:Issued: 2026 Feb 17 1546 UTC :Product: documentation at http://www.sidc.be/products/bul #--------------------------------------------------------------------# # SIDC Weekly bulletin on Solar and Geomagnetic activity # #--------------------------------------------------------------------# WEEK 1311 from 2026 Feb 09 Solar Active Regions (ARs) and flares --------------- The Solar flaring activity was at low to moderate levels throughout the week, with 21 C-class flares and 7 M-class flares. There were 21 sunspot groups observed on the visible solar disk. SIDC SG 784 (NOAA AR 4366), SIDC SG 790 (NOAA AR 4373) and SIDC SG 762 (NOAA AR 4374) produced most of the flaring activity. The largest flare was a M2.8 flare, peaking on February 09 at 02:27 UTC, which was produced by SIDC SG 784. This region produced 6 of the 7 M-class flares. Coronal mass ejections --------------------- No Earth directed Coronal Mass Ejections (CMEs) were observed throughout the week. Coronal Holes --------------------- One positive polarity (SIDC CH 146) and four negative polarity (SIDC CH 137, 142, 149, & 150) coronal holes were present on the solar disk in the past week. Returning equatorial SIDC Coronal Hole 146 (equatorial coronal hole with a positive polarity) started crossing the central meridian on February 12. (Other crossing times : January 24, January 16) and SIDC Coronal Hole 150 (equatorial coronal hole with a negative polarity) started crossing the central meridian on February 14. Proton flux levels --------------------- The greater than 10 MeV proton flux remained below the 10 pfu threshold throughout the week. Electron fluxes at GEO --------------------- The greater than 2 MeV electron flux, as measured by GOES-19 fluctuated above and below the 1000 pfu threshold from the start of the week until February 15 after which it stayed below the threshold for the rest of the period. The 24-hour electron fluence was at moderate levels at the start of the week until February 13 and then stayed at normal level until the end of the week. Solar wind --------------------- At the beginning of the week, the Earth was inside a slow solar wind regime, with solar wind speeds around 450 km/s and the total interplanetary magnetic field ranging from 4 to 10 nT. The solar wind parameters became disturbed by the arrival of a high-speed stream on February 14 associated with SIDC Coronal Hole 146, with the solar wind speed rising to 722 km/s and the total interplanetary magnetic field to 15 nT, with the Bz reaching a minimum of – 14 nT. The phi-angle was in the negative sector at the start of the week until February 13 when it switched to the positive sector for the rest of the week. Geomagnetism --------------------- The geomagnetic conditions were at quiet to active levels (Kp 1-4 & K BEL 1-4) at the start of the week. They reached minor storm conditions locally (K BEL 5) on February 10 and minor storm conditions globally and locally (Kp 5 & K BEL 5) on February 14. --------------------------------------------------------------------------- DAILY INDICES DATE RC EISN 10CM Ak BKG M X 2026 Feb 09 156 116 144 008 C1.7 1 0 2026 Feb 10 147 118 142 012 C1.1 1 0 2026 Feb 11 /// 099 129 016 C1.1 3 0 2026 Feb 12 /// 082 129 008 B5.7 1 0 2026 Feb 13 095 070 117 018 B4.4 1 0 2026 Feb 14 /// 087 117 016 B4.4 0 0 2026 Feb 15 /// 073 118 028 B3.7 0 0 --------------------------------------------------------------------------- # RC : Sunspot index (Wolf Number) from Catania Observatory (Italy) # EISN : Estimated International Sunspot Number # 10cm : 10.7 cm radioflux (DRAO, Canada) # Ak : Ak Index Wingst (Germany) # BKG : Background GOES X-ray level (NOAA, USA) # M,X : Number of X-ray flares in M and X class, see below (NOAA, USA) --------------------------------------------------------------------------- NOTICEABLE EVENTS SUMMARY DAY BEGIN MAX END LOC XRAY OP 10CM Catania/NOAA RADIO_BURST_TYPES 09 0214 0227 0248 ////// M2.8 10/4366 11 0029 0044 0050 ////// M1.1 10/4366 VI/2 11 0050 0057 0059 ////// M1.3 /////// 10 2356 0009 0020 ////// M1.2 10/4366 11 1247 1312 1325 ////// M1.4 10/4366 12 0229 0240 0250 ////// M1.4 ///4366 III/2 13 0828 0858 0920 N11W16 M1.0 SF 17/4373 VI/2 #--------------------------------------------------------------------# # Solar Influences Data analysis Center - RWC Belgium # # Royal Observatory of Belgium # # # # Website http://www.sidc.be. # # E-mail sidc-support@oma.be # # To unsubscribe http://www.sidc.be/registration/unsub.php # # # # Legal notices: # # - Intellectual Property Rights: # # http://www.astro.oma.be/common/internet/en/data-policy-en.pdf # # - Liability Disclaimer: # # http://www.astro.oma.be/common/internet/en/disclaimer-en.pdf # # - Use and processing of your personal information: # # http://www.astro.oma.be/common/internet/en/privacy-policy-en.pdf # #--------------------------------------------------------------------#