The galactic supernova remnant (SNR) IC 443, often referred to as the Jellyfish Nebula and Sharpless 248 (Sh2-248), is located in the constellation Gemini. It is situated close to the star Eta Geminorum on the ecliptic plane. It is about 5,000 light years away from Earth.
The remnants of a supernova that happened between 3,000 and 30,000 years ago may be found in IC 443. The neutron star CXOU J061705.3+222127, a collapsed remnant of the main core, was most likely produced by the same supernova. One of the most thoroughly researched examples of a supernova remnant interacting with nearby molecular clouds is IC 443.
The angular diameter of IC 443, an extended source, is 50 arcmin (by comparison, the full moon is 30 arcmin across). Its physical size corresponds to a distance from Earth of around 5,000 light-years (1,500 parsecs), or about 70 light-years (20 parsecs).
A prototype example of a shell-like SNR is SN 1006, which consists of two interconnected sub-shells with various centres and radii. The optical and radio morphology of SNRs is shell-like. Originally assigned to IC 443, a third, larger sub-shell has since been identified as G189.6+3.3, a distinct and older (100,000 years) SNR.
An extremely fragile X-ray shell is scarcely discernible, and IC 443's X-ray morphology is notable for being centrally peaked. Unlike plerion remnants, such as the Crab Nebula, the centre pulsar wind nebula does not predominate the inner X-ray emission. It does have a heat source. IC 443 displays characteristics that are quite comparable to the class of mixed morphology SNRs. A massive molecular cloud in the foreground that spans the entire residual body from northwest to southeast strongly absorbs both optical and X-ray light.
The age of the remains is still unknown. The progenitor supernova is generally accepted to have occurred between 3,000 and 30,000 years ago. A plerion nebula was recently discovered by Chandra and XMM-Newton observations, not far from the remnant's southern rim. A neutron star, a by-product of an SN explosion, is the point source close to the nebula's apex. A Type II supernova, the fate of a massive star, is more likely to occur as the progenitor explosion due to the placement in a zone where stars are forming and the presence of a neutron star.
The remnant's form is significantly impacted by the rich and complicated environment in which it is evolving. The area around IC 443 is home to distinct cloud geometries and significant density gradients, according to multi-wavelength measurements. It is known that massive stars have a short lifespan (about 30 million years), dying while still entrenched in the parent cloud. The most massive stars (O-type) probably rid the surrounding space of ionising radiation or strong stellar winds. Early B-type stars, which typically have masses between 8 and 12 solar masses, are unable to do this, and it is likely that when they explode, they interact with the primordial molecular cloud.
Therefore, it is not shocking that the SNR IC 443, which is assumed to be the result of a supernova explosion, formed in such a complicated environment. For instance, a sizable portion of supernova remnants (around 50 out of 265 in the Green catalogue) is located close to dense molecular clouds, and the majority of them (about 60%) exhibit overt signs of interaction with the nearby cloud.
A black channel that spans IC 443 from northwest to the southeast can be seen in both optical and X-ray imaging. It has been noted that quiescent molecular gas emits in that direction, and this is most likely because of a massive molecular cloud that is situated between the remnant and the observer. This is the key factor for the low-energy SNR emission to be extinguished.
The blast wave is interacting with a dense (10,000 cm3) and clumpy molecular cloud in the southeast, causing the shocked gas to emit in the shape of a ring. The cloud has significantly reduced the blast wave's speed, which is currently estimated to be between 30 and 40 km/s. A reliable tracer of the interaction between dense molecular clouds and SNRs, the OH (1720 MHz) maser emission, has been found in this region. Although it is unclear whether a source of gamma-ray radiation is physically connected to the remnant, it is spatially next to IC 443 and the maser emission zone.
The remnants of a supernova that happened between 3,000 and 30,000 years ago may be found in IC 443. The neutron star CXOU J061705.3+222127, a collapsed remnant of the main core, was most likely produced by the same supernova. One of the most thoroughly researched examples of a supernova remnant interacting with nearby molecular clouds is IC 443.
The angular diameter of IC 443, an extended source, is 50 arcmin (by comparison, the full moon is 30 arcmin across). Its physical size corresponds to a distance from Earth of around 5,000 light-years (1,500 parsecs), or about 70 light-years (20 parsecs).
A prototype example of a shell-like SNR is SN 1006, which consists of two interconnected sub-shells with various centres and radii. The optical and radio morphology of SNRs is shell-like. Originally assigned to IC 443, a third, larger sub-shell has since been identified as G189.6+3.3, a distinct and older (100,000 years) SNR.
An extremely fragile X-ray shell is scarcely discernible, and IC 443's X-ray morphology is notable for being centrally peaked. Unlike plerion remnants, such as the Crab Nebula, the centre pulsar wind nebula does not predominate the inner X-ray emission. It does have a heat source. IC 443 displays characteristics that are quite comparable to the class of mixed morphology SNRs. A massive molecular cloud in the foreground that spans the entire residual body from northwest to southeast strongly absorbs both optical and X-ray light.
The age of the remains is still unknown. The progenitor supernova is generally accepted to have occurred between 3,000 and 30,000 years ago. A plerion nebula was recently discovered by Chandra and XMM-Newton observations, not far from the remnant's southern rim. A neutron star, a by-product of an SN explosion, is the point source close to the nebula's apex. A Type II supernova, the fate of a massive star, is more likely to occur as the progenitor explosion due to the placement in a zone where stars are forming and the presence of a neutron star.
The remnant's form is significantly impacted by the rich and complicated environment in which it is evolving. The area around IC 443 is home to distinct cloud geometries and significant density gradients, according to multi-wavelength measurements. It is known that massive stars have a short lifespan (about 30 million years), dying while still entrenched in the parent cloud. The most massive stars (O-type) probably rid the surrounding space of ionising radiation or strong stellar winds. Early B-type stars, which typically have masses between 8 and 12 solar masses, are unable to do this, and it is likely that when they explode, they interact with the primordial molecular cloud.
Therefore, it is not shocking that the SNR IC 443, which is assumed to be the result of a supernova explosion, formed in such a complicated environment. For instance, a sizable portion of supernova remnants (around 50 out of 265 in the Green catalogue) is located close to dense molecular clouds, and the majority of them (about 60%) exhibit overt signs of interaction with the nearby cloud.
A black channel that spans IC 443 from northwest to the southeast can be seen in both optical and X-ray imaging. It has been noted that quiescent molecular gas emits in that direction, and this is most likely because of a massive molecular cloud that is situated between the remnant and the observer. This is the key factor for the low-energy SNR emission to be extinguished.
The blast wave is interacting with a dense (10,000 cm3) and clumpy molecular cloud in the southeast, causing the shocked gas to emit in the shape of a ring. The cloud has significantly reduced the blast wave's speed, which is currently estimated to be between 30 and 40 km/s. A reliable tracer of the interaction between dense molecular clouds and SNRs, the OH (1720 MHz) maser emission, has been found in this region. Although it is unclear whether a source of gamma-ray radiation is physically connected to the remnant, it is spatially next to IC 443 and the maser emission zone.
The total data collected on this target is just over 2 hours at 180-sec sub-exposure. my equipment used for this is the following;
The data were stacked in Deep Sky Stacker and processed in PixInsight. to give the following picture.
Several add-ons in PI were also used to help with Noise and dark structures.
- Scope – Celestron RASA 8
- Mount - Skywatcher EQ6 R Pro
- Guide scope – ZWO 30mm
- Guide Camera – ZWO ASI 120mm mini
- Main Camera – ZWO Asi 533mc Pro
- Control box – ZWO ASIAIR Pro
- Filter – IDAS NBZ Nebula Booster 2”/ Celestron L-Pro 2”
- Starizona Filter drawer next to the camera sensor
- Fox Halo 96k power bank
- Dew heater with its own power bank on the guide scope
The data were stacked in Deep Sky Stacker and processed in PixInsight. to give the following picture.
Several add-ons in PI were also used to help with Noise and dark structures.
IC443 - the Jellyfish Nebula. 2 hours of data at 180 sec sub-exposure.