 565 events, we constructed a “Best-of” list of 120 events based on their clear morphology (judged visually) in the COR2 images. So far, we have fitted 51 of these events as flux ropes with a forward-modeling technique developed by Thernisien, Howard, and Vourlidas (2006) and Thernisien, Vourlidas, and Howard (2009). The flux rope structure is represented by a geometrical construction, called the Graduated Cylindrical Shell (GCS) and is based on the idea that the flux rope morphology can account for the CME white-light observation (Chen et al. 1997; Vourlidas et al. 2000; Cremades and Bothmer 2004).

In the following sections we give a brief introduction to the GCS Model and a brief presentation of the modeling results and comparisons with the CME source region characteristics.

2 The GCS Model

For the investigation of the three-dimensional (3D) structure of the “STEREO/SECCHI/COR2 Best-of CMEs”4 the Graduated Cylindrical Shell forward-modeling technique developed by Thernisien, Howard, and Vourlidas (2006) was applied. The geometry and electron density distribution of the GCS flux rope geometry is shown in Figure 2. The GCS geometry consists of two funnel-shaped legs each of length h. The segment h, along the axis through the center of the shell (dash-dotted line), is defined by the center of the Sun, labeled “O”, and by the upper end of the cone. The angle between both axes is 2α or α for the half angle, one of the six parameters which define the geometry of the model. The upper part of the model, connecting both legs, is tube shaped. The right image in Figure 2 shows an edge-on view of the model consisting of a circle with the varying radius a for the cross section of the tubelike part and below the tube section the mentioned cone of the legs. As opposed to the length h of the legs \(h_{\rm front}\) describes the distance or height between the center of the Sun “O” and the leading edge of the CME. \(h_{\rm front}\) can be determined using the parameters h,a,r and α, which are shown in Figure 2.
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Figure 2

The Graduated Cylindrical Shell Model with a face-on view on the left and an edge-on view on the right. The assumed electron density distribution is shown in the upper right and described with a Gaussian-like function (Thernisien, Howard, and Vourlidas 2006).

In order to describe the position and orientation of the flux rope in 3D space the parameters ϕ,θ and γ define the Carrington longitude and heliographic latitude of the apex projection on the solar surface and the tilt angle γ of the source region (SR) neutral line (Figure 3). In this figure the GCS model is oriented normal to the solar surface and located with the projection of the apex on the solar surface at the given (ϕ,θ)-Coordinates where the center of the neutral line of the SR can be found. The legs of the model are located at the opposite ends of the neutral line (NL), which has a tilt angle γ relative to the solar equator. Table 1 provides an overview of the GCS model parameters. Further information regarding the GCS Model can be found in Thernisien, Howard, and Vourlidas (2006) and Thernisien, Vourlidas, and Howard (2009).
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Figure 3

Position and orientation of the GCS Model in 3D Space with the parameters ϕ,θ and γ for the Carrington longitude and heliographic latitude of the apex and the tilt angle, respectively (Thernisien, Vourlidas, and Howard 2009).

Table 1

Parameters of the GCS Model and the electron density distribution, adapted from Thernisien, Howard, and Vourlidas (2006).

Parameter

[units]

Description

2α

[deg]

Angle between the axis of both legs

h

[\(r_{\rm sun}\)]

Height of the legs

\(h_{\rm front}\)

[\(r_{\rm sun}\)]

Distance from center of the Sun to leading edge

κ

 

Aspect ratio of a and r

ϕ

[deg]

Carrington longitude of the projection of apex on the Sun’s surface

θ

[deg]

Heliographic latitude of the projection of apex on the Sun’s surface

γ

[deg]

Tilt angle of the SR neutral line relative to the solar equator

a

 

Cross section radius of the tube section

r

 

Distance from center of the Sun to the outer boundary of the shell

3 Examples of GCS Modeling of Events from the “Best-of” List

3.1 CME of 4 August 2009

We apply the GCS model to the CME detected on 4 August 2009 (Figure 4) when the two STEREO spacecraft were separated by 107.5 in heliographic longitude, i.e. they observed the CME from different viewing angles. The two STEREO spacecraft detected the CME at different position angles (PA) of 90 and 270, respectively, as shown in the COR2-A and COR2-B (left) images in Figure 4. The GCS modeling technique was applied to base-difference COR2 images after they had been processed using the standard routines (secchi_prep).5 For the fit, we selected the time when the CME was the brightest in the COR2 field of view. On 4 August 2009, the CME was modeled when it was observed at 23:22 UT when its leading edge had reached a distance of about 13 solar radii. The right panels in Figure 4 show the modeling results through overlays of the GCS wireframe flux rope geometry on the CME images. The six parameters which describe the geometry of the GCS model are summarized in Table 2.
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Figure 4

Left column of images: STEREO/SECCHI/COR2-A (top row) and -B (bottom row) white-light coronagraph observations of the CME detected on 4 August 2009 at 23:22 UT. The separation angle between the two spacecraft was 107 in longitude. Right column of images: wireframe rendering results (overlaid in green) derived through the GCS Model.

Table 2

Model results through GCS forward-modeling of two CMEs observed on 4 August 2009 and 1 February 2010.

Parameter

CME 1 (4 August 2009)

CME 2 (1 February 2010)

Longitude

ϕ [deg]

222.5

39.1

Latitude

θ [deg]

−2.8

−18.4

Tilt angle

γ [deg]

0.0

15.1

Height

\(h_{\rm f}\) [\(r_{\rm s}\)]

13.4

16.8

Aspect ratio

κ

0.3

0.3

Half angle

α [deg]

12.0

23.2

The synthetic coronagraphic images generated with a ray-tracing code are shown in Figure 5. The ray-tracing code allows us to render the 3D electron density distribution into a coronagraph image taking into account Thomson scattering. In this case, the CME detected in the COR2 field of view is represented by a flux rope which has its apex located at 222 in Carrington longitude lying in the solar equatorial plane (see Table 2). The radial height of its leading edge is 13 solar radii. Figure 5 further shows the modeled flux rope footpoints and apex locations projected onto the EUVI 195 Å images (right column) for the time of the COR2 modeling. Green crosses signify that the flux rope is located on the visible side of the solar disk whereas white crosses define a backsided flux rope. The white-light structure of the 4 August 2009 CME reveals features similar to many other cases of the “COR2 Best-of CME” list.
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Figure 5

Left column: GCS synthetic coronagraph images for the CME observed on 4 August 2009 at 23:22 UT as shown in Figure 4. The separation angle between the two spacecraft was 107 in longitude. Right column: STEREO/SECCHI/EUVI-A (top) and -B (bottom) observations at 195 Å with projection of the flux rope footpoints and apex on the Sun’s surface.

3.2 CME of 1 February 2010

As discussed earlier solar activity as represented by the sunspot number and the monthly rate of CMEs has shown increased levels since about February 2010. In contrast to a CME typical of the solar minimum years, Figure 6 shows a CME detected on 1 February 2010, i.e. in the early rising phase of Cycle 24. At this time STEREO-A and -B were separated by 135.3 in heliographic longitude and observed the CME at PAs of about 180 and 225, respectively. The GCS modeling results are summarized in Table 2. The flux rope parameters fitting this CME differ from those of the 4 August 2009 event. In this case, the flux rope apex was located 18 south of the solar equator and exhibited a tilt angle of 15. The angular width was 46, i.e. its calculated half angle of 23 was double the size of the August event. During this time period CMEs generally started looking wider and more massive in white-light coronagraph images. Because of the large angular separation of the COR2-A and -B instruments, the CME looks different in the COR2-A and -B images. The GCS synthetic coronagraphic images generated with the ray-tracing code for this event are shown in Figure 7 together with EUVI-A and -B observations taken at 195 Å.
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Figure 6

Left column of images: STEREO/SECCHI/COR2-A (top) and -B (bottom) white-light coronagraph observations of the CME detected on 1 February 2010 at 21:08 UT. The separation angle between the two spacecraft was 135 in longitude. Right column of images: wireframe rendering results (overlaid in green) derived through the GCS Model.

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Figure 7

Left column: GCS synthetic coronagraph images for the CME observed on 1 February 2010 at 21:08 UT as shown in Figure 6. The separation angle between the two spacecraft was 135 in longitude. Right column: STEREO/SECCHI/EUVI-A (top) and -B (bottom) observations at 195 Å with projection of the flux rope footpoints and apex on the Sun’s surface.

3.3 GCS Modeling Results for “COR 2 Best-of CMEs”

Out of the 120 events of the “STEREO/SECCHI/COR2 Best-of List”6 51 events have been modeled similarly to the sample events described in Sections 3.1 and 3.2. The modeled events hitherto were from 2010 because they appeared brighter and were easier to model than the fainter cases appearing at solar minimum. Figure 8 shows the calculated latitudes for 51 flux rope apexes resulting from the modeling of the CMEs in 2010. In 2010 the flux rope apexes were located between 30 southern and 40 northern latitude. Figure 9 shows the calculated GCS flux rope tilt angles plotted versus time in 2010. The tilt angle of a modeled flux rope denotes the angle between the line between its footpoints and apex which are projected on the solar surface and the solar equator. The flux rope is oriented parallel to the equator for an angle of 0 and perpendicular for 90. The CMEs observed north and south of the solar equator show a similar pattern of scatter in the range of up to 30 – 40. It is interesting to note that apart from one exception, flux ropes with a tilt angle larger than roughly 40 are lacking. In this context it is important for further studies to inspect the tilt angle of the remaining “Best-of CMEs” observed between 2007 and 2009, because Thernisien, Vourlidas, and Howard (2009) found that e.g. the CMEs on 31 December 2007 and 23 January 2008 exhibit a large tilt angle of 90 and −49, respectively. A further investigation of this aspect is needed to understand better the inclination characteristics of flux rope CMEs. Figure 10 shows the distribution of the GCS flux rope half angles α which represents through 2α the separation angle between both legs of the flux rope. The typical half angle of the flux ropes is estimated to lie between 10 and 25 during 2010 for a CME observed between 10 and 15 solar radii. A half angle of 10 to 25 corresponds to an angular width of the CME lying between 20 and 50 which is comparable to the typical angular width of CMEs observed by SOHO/LASCO (e.g. St. Cyr et al. 2000; Yashiro et al. 2004).
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Figure 8

Distribution of latitude of the calculated apex position projected on the solar surface for 51 GCS-modeled CMEs observed in 2010.

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Figure 9

Tilt angle distribution of the line of modeled footpoints and apex projected on the solar surface for 51 GCS-modeled CMEs observed in 2010.

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Figure 10

Distribution of the calculated flux rope half angle for 51 GCS-modeled “Best-of CMEs” observed in 2010.

It should be noted that since the fits are done by hand they exhibit the modeler’s subjective understanding of the observed CME. Hence the fit results depend to a certain extent on the experience of the user for the interpretation of the CME white-light observation. In this context Thernisien, Vourlidas, and Howard (2009) used a merit function to determine how well the model is able to reproduce an observed CME’s white-light structure. After performing a sensitivity analysis of the model parameters, the authors found that the deviations in the parameters γ and α are an order of magnitude larger than the deviations in the longitude and latitude. Hence the values for the tilt angle may exhibit a larger uncertainty than the one of the other parameters.

4 Comparison with source region and discussion

To compare the calculated GCS parameters (Table 4) of the flux ropes with the CME associated source region characteristics, we investigated the source region for each CME using SECCHI and SOHO/MDI data. For each modeled CME event we used the SECCHI/COR1 observations to track the CME back towards the low corona and then used the EUVI 195 Å and 304 Å observations to identify the coronal SR.

After identification of a CME’s source region we compared the calculated apex position provided by the GCS modeling to the SR location. Figure 11 shows a histogram of the differences between the SR longitude and the modeled apex position in bins of 15 Carrington longitude for 39 events. For the 12 remaining CMEs no associated SRs could be determined. We find that for 82 % (32 out of 39) of the CME events the discrepancy is not larger than 30. Larger deviations occur only for a small number of events (7 out of 39) and the larger differences are decreasingly frequent. A similar behavior is found for the difference in solar latitude between identified SR and modeled apex position as shown in Figure 12. Here 82 % (32 out of 39) of all CME events exhibit a discrepancy of less than 25 in solar latitude. Considering a 10 difference as insignificant, we can conclude that 41 % of all CMEs do not deflect latitudinally while the rest of the same exhibits a very modest 23 average deflection to lower latitudes.
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Figure 11

Differences in Carrington Longitude between observed SR and GCS-modeled apex position in bins of 15 for 39 CME events and their associated source regions. For the 12 remaining CMEs no associated SRs could be determined.

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Figure 12

Differences in latitude between observed SR and GCS-modeled apex position in bins of 10 for 39 CME events and their associated source regions. For the 12 remaining CMEs no associated SRs could be determined.

Next we projected the calculated apexes onto SOHO/MDI (Michelson Doppler Imager) Synoptic Charts7 shown for the CME event observed on 4 June 2010. The center of the observed SR is labeled with a white plus sign and is located within a magnetic bipolar region. For a better visibility the SR is surrounded by a white circle. The radius of the circle is arbitrary with no reference to the spatial extent of the SR. In this case we assume a prominence as the SR, indicated with “P”. The position of the apex is marked with a green asterisk and the footpoints with green squares connected with a line which simultaneously denotes the orientation of the flux rope axis. The length of the footpoint line corresponds to the half angle α, respectively, 2α, the angle between both legs of the flux rope. In this case the apex projection lies only 13 south of the identified CME SR with an offset of only 16 in solar longitude. The MDI map reveals a bipolar photospheric region as a source of the analyzed CME as found in the studies of Tripathi, Bothmer, and Cremades (2004). In this case also the tilt of the neutral line of the regions of opposite magnetic polarity and the modeled tilt of the flux rope CME, both being of the order 30, do agree very well.

In contrast to Figure 13, Figure 14 presents an example of a larger discrepancy between the SR latitude and CME latitude for a CME observed on 8 March 2010. In this case the deviation amounts to 37 in solar latitude.
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Figure 13

SOHO/MDI Synoptic Chart for Carrington Rotation 2097 labeled with the center of observed SR (white encircled plus sign) and the position of apex and footpoints of the GCS modeled CME observed on 4 June 2010 (green).

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Figure 14

SOHO/MDI Synoptic Chart for Carrington Rotation 2094 labeled with the center of observed SR (white) and the position of apex and footpoints of the GCS modeled CME observed on 8 March 2010 (green).

5 Conclusion

In this paper we introduce a CME list8 based on STEREO/SECCHI/COR2 coronagraph observations. We found that the COR2 CME list is in good agreement with the LASCO CME catalog for events with an angular width greater than or equal to 45. The COR2 CME list (available online at http://soteria-event.uni-graz.at/ ) of the EU Seventh Framework Programme project SOTERIA can be considered as a valuable resource of classical large-scale CMEs. We find the monthly CME rates derived by LASCO and SECCHI observations rise by a factor of 3 to 4 between September 2009 and March 2010. This increase can be interpreted as the start of the overall rise of solar activity towards the next solar maximum expected around the year 2012 – 2013.

From the SOTERIA COR2 CME list we selected 120 events as a “Best-of” list based on their brightness appearance in the COR2 field of view. Fifty-one of the “Best-of CMEs” have been modeled using the GCS forward-modeling technique developed by Thernisien, Howard, and Vourlidas (2006) and Thernisien, Vourlidas, and Howard (2009) to infer the CME’s 3D structure. The modeling results reveal:
  • A good fit of the observed CME white-light structure as GCS flux ropes.

  • The calculated GCS apex latitude position is between 30 southern and 40 northern hemisphere of the solar equator for CMEs observed in 2010.

  • The tilt angle for GCS modeled flux ropes is distributed between roughly ±40.

  • The flux rope half angle extends from 10 up to 25 which corresponds to an angular width of the CME lying between 20 and 50.

From the comparison of the GCS modeled apex position with the identified associated source region position it is found that in 82 % of the CME events the discrepancy extends from 0 up to 30 in Carrington longitude. Larger deviations occurred only for a smaller number of events and the larger differences are also less frequent. A similar behavior is found for the difference in solar latitude between the identified SR and modeled apex positions. Here 82 % of all CME events exhibit a discrepancy of less than 25 in solar latitude. These findings imply that the observed CMEs were commonly deflected away from the radial direction over the first few solar radii.

Some issues which were not discussed in detail in this study but are important and very interesting pertain to error bars of the GCS model parameters. So for example, it should be considered that the deviation for the parameters γ and α are an order of magnitude larger than the deviation for the longitude and latitude. Hence the values for the tilt angle exhibit a larger uncertainty than those for the other parameters (Thernisien, Vourlidas, and Howard 2009). Further analysis of the calculated GCS flux rope parameters and the investigation of possible CME deflection and CME distortion will be undertaken in the near future.

Footnotes
1

Also available in Tables 1 and 2 in the Electronic Supplementary Material.

 
2

CDAW Data Center, Solar Physics Laboratory (Code 671) Heliophysics Science Division, NASA / Goddard Space Flight Center, Greenbelt Maryland, USA: 1996 – 2011, SOHO/LASCO CME Catalog, http://cdaw.gsfc.nasa.gov/CME_list/ .

 
3

Solar Influences Data Analysis Center, Royal Observatory of Belgium: 2010, Monthly and monthly smoothed sunspot number, http://sidc.oma.be/sunspot-data/ .

 
4

The complete “Best-of” CME list is shown in Table 3 in the Appendix and in Table 3 in the Electronic Supplementary Material.

 
5

Colaninno, R.: 2006 – 2010, The SECCHI_PREP Homepage, Naval Research Laboratory (NRL/GMU), http://secchi.nrl.navy.mil/wiki/pmwiki.php?n=Main.HomePage .

 
6

The complete “Best-of” CME list is shown in Table 3 in the Appendix and in Table 3 in the Electronic Supplementary Material.

 
7

Stanford-Lockheed Institute for Space Research, W.W. Hansen Experimental Physics Laboratory (HEPL), Stanford University: 2010, MDI Magnetic Field and Intensity Synoptic Charts, http://soi.stanford.edu/magnetic/index6.html .

 
8

Available in Tables 1 and 2 in the Electronic Supplementary Material.

 

Acknowledgements

The research leading to these results has received funding from the European Community’s Seventh Framework Programme (FP7/2007 – 2013) under the grant agreement n° 218816 (SOTERIA project, www.soteria.eu ). Volker Bothmer acknowledges support of the project Stereo/Corona by the German Bundesministerium für Bildung und Forschung through the deutsche Zentrum für Luft-und Raumfahrt e.V. (DLR, German Space 59 Agency) as a collaborative effort with the Max-Planck-Institut für Sonnensystemforschung (MPS) under grant 50 °C 0904. Stereo/Corona is a science and hardware contribution to the optical image package SECCHI, developed for the NASA STEREO mission. The STEREO/SECCHI data used for this study are prepared by an international consortium of NASA Goddard Space Flight Center (USA), Lockheed Martin Solar and Astrophysics Lab (USA), Naval Research Laboratory (USA), Rutherford Appleton Laboratory (UK), University of Birmingham (UK), Max-Planck-Institut für Sonnensystemforschung (Germany), Institut d’Optique Thèorique et Appliquèe (France), Institut d’Astrophysique Spatiale (France) and Centre Spatiale de Liège (Belgium). The NRL effort was supported by NASA, the USAF Space Test Program and the Office of Naval Research. The work of Angelos Vourlidas and Russell A. Howard is supported by NASA contract S-136361-Y to the Naval Research Laboratory. Data from the SOHO/MDI instrument are courtesy of the SOHO/MDI consortium. The SOHO/MDI data are produced by an international consortium of the Naval Research Laboratory (USA), Max-Planck-Institut für Aeronomie (Germany), Laboratoire d’Astronomie (France) and the University of Birmingham (UK). SOHO is an international project of collaboration between ESA and NASA.

Open Access

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Supplementary material

11207_2012_123_MOESM1_ESM.pdf (184 kb)
(PDF 184 kB)

Appendix

“Best-of CME” List:
Table 3

“Best-of CME” list with 120 CMEs detected with STEREO/SECCHI/COR2- A/B for the time period from January 2007 until December 2010. No indicates the CME-Number in the COR2 list, modeled CMEs are marked with m. Date and time (n stands for next day) corresponds to the observation time with COR2-A and -B, respectively. PA denotes the position angle corresponding to the COR2 field of view with 0 pointing to the solar north and increasing angle counter-clockwise. A and B in the last column indicate how good the CME was visible in COR2-A and -B observations for the user (−− very faint, − faint, + good and ++ very good). H stands for Halo and pH for partial Halo CME.

No

Date yyyymmdd

Time(A) hh:mm:ss

PA(A) [deg]

Time (B) hh:mm:ss

PA(B) [deg]

Comments

005

20070124

15:02:40

90

15:02:46

90

A++, B−

007

20070130

11:02:40

270

12:02:48

270

A+, B−

020

20070312

00:02:40

90

00:03:01

90

B−, A+

025

20070331

09:52:30

270

09:52:58

270

B+

035

20070509

04:22:30

90

04:53:14

90

A+, B−

038

20070515

19:22:30

45

20:23:17

45

A++, B−

049

20070604

21:22:30

270

03:23:24n

270

A+, B−

050

20070607

20:22:30

225

21:23:25

225

A+, B−

060

20070708

20:22:30

90

21:23:32

90

A+, B−

071

20070821

08:52:30

270

10:53:33

270

A+, B−

078

20071008

17:22:30

270

16:53:22

270

A−, B−

083

20071104

13:52:20

45

20:23:02

45

A+, B−−

086

20071116

10:52:20

225

12:52:57

225

A+, B−−

092

20071231

01:22:20

135

01:52:42

135

A++, B+

093

20080102

10:22:20

90

11:22:41

90

A++, B+

095

20080122

23:52:20

180

23:52:38

135

A+, B+

096

20080129

00:22:20

270

00:22:37

270

A+, B−

100

20080212

07:52:20

225

09:22:36

225

A+, B−

104

20080223

20:52:20

45

17:52:37

45

A+, B−

105

20080227

12:52:20

270

10:22:37

270

A+, B−

107

20080317

15:52:20

270

12:52:40

270

B−, A−−

111

20080325

19:22:20

90

19:52:42

90

A+, B−

113

20080405

16:22:20

270

16:52:45

270

A+, B−

121

20080426

14:52:20

45

15:52:53

315

A+, B−−

125

20080517

10:52:20

90

12:23:01

90

A+, B−−

130

20080601

23:22:20

90

A+

141

20080731

06:22:20

270

A−

145

20080908

02:22:20

270

03:53:22

90

A−−, B+

156

20081017

09:52:20

270

10:53:14

90

A−, B+

158

20081026

23:52:20

270

22:23:11

270

A−−, B+

162

20081103

01:22:20

45

01:53:09

315

A−−, B−

167

20081113

16:22:20

225

15:23:06

135

A+, B−

172

20081123

22:22:20

270

04:23:02n

270

A+, B−

175

20081208

17:22:20

315

A++

176

20081212

08:22:20

90

08:22:55

270

A−, B+

179

20081227

06:52:20

45

10:52:50

315

A−, B−−

186

20090114

06:22:00

90

11:22:00

270

A+, B−−

188

20090117

14:22:24

90

B+

195

20090210

20:52:00

270,90

01:52:19n

225,90

A+, B−−

198

20090218

09:22:00

90

15:22:19

45 – 315

A+, B−−

207

20090316

14:22:00

90,270

12:22:19

90,270

A−−, B+

208

20090318

00:22:00

90

07:22:19

315

A+, B−−

213

20090326

09:22:00

270

19:22:20

135

A+, B+

217

20090410

19:22:00

270

A+

226

20090423

00:22:00

90,315

00:22:26

90

A+, B−

228

20090502

23:22:00

270

20:22:28

90

A−−, B+

234

20090521

19:22:35

135

B+

243

20090613

13:52:00

90

14:52:43

270

A+, B−

244

20090615

02:52:00n

90

21:22:43

270

A+, B−

245

20090616

16:52:00

270

16:52:44

270

A+, B−

259

20090723

08:22:00

270

06:52:49

90

A−, B+

262

20090804

18:22:00

90

18:22:49

270

A+, B+

263

20090808

16:52:00

90

22:22:49

90

A+, B−−

264

20090811

14:22:49

90

20:22:00

270

A−, B++

265

20090813

03:22:00

270

A+

267

20090819

03:08:15

270

05:09:04

90

A+, B−

271

20090903

12:08:15

90

05:09:04

270

A−, B+

288

20091031

05:08:15

90

05:09:04

270

A−, B+

291

20091108

05:08:15

270

06:09:04

45

A++, B−

293

20091115

13:08:15

270

A−

299

20091121

08:08:15

90

11:09:04

270

A++, B−−

307

20091216

03:08:15

90

04:08:58

270

A+, B−

325m

20100201

23:08:15

135 – 270

22:09:04

225

A−−, B++

333m

20100211

21:08:15

90

23:08:41

270

A−, B++

337m

20100214

08:08:15

45

05:08:40

270

A−, B+

347m

20100225

01:08:15

135,225

02:08:38

225,45

A++, B−

350m

20100228

18:08:15

315

19:08:37

45

A++, B+

351m

20100301

09:08:15

135 – 180

08:08:37

225

A−, B+

359m

20100309

08:08:15

270

12:08:36

90

A+, B−

365m

20100314

13:08:15

225

14:08:36

90

A−, B++

369m

20100319

20:08:15

90

21:08:35

270

A+, B++

370m

20100320

09:08:15

270

11:08:35

315 – 135

A++, B−

373m

20100326

16:08:15

90

17:08:35

270

A−, B+

376m

20100329

12:08:15

270

14:08:35

90

A+, B−

377m

20100330

12:08:15

135,315

14:08:35

45,225

A++, B+

379m

20100403

11:08:15

135

12:08:35

225

A++, B++

383m

20100408

09:08:15

90

07:08:36

270

A+, B−

386m

20100411

09:08:15

225

11:08:36

135

A+, B−

387m

20100412

10:08:15

225

13:08:36

135

A−, B−−

389m

20100413

15:08:15

45

14:08:36

315

A−, B++

391m

20100419

05:08:15

135

04:08:36

225

A−, B+

392m

20100419

23:08:15

45

00:08:37n

315

A−, B++

404m

20100506

01:08:15

180

02:08:39

225

A−, B+

415m

20100523

00:08:15

270

00:08:43

90

A+, B−

416m

20100523

21:08:15

90

22:08:43

270

A+, B++

418m

20100524

17:08:15

90

17:08:43

270

A−, B+

426m

20100604

16:08:15

270

16:08:46

90

A+, B++

429m

20100612

16:08:15

45

18:08:49

0

A+, B−

432m

20100615

03:08:15

225,45

04:08:49

135,0

A+, B+

434m

20100616

19:08:15

90

20:08:50

270

A+, B−

435m

20100619

03:08:15

315

04:08:51

45

A+, B−−

437m

20100620

22:08:15

90

23:08:15

270

A−, B−

444m

20100703

07:08:15

270

08:08:55

90

A+, B++

445m

20100703

13:08:15

180,90

14:08:55

225,315

A+, B+

448m

20100705

21:08:15

315

20:08:56

45

A+, B−

449m

20100706

08:08:15

90,360

09:08:56

270

A−−, B+

464m

20100801

04:08:15

90

05:09:04

270

A−, B−−

465a m

20100801

09:08:15

90

10:09:04

315

A+, B++

465b m

20100801

08:08:15

45

10:08:15

315

A−, B−

470m

20100807

20:08:15

90,225

21:09:05

270

A++, B++, H

471m

20100808

17:08:15

225

18:09:06

135

A+, B+

474m

20100814

12:08:15

135

13:09:07

225 – 270

A+, B+, H

476m

20100815

14:08:15

45

16:09:07

315

A+, B−

479m

20100818

06:08:15

45

07:09:08

315

A+, B+

500m

20100911

06:08:15

45,225

07:09:12

315,135

A+, B+

511m

20101001

05:08:15

315

06:09:14

45

A++, B+

515m

20101006

10:08:15

90

14:09:14

270

A+, B+

516m

20101007

15:08:15

0

16:09:14

0

A+, B+

519m

20101011

05:08:15

90

06:09:14

270

A++, B++

525m

20101026

15:08:15

135,315

16:09:14

225,0

A++, B+

528m

20101028

16:08:15

215

15:09:13

90

A++, B++

546m

20101116

14:08:15

135

15:09:11

225

A+, B−

551m

20101124

09:08:15

135

10:09:10

270

A−, B+

552

20101126

00:08:15

225

01:09:10

135

A+, B+

558

20101202

13:08:15

270

16:09:09

90

A−, B−

561

20101206

00:08:15n

135

23:09:08

225

A++, B+

566

20101212

08:08:15

45,135

10:09:06

225,315

A+, B+,pH

568

20101214

18:08:15

45

19:09:06

315

A+, B+

574

20101223

12:08:15

90

13:09:04

270

A+, B+

576

20101226

09:08:15

225

10:09:03

135

A++, B++

One event was found in the synoptic movies subsequently, it was labeled with 465b and the previously found event 465 with 465a.

Fit results of the modeled “Best-of” events:
Table 4

Fit results of the 51 modeled events which are listed in Table 3. No indicates the CME-Number in the COR2 list, the six following parameters are the same introduced in Section 2 and summarized in Table 1. The last column denotes the timestamp of the COR2 image used for fitting.

No

ϕ [deg]

θ [deg]

γ [deg]

h front r sun

κ

α [deg]

Time of modeling yyyymmdd-hhmmss

325

39.132

−18.446

15.091

16.786

0.277

23.198

20100201 – 210815

333

219.132

−15.653

−22.919

11.714

0.234

16.491

20100211 – 230815

337

197.888

11.180

−27.392

12.214

0.330

17.888

20100214 – 050815

347

339.876

−24.037

−19.566

13.071

0.336

18.167

20100225 – 000815

350

144.223

36.335

1.118

11.714

0.517

28.229

20100228 – 180815

351

19.008

−19.008

5.031

14.714

0.397

18.167

20100301 – 070815

359

48.074

12.857

−13.415

13.143

0.333

18.726

20100309 – 110815

365

19.008

−8.384

2.236

13.786

0.376

11.180

20100314 – 130815

369

106.211

−11.740

−6.709

13.714

0.385

18.726

20100319 – 200815

370

205.715

12.857

−24.037

12.214

0.597

40.528

20100320 – 090815

373

21.244

−1.118

−39.690

15.000

0.244

9.783

20100326 – 170815

376

126.335

1.678

25.715

11.857

0.388

22.640

20100329 – 120815

377

253.789

−28.510

−16.771

15.000

0.410

14.533

20100330 – 140815

379

258.260

−26.273

−1.118

13.643

0.419

16.491

20100403 – 120815

383

195.653

−1.678

8.383

14.928

0.367

16.211

20100408 – 080815

386

326.459

−15.093

23.477

12.214

0.394

16.771

20100411 – 080815

387

266.087

−25.155

−29.630

13.429

0.244

9.783

20100412 – 110815

389

159.876

35.217

−21.803

14.786

0.499

17.888

20100413 – 150815

391

91.678

−21.242

12.857

13.357

0.514

15.932

20100419 – 040815

392

86.087

26.271

−27.950

15.286

0.622

10.901

20100420 – 000815

404

251.554

−24.597

90.000

15.500

0.665

11.460

20100506 – 020815

415

125.215

−0.560

−32.422

12.072

0.336

11.739

20100523 – 000815

416

320.868

7.826

−9.506

12.857

0.480

13.975

20100523 – 220815

418

304.099

−3.913

−31.304

11.929

0.520

20.123

20100524 – 170815

426

319.752

2.236

28.510

14.429

0.333

26.553

20100604 – 160815

429

336.521

30.186

−40.810

16.286

0.327

6.149

20100612 – 180815

432

228.074

−30.186

−7.267

14.571

0.351

24.317

20100615 – 050815

434

326.459

2.795

−7.828

14.000

0.262

24.595

20100616 – 210815

435

98.381

20.124

−23.477

13.214

0.311

18.726

20100619 – 040815

437

305.219

10.622

2.236

13.714

0.213

15.652

20100621 – 030815

444

346.583

10.062

−22.919

14.928

0.428

14.255

20100703 – 080815

445

205.715

−26.273

1.118

18.072

0.284

15.373

20100703 – 140815

448

320.868

40.806

−40.250

12.643

0.434

13.975

20100705 – 210815

449

134.161

−5.031

−21.242

14.000

0.268

9.783

20100706 – 100815

464

102.856

7.267

36.335

12.000

0.127

11.739

20100801 – 060815

465a

79.380

13.415

−67.640

14.000

0.729

23.198

20100801 – 100815

465b

135.281

32.981

−15.653

4.857

0.271

16.211

20100801 – 100815

470

324.223

−1.118

−32.422

21.857

0.539

8.663

20100807 – 210815

471

200.124

−22.919

2.795

12.857

0.431

23.478

20100808 – 180815

474

353.293

−5.031

3.353

14.357

0.816

31.025

20100814 – 120815

476

310.806

32.981

−25.155

15.214

0.373

21.522

20100815 – 150815

479

348.818

−6.709

−43.043

16.071

0.717

12.019

20100818 – 070815

500

264.967

22.360

2.795

13.214

0.579

19.565

20100911 – 070815

511

176.645

42.484

−1.118

14.714

0.299

22.919

20101001 – 050815

515

280.620

21.802

−4.471

9.429

0.345

20.404

20101006 – 100815

516

8.942

45.279

23.477

13.214

0.357

37.174

20101007 – 150815

519

225.839

6.709

−41.366

13.571

0.523

35.496

20101011 – 060815

525

69.318

−25.715

−40.810

13.357

0.545

11.739

20101026 – 140815

528

205.715

−17.888

2.795

10.572

0.487

35.217

20101028 – 150815

546

86.087

−25.715

−2.795

12.857

0.382

19.286

20101116 – 150815

551

22.360

−21.803

22.919

13.786

0.397

22.361

20101124 – 090815

Copyright information

© The Author(s) 2012