S3 EP8: Messier 40, an Optical Double Star

Hello and welcome back. Today Season 3 ends here and with that my journey with this podcast. In this final episode, we will travel to Messier 40 which is also known as Optical Double Star in astronomy. Is it because its a binary star or something else? I will answer that as well. It is also known as "Messier’s Mistake" and there is a very interesting story behind it.Before we dive into why this object is a mistake, let’s first understand what the Messier Catalog actually is. Back in the 18th century, a famous French astronomer named Charles Messier was a passionate about comet hunting. But he kept getting frustrated as whenever he would point his telescope at the sky, he would see a fuzzy object, and think he found a new comet, only to realize it was a nebula, a star cluster, or a galaxy. To prevent other astronomers from making the same mistake, he compiled a list of 110 deep-sky objects to avoid.But entry number 40 is completely different. It isn't a deep-sky object at all. It is just a pair of stars sitting right next to each other.
Now, you might be wondering, how did a simple pair of stars end up in this catalog? Fear not, let me break down the history for you in simple words. In the 17th century, a Polish astronomer named Johannes Hevelius reported seeing a fuzzy cloud in the sky. Fast forward to October 1764, Charles decided to look for Hevelius's nebula. He pointed his telescope at the coordinates, but he couldn't find any fuzziness. Now astronomers think  that what Hevelius was looking at was actually a faint, distant galaxy called NGC 4290, which Messier's telescope simply wasn't powerful enough to see. Instead, all Messier saw at those exact coordinates was a tight pair of stars. He noted it wasn't a nebula but he still logged it into his catalog as M40. So, what exactly is Messier 40? And this is where i will tell you what is an optical double star. Try to imagine that you are standing outside at night. You look down a long street and see two streetlights that look like as if they are touching each other. But as you walk closer, you realize one streetlight is actually right next to you, and the other is on the other side of the road. They only looked close because they lined up perfectly from your view.That is exactly what Messier 40 is. For a very long time, astronomers questioned whether these two stars were a true binary system, meaning they are gravitationally locked and orbit each other or just an optical illusion.The mystery was finally solved recently thanks to high-precision data from the Gaia satellite. The data revealed that the two stars are completely unrelated objects who appear as one from our perspective. 

Now let me tell you more about this interesting object. Messier 40 is located in the constellation Ursa Major. The first star, HD 238107, is an red giant star and the second star, HD 238108, is a main-sequence star like our Sun. They aren't bound by gravity, and they are actively drifting away from each other in different directions. Thank you for being on this journey with me. This was the final episode of Season 3. 

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S3 EP7: IXPE Space Observatory

In today's episode i will tell you all about something that is related to my favorite branch of astronomy. I'm talking about X-ray astronomy and in this episode i will discus about NASA and Italian Space Agency's joint collaborative mission- IXPE space observatory.
IXPE stands for Imaging X-Ray Polarimetry Explorer and was launched in December 9, 2021. Its main goal is to study cosmic objects like black holes and neutron stars such as Magnetars and pulsars that emit huge amount of polarized X-ray radiation. This probe orbits above 600 kms over our planet's equator. IXPE also studies the magnetic fields of supernova remnants. Its observation will help astronomers understand the origin and other stories surrounding these supernova remnants. And that is possible through the studying of its polarized x-rays that these objects emits. "Now you might be wondering, what exactly do I mean by polarized X-rays? Fear not, let me put it into simple words. Light is an electromagnetic wave that vibrates as it travels. Since normal light is made of oscillating electrical and magnetic fields, it vibrates in every possible direction. This is why light from a normal household bulb is unpolarized. But on a cosmic scale, things get extreme. In the intense magnetic environments surrounding black holes and neutron stars, electrons are forced to spin in highly organized tracks. When these particles emit X-rays, the light is born with its vibrations already locked and aligned into just one single direction. That is what we call polarized light. Here is why it is important. Normal x-ray telescopes will just tell you the temperature of an object but they cannot tell you about magnetic fields, shape of a disk around a black hole but a polarized x-ray light can. In February 2022, the first ever images were released of its observations. They were of an supernova remnant called Cassiopeia A. In October 2022, it also observed a gamma ray burst GRB 2221009A, which is sometimes referred to as the 'brightest of all times'.

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S3 EP6: Travelling to Exoplanet HD 80606b

In today's episode, we will talk about an exoplanet located about 217 light years from Earth in the constellation Ursa Major. It’s called HD 80606b and was discovered in 2001 with transit method found to be revolving around HD 80606 star. Before i dive into further details about this exoplanet, i want to tell you about exoplanets. An exoplanet is just like any other planet in our solar system. The only difference is that they don't revolve around our Sun but rather than that they revolve around a whole different star. Unlike the planets in our solar system, which are terrestrial and gas giants only, these exoplanets can be of various types. And HD 80606b is a type of exoplanet called Hot Jupiter. A Hot Jupiter is a gas giant like Jupiter in our solar system. They are physically similar to Jupiter but due to the difference in their orbital periods, they are different from normal gas giants like Jupiter. The closer a planet is to its host star, the faster it revolves. Thus, the Hot Jupiter have small orbital periods, meaning seasons change faster on them. And they are HOTTTT.
HD 80606b mass is about 4 times that of Jupiter but its density is slightly less than that of Earth. Due to its extremely eccentric orbit around the host star, its revolution is just like that of a comet. Sometimes its very closer to the host stars and sometimes due to far stretched out orbit, it is far from the star. This is why it takes 111 days to finish one orbit around HD 80606. To any observer standing on the clouds of this gas giant, its host star would appear 30 times bigger than how Sun appears in our Earth's sky. Computer models have predicted that the temperature change on this exoplanet happens very quickly in just a matter of hours as the temperature could rise up to 280°C. Recently James Webb Space Telescope has discovered that when the planet is close to its star, the temperature skyrockets to 600°C. This was from me for this episode. 

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S3 EP5: Discoveries Made by JWST about Uranus

Hello and welcome back to the episode 5 of Season 3 and today we are ready to venture on a journey to a planet parked in our neighborhood. Today I will tell you about the planet Uranus. Stop laughing. I will also tell you about the findings related to this gas giant by James Webb Space Telescope.

Uranus is the 7th planet from Sun, sitting behind the Saturn and for decades our only visual way to study this frozen world was through a brief flyby made by Voyager 2 in 1986. To humanity, it appeared like a faint blue ball but what happens when you point the most powerful infrared telescope at it? We get new insights on this icy world. In the past, most of the research was being carried out by ground based telescopes or the Hubble Space Telescope. Hubble works in visible light meanwhile ground one worked on radio based astronomy. That is where James came in to help us out. Launched in 2021, this telescope has made groundbreaking discoveries and in the turn of events when it was pointed at Uranus, this is what it discovered. Since this telescope works in infrared spectrum, Uranus glows in that light.

In the images released by NASA and ESA, when Webb’s NIRCam or Near Infrared Camera was pointed at these rings, it successfully captured 11 out of 13 rings of Uranus including the most faint one- Zeta ring. This was not the only thing JWST captured. Instead, it peered deeply into the planet’s thick atmosphere and found something that shattered the old ideas astronomers had about the planet. Astronomers using Webb, mapped the upper atmosphere and the ionosphere of Uranus in a way that has never been done in human history. Because Uranus has a highly asymmetric magnetic field because of its tilting position on side, Auroras here don’t just occur at north and south poles. Instead they shift and dance across different parts of the planet. Webb has detected emission line of a specific molecule called ionized Hydrogen and by tracking this glow, astronomers have successfully mapped the temperature variations in the planet’s upper atmosphere that shows it is cooling down. And the bizarre part about these findings is that unlike what the models predicted, Uranus upper atmosphere is way cooler and is still cooling down. This has unraveled one of the biggest mystery about this planet but has also raised some new questions before the astronomers that we will have to wait for to be answered as more data is gathered through the world’s most powerful infrared telescope.

Now, its facts time and this episode won’t look complete without some random facts about this planet. Uranus is titled at 98 degrees which means it rolls around the Sun on its sides. It’s the only planet in our Solar system doing revolution in such manner. It is the third largest planet in the solar system and takes 84 Earth years to complete one orbit around the Sun. Uranus also had 28 moons.

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S3 EP4: Trojan Asteroids of Jupiter

Hello and welcome back to the new episode 4 of season 3 and today we are embarking on another journey but this time not very distant, only in our neighborhood. As the title suggests I’m going to talk about ‘Trojan Asteroids’ and you might be wondering what they are since most people only know the meaning of term ‘Asteroid’. Are they type of asteroids? Well, I wouldn’t call it that but rather a category of asteroids that is different in its own way and a subject of interest when it comes to understanding the birth of our Solar System. So, without any further wait let’s talk about “Trojan Asteroids”.

Don’t let the title mislead you into believing that Trojan asteroids are formed from Jupiter because it is a gaseous planet. So where do they come from? To understand that let’s understand the concept of Asteroids. These are the leftovers from the Planetary nebula that gave birth to our solar system, meaning after planets were formed, the stuff that could not coalesce into planets, became asteroids. They can be found in the asteroid belt that is located between Mars and Jupiter. There are various theories regarding the birth of these Trojan Asteroids and one of them states that these were formed at the same time, in the same region of planetary disk where Jupiter was forming. While another theory states that these are captured asteroids by Jupiter. This is one of the reasons why sometimes this planet is called the protector of Earth as it continues to protect our planet from getting bombarded by huge asteroids.

There are thousands of such Trojan asteroids lurking around Jupiter but in order for them to be around Jupiter and not crash into the Jupiter itself, they have to have some sort of stability. This is where the concept of Lagrange point comes in. I will not go into much detail about this but all I can tell you that is these are the points around an object in space where the gravity gets cancelled out by the centrifugal force of the object. Thus, creating a point where if any object gets trapped or enters, It will stay locked and won’t go anywhere. This was used in the parking of James Webb Space Telescope, which is at the Lagrange Point 2 of Earth, which is on the further side facing away from the Sun.

Jupiter also has such point and that is where these Trojan Asteroids are located. In fact, they are on two L-points of Jupiter at 60 degree each on L4 and L5 points. In other words, Jupiter has two swarms of asteroids that share the same orbits with planet around the Sun. The first Trojan asteroid discovered was 588 Achilles and was discovered in the year 1906 by German astronomer Max Wolf. Like most of the objects, these are also named after characters in Greek mythology. And these are named after characters in the Trojan war of the same mythology. There are more than 15000 Trojan asteroids that are known so far and according to an estimate the total number of Jupiter Trojans that are above 1 km in size is 1 million. This was from me for this short episode. I will see you next time.

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S3 EP3: A Journey to the Blinking Nebula

Hello and welcome back to episode 3 of Season 3 of this astronomy podcast. Today, we are going on another adventure but this time it’s a journey to a Nebula called Blinking Nebula but before we dive into this, let’s talk about what is a nebula?

Nebula is a place where stars are born. They are usually called stellar nurseries where stars are born in a group. It’s like cultivating seeds of plants in a nursery but in terms of astronomy, stellar nursery is a place where stars are born in a group from a massive cloud of gas and dust. It’s also a place where stars die. In other words, nebula is a part of cycle in which the material gets recycled by the universe. If it still sounds complicated then let me start by giving you an example. Let’s take our Sun. What do you think about how it formed? Has it always been around revolving the supermassive black hole at center of our galaxy? Nebula can be of many types but this is not what we will dive into today. The kind of nebula that I will talk about is a Planetary Nebula. Yes, Blinking Nebula is a Planetary Nebula, also known as NGC 6826 in the NGC astronomical naming catalog. It is also known as Caldwell 15 in the Caldwell catalog. Now you might be wondering about what exactly is a Planetary Nebula. To put it into simple words, a planetary nebula is a nebula formed after the death of a star massive than our Sun in an explosion called Supernova. If a star’s mass is bigger than Chandrasekhar limit, then it will go and become either a black hole or a neutron star as a result of this explosion but since this isn’t a black hole or a neutron star, this is a planetary nebula. In other words, this was formed after a Star with mass less than that limit. To put it into much simpler words, a planetary nebula is an expanding shell of gas and dust into the outer space. It happens when the star runs out of fuel and collapses under the weight of its gravity and since the fate depends on the mass of a star, the star then ends its life in form of a explosion by expanding its shells outwards, leaving a core at the center, which in astronomical terms is called a white dwarf star. It is the third stage of fate for a main-sequence star like our Sun, which means our star too will someday face a death like this. It is the third stage since it comes after the Red Giant phase in which the star expands but doesn’t collapse and goes into explosion. It is after this phase the white dwarf stage arrives. Now that you know the basics, when I’m saying planetary nebula, I meant an expanding cloud of gas and dust after supernova, thus leaving the core of star at the center. Now back to Blinking Nebula.

Blinking Nebula is located about 2200 light years from Earth in the constellation Cygnus. It is referred as the Blinking Nebula because of its pattern of blinking from the observer’s view when viewed through the telescope. What I meant by that is if you were to take a small telescope and see at this nebula directly, the light from the white dwarf HD 186924 will obscure the colorful light of the surrounding nebula. To you, then it won’t appear as a nebula but rather a bright star. However, you can view it with an averted vision. This causes the blinking effect in the eyes of observer as his eyes wanders. It doesn’t actually blink in space. This nebula was discovered in the year 1793 by the astronomer William Herschel and is about only 1000 years old.

This is all from me for this episode. We will meet again with a new episode!

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S3 EP2: Iapetus, Moon of Saturn

Welcome back to episode 2 of Season 3 and today we are going on another adventure but this time it’s far beyond Moon to another Moon in our solar System. Today, I will tell you about a very fascinating moon of Saturn called Iapetus.

Saturn is the second biggest planet but with the largest number of Moons parked around its orbit. As of March 2025, there are a total of 274 known Moons orbiting around Saturn and there could be more in as more data is being processed which was gathered from previously sent missions like Cassini. Iapetus is one of many Moons of Saturn that is known to exist for more than 350 years to us. It was discovered on October 25, 1671 by an Italian astronomer Giovanni Cassini. It was discovered at the Paris Observatory and at the time of discovery was the second known moon of Saturn after Titan which was discovered in 1655. It was also the 6^th known moon found in our solar system. Now moving forward to the story of discovery, which is quite interesting and easy to understand if you know the meaning of the term “tidally-locked”. Okay let me help you recall. In Astronomy, when we say an object is tidally-locked, we mean that it is locked in the orbit of the object it is revolving around. In other words, a tidally locked object is something that only shows its one side towards the object it is facing. The other side remains facing outwards in opposite direction and we can’t see it from our point of view. Still confusing, pardon me for my English but let me try to make it even easier for you with an example. Our own Moon is tidally-locked with Earth because we only see its one side facing us. The other side is dark and facing towards the outer space. The same case is with Iapetus, which is tidally locked with Saturn. This has one of the huge role in the discovery of this moon.

Back in October 1671, when Giovanni Cassini pointed his refractive telescope at Saturn, he discovered an object appearing to be hanging in the orbit around Saturn. This was discovered in the western side of Saturn from our point of view. So when it was revolving around Saturn, it was in the western side and very clear from our point of view. To confirm his predictions, Cassini tried to look for it again few months later but this time it was nowhere to be found on the eastern side. Why was it happening? Did something swallow it? Obviously the concept of black hole was unknown at that time but he tried it again but this time with a much improved telescope. He pointed it again on the eastern side of Saturn and there it was in orbit around Saturn. It had not gone anywhere, it was there the whole time but the reason for it was very easy to understand. The side that was facing towards us on the western side is icy and reflects back a lot of light but on the other side, when it reaches on the eastern side of the planet, we were met with a much darker side that does not reflects any light. However, you must not forget that Iapetus is tidally-locked and only we can observe it’s both sides from our point of view but to anybody standing on the Saturn (only if it was possible), you can only see one side of the Moon.

Iapetus is the third largest moon of Saturn and 11^th largest in our Solar System. Unlike other moons like Europa, it does not have any ocean beneath its icy surface. This icy world is about 1469 km in diameter. A day here is about 79 Earth days long. Apart from these facts, there is one more feature about this Moon which makes it standout against other natural satellites discovered so far. Iapetus is a walnut shaped moon because of an equatorial ridge that runs along the equator for about 1300 km long and it is about 20 km wide and 13km high, much higher than the Mt. Everest on Earth. Because of this height of Ridge and its distance, this gives Iapetus a walnut like shape. Without any hypothesis, this wouldn’t be actually part of Astronomy. So yes there is one that I like the most which is that there used to have a ring system around Iapetus, which later fell around its equator. Thus, the equatorial ridge was formed.

Another question that rises here is have we ever visited this world before? And the answer is both yes and no. There has never been any specific mission to this Moon before but flyby have happened in the part as part of missions like Cassini. The first attempt to study Saturn and its moon happened with Pioneer-11 mission but it didn’t came that closer to it. The next series of mission Voyager-1 and Voyager-2 and with this Voyager-1 made history as it became the first ever spacecraft to ever send back a picture of Iapetus two tone surface. That is the picture gave us more details about its dark and icy sides surface. But the closer study of its surface wouldn’t happen till December 31, 2004 when Cassini spacecraft made its first targeted flyby around Iapetus. The closest and last flyby of Iapetus by Cassini happened in September 2007 and after that it never made any contact with the Moon. Data from Cassini showed that its surface is heavily cratered and has a massive impact basin about 580 km in diameter. This was from me for this month’s story. I will be back next month with another episode. Thank you!

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S3 EP1: NASA's Return to Moon with Artemis-II

What a great time to start the new season. Hi, I’m your host Maanvinder and today we’re going on a journey to the moon. Not physically but just use your imagination and let it run wild. I hope you have already gotten your boarding pass from NASA because I have already got mine. Today’s topic is the Artemis Mission. I have talked about this previously but it was for a blog I no longer contribute to. Sad, right? So, tight your seatbelts because it’s time to take off again.

With Artemis, NASA marks its return to the beautiful moon parked in the orbit of our planet Earth. This is a mission that is to be carried in 3 different programs: Artemis-I, Artemis-II, Artemis-III. Sadly, I was not here to talk about Artemis-I, which had already happened back in the year 2022. It was an uncrewed flight around the orbit of moon. But now I’m here at the right time for Artemis-II. The reason why this mission is called Artemis is because in the Greek mythology Artemis is the goddess of Moon and Apollo is the twin sister of Artemis. Since Apollo was a mission to Moon, NASA decided to call their new mission as Artemis, to keep remembering the contribution from Apollo missions. The main goal of the Artemis mission is to land the first woman and first person of color on the lunar South Pole to study the lunar surface. It is NASA’s first mission in more than 50 years that involves humans and lunar surface. To be exact, the first crewed mission since Apollo 17 in 1972. Before you understand what this Artemis-II mission is about, you need to understand what Artemis-I was about.

Artemis-I which was launched in November 2022 was an uncrewed mission to the Moon, in which NASA tested the Space Launch System- a rocket capable of carrying more than 180,000 kg of weight and Orion Module, which is the most important part related to Artemis-II. It is because this Orion is a spacecraft attached to the Space Launch System (SLS) that will carry the astronauts to the Moon. It will have life support system for the crew of the mission. So what really happened in the Artemis-I? When this mission was first launched, it was to test the SLS and Orion Spacecraft. What happened really was once it was launched into the space; SLS detached itself from Orion, then Orion went on a journey around the Moon and finally ended with its splashdown into the Pacific Ocean. It was a test flight, which means there were no humans onboard. This was a major step to guarantee the success of Artemis-II, since it involves a group of astronauts who will stay in orbit around Moon to study and gather flight data. You should not confuse Artemis-II with humans landing on Moon because it will take time. In simple terms, it is another test flight but with humans onboard. The landing of humans will only happen in Artemis-III program, which is yet to happen based on the results of Artemis-II. The initial date of launch for Artemis-II is February 6, 2026 which might change depending on weather conditions. The mission will last about 10 days by ending the flyby around Moon with a splashdown of Orion into pacific again, while carrying the crew.

Now you might think we are doing this all just to carry some humans into orbit around Moon who won’t even land on surface. But here is the real twist, with this mission NASA is aiming much higher that is a mission to Mars. That is why, after the success of Artemis-II mission, NASA plans to build a station around the orbit of Moon. It will be called “Lunar Gateway, and European Space Agency is working on it with NASA. The main work of this small space station will be to act like a platform for the missions to the Moon or possibly even to the Mars. In this, Astronauts will use Orion to fly and dock with the space station in the orbit and then later transfer into the Lunar Landing Module to get onto the surface of the Moon. Lunar Landing Module is basically a vehicle that will carry astronauts to the surface of the moon. This is basically how Artemis-III will happen. The landing module that was designed for Apollo missions was for only one journey to the Moon’s surface but this one will be used for multiple missions.

Back to Artemis-II, the four astronauts that are set to onboard this are: Reid Wiseman, Victor Glover, Christina Koch and Jeremy Hansen from the Canadian Space Agency. With this Christina will become the first woman to travel to the Moon and Glover will become the first person of color who traveled to Moon. Apart from carrying astronauts, Artemis-II will also be carrying 4 CubeSats from different countries. A CubeSat is a small satellite that is about the size of a shoe-box and is capable of studying the environment of space. The main goal is to deploy these into High Earth Orbit when SLS and Orion are separated.

To summarize this, Artemis-II will be the first mission of NASA in more than 50 years that will carry humans to the Moon. It will be a flyby around our natural satellite that will end with the splashdown into the Pacific Ocean. The success of this mission will decide the trajectory of Artemis-III, which involves landing on the surface of Moon. This is all I have to share with you now. Until we meet again. Stay tuned in.

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