Division of Heliophysics and Space Physics
The Sun
“And in the midst of all bodies the Sun has his seat. (…) It is not without reason that some call him the lantern of the world, others its mind, still others its ruler.” Nicolaus Copernicus
Heliophysics, of which the main subject of research is the Sun, is one of three fields of astronomy performed in the IA UWr. Currently ten scientists converging in the Division of Heliophysics and Space Physics (U. Bąk-Stęślicka, A. Berlicki, R. Falewicz, R. Getko, J. Jakimiec, T. Mrozek, P. Preś, K. Radziszewski, B. Rompolt (ret. prof.), P. Rudawy, and M. Tomczak) research the Sun and the impact of its radiation on the environment.
The most significant currently realized research projects in heliophysics are:
- Analysis of the mechanisms of energy release in solar flares.
- Modeling the behavior and properties of hot flash plasma.
- Searching for mechanisms of solar corona heating, including:
- Study of the oscillations of the solar corona based on observations made during solar eclipses.
- Analysis of flare activity in quiet areas of the Sun.
- Observations of active phenomena (sunspots, prominences, flares) using coronagraphs in Białków and Wrocław together with other ground and satellite observatories. Study of dynamics, kinematics, and morphological changes of solar prominences.
- Forecasting of periodic and quasi-periodic solar phenomena.
- Study of the relationship between solar activity and the parameters of the solar wind and cosmic radiation.
- Study of radio bursts on the Sun.
At the disposal of Wrocław heliophysicists remain the following observation devices: 53-cm Large Coronagraph, 15-cm Horizontal Telescope with a 30-cm Jensch coelostat, and MSDP spectrograph set up in the observatory in Białków as well as the 13-cm Small Coronagraph set up in the IA UWr. They also use satellite observations, most of all from the satellites SOHO, YOHKOH, TRACE, and RHESSI.
Last updated: 7 June 2010.
SAFETY
WARNING: While performing solar observations it is crucial to always remember that all observations are potentially DANGEROUS. It is necessary to take extraordinary precautions in order to avoid permanent eye damage! Observers of solar phenomena visible on its disk must always follow general safety rules stated on this site.
NEVER LOOK STRAIGHT AT THE SUN WITHOUT ADEQUATE EYE PROTECTION – YOU COULD BE BLINDED WITHIN SECONDS!
IF YOU ARE NOT A PROFESSIONAL OBSERVER OF THE SUN, OBSERVE ONLY BY PROJECTION METHOD* I.E. PROJECTING AN IMAGE OF THE SUN ONTO A SCREEN OR USING AN ATTESTED FILTER REDUCING THE SUNLIGHT INTENSITY LEVEL IN THE WHOLE WIDTH RANGE (INCLUDING UV AND IR) TO AN ACCEPTABLE LEVEL.
*opens to a webpage in Polish
NEVER OBSERVE THE SUN DIRECTLY THROUGH A TELESCOPE, BINOCULARS, OR OTHER OPTICAL INSTRUMENTS EVEN IF THEY ARE EQUIPPED WITH SOME FILTER. SUCH OBSERVATIONS CAN BE DONE ONLY BY EXPERIENCED ASTRONOMERS WITH ADEQUATE EQUIPMENT.
EVEN IF YOU ARE AN EXCELLENT OBSERVER OF THE SUN AND USE FILTERS, ALWAYS MAKE SURE YOU USE CORRECT OPTICAL FILTERS TO PROTECT YOUR EYES.
Each person that observes the Sun does it only on their own responsibility. The authors of this website are not liable for the consequences of any actions taken by anyone in relation to observations of the Sun or phenomena on its disk
For most observers, and especially for all who are not particularly experienced amateur astronomers, the only SAFE method of visual observations of solar eclipses is projecting the solar disk onto a screen or using an attested filter reducing the sunlight intensity level in the whole width range (including UV and IR!!!) to an acceptable level.
The page (in Polish) www:// helio. astro. uni. wroc. pl/ helio_ metprojekc. html contains a detailed description of conducting observations of the Sun by an easy and completely safe method of projecting an image onto a screen. This method enables viewing the image of the disk of the Sun by multiple observers at the same time, which makes it perfectly suitable to use during shows for large groups, e.g. schools. Sun image projection was used by many excellent astronomers, among others by Christopher Schneier and Johannes Havelius.
BASIC INFORMATION ABOUT THE SUN
| Radius | 696 260 ± 70 km |
|---|---|
| Mass | (1.9891 ± 0.0012) · 1030 kg |
| Radiation power | (3.845 ± 0.006) · 1026 W |
| Average density | 1408 kg/m3 |
| Effective temperature | 5 777 ± 2.5 K |
| Age | 4.54 · 109 years |
| Central temperature | 15.4 · 106 K |
| Central pressure | 2.37 · 1016 N/m2 |
| Radiant zone radius | 5.15 · 105 km |
| Radiant zone mass | 98% of the mass of the Sun |
| Convective layer thickness | 1.81 · 105 km |
| Convective layer mass | < 1.7% of the mass of the Sun |
| Photosphere thickness | 500 km |
| Photosphere temperature | 5 800 K |
| Minimum temp. layer temperature | 4 200 K |
| Chromosphere temperature | 4 200 K – 25 000 K |
| Chromosphere thickness | ca. 2000 km |
| Transition layer temperature | 25 000 K – 106 K |
| Corona temperature | > 106 K |
| Mean distance Sun – Earth | 149 597 870 ± 2 km |
| Minimum distance Sun – Earth | 147.1 · 106 km (in January) |
| Maximum distance Sun – Earth | 152.1 · 106 km (in July) |
| The period of Earth’s orbit around the Sun | 365d6h9m10s.5 |
