What Would Cause Two Stars To Collide? What Does It Take For A Whole Planet (as Massive As Jupiter) To

Picture of the day - December 6, 2018

Another picture of the fifth planet of the Insight B system.

Another Moon Shot

Picture of the day - October 26, 2018

A large moon against the backdrop of a stunningly colorful gas giant and it’s rings.

Picture of the day - February 6, 2019 - (Very late post)

Ringed ocean world with greenish-gray colored oceans. The Carina Nebula fills the sky in the background.

Pictures of the day - December 20, 2018

Insight A - Fifth Planet (Insight A-V)

Insight A-V is a hot earth-like planet with oceans. The planet does support marine life, but the surface is far too inhospitable for anything other than Extremophiles. The planet is much smaller and less massive than Earth at 0.14 Earth masses and a diameter roughly half that of Earth. The surface is very active with a hot atmosphere. The surface averages 161 F, with an atmosphere only 54% as thick of Earth’s that is dominated by carbon dioxide. The surface is so hot that there are no ice caps or even snow on mountain-tops.

The planet rotates backwards with an axial tilt of 148 degrees and a rotational rate of 24 hours and 21 minutes. No moons orbit the planet.

High Resolution Pictures

Insight A-V

Earth-Like World

Cyclone

The Surface

Polar orbit

Picture of the day - February 15, 2019

Gas giant with vivid violet rings.

The burning sun begins to set behind a large volcano.

Gas Giant Classification System

Note: this is a modified version of the Sudarsky Gas Giant Classification System, which is a system proposed by David Sudarsky to classify gas giant planets, such as Jupiter and Saturn.

The system that Sudarsky created classifies gas giant planets based off of the temperature of the planet’s atmosphere’s at 1 bar pressure, and the primary chemical that comprises the planet’s cloud decks. His original system contained 5 different types of gas giants: Ammonia, Water, Cloudless, Alkali Metal, and Silicate Clouds)

I have decided to amend his original classification system to include three additional types of gas planets (Nitrogen-Oxygen, Methane, and Carbon), and I believe this system should apply generally to ice giants as well. These modifications cover more types of gaseous planets under a greater range of temperatures and compositions. Again credit to the original idea is given to David Sudarsky.

Type Ib: Nitrogen-Oxygen Class Gas/ Ice Giant

Nitrogen-Oxygen Gas/Ice Giants are the coldest types of gaseous planet. They have atmospheric temperatures of less than 40 K, (-388 °F) at 1 bar pressure. These planets have atmospheric temperatures low enough that oxygen and nitrogen condense into liquid droplets and ice crystals, and at lower depths in the atmosphere it rains liquid nitrogen and oxygen. In hydrogen depleted gas/ ice giants, the cloud decks may even be composed of crystals and droplets of carbon monoxide.

These planets have a primarily deep blue color, with dull gray/blue cloud bands. The blue color of the atmosphere is due to the presence of liquid nitrogen and oxygen lower in the atmosphere which scatters blue light. Gaseous planets of this class planets are relatively rare. Gas giants of this class only exist if they are extremely old (8+ Billion years) and orbit far from their parent star. Most gas giants emit enough internal heat to be too warm to fit this class, given the age of the universe. Ice giants of this class would be more common due to their smaller size and smaller reservoirs of internal heat. Rogue ice giants occupy most planets of this class.

Type Ia: Methane Class Gas/Ice Giant

Methane Class Gas/Ice Giants occupy a temperature range between 40 K and 90 K (-388 °F and -298 °F). These planet’s have atmospheric temperatures that support the formation of methane clouds. Methane is the primary light scattering chemical which gives the planet a deep blue to cyan color. Examples of this class include both Neptune and Uranus.

Methane Class gas planets orbit far from their parent stars, and often emit as much heat as they receive from the sun. Atmospheric activity is driven almost entirely by internally released heat. Planet’s with less heat often appear bland and almost featureless (i.e. Uranus), while planets that emit significant internal heat, show more pronounced cloud bands and even large cyclonic systems (i.e. Neptune). The hue of the planet is believed to be determined by how much methane is in the atmosphere.

Type I: Ammonia Class Gas/Ice Giant (Original Sudarsky Type I)

Ammonia Class Gas/Ice Giants occupy a temperature range between 90 K and 160 K (-298 °F and -172 °F). These planet’s have atmospheres dominated by ammonia ice crystals. Ammonia is the primary light scattering compound that often gives these planets a brownish hue. Temperatures are warm enough in the atmosphere for complex chemistry to occur, including for formation of tholins and other complex hydrocarbons, along with various other chemical compounds dredged up through convection from the interior. Cloud bands may take on numerous colors including: brown, white, red, orange and yellow.

Ammonia Gas giants include both the planets Jupiter and Saturn. The atmosphere of an ammonia gas planet is extremely turbulent and active due to the increased solar radiation. These planets typically orbit just beyond a star systems frost line (the temperature at which ice will not sublimate in a vacuum), but not far enough for methane clouds form.

Type II: Water Class Gas/Ice Giant (Original Sudarsky Type II)

Water Class Gas/Ice Giants occupy a temperature range between 160 K and 250 K (-172 °F and -10 °F). These planets have atmospheres dominated by water-ice crystals, and their atmosphere experiences liquid water rain at lower depths. If a gaseous planet were to support aerial life, Type II planets would be the perfect candidate. Water-Ice reflects a lot of the sunlight making these planets extremely bright with high reflective albedos.

No Water Class Gas or Ice giants exist within the solar system, but examples include: Upsilon Andromedae D or PH2B. Type II planets orbit from the middle of the habitable zone out to the edge of the frost line. Type II gaseous planets orbiting within a system’s habitable zone may have large Earth-like satellites in orbit that are capable of supporting life.

Type IIa: Sulfur Class Gas/Ice Giant

Sulfur Class Gas/Ice Giants occupy a temperature range between 250 K and 350 K (-10 °F and 170 °F). These planets have atmospheres dominated by hydrogen sulfide and sulfur. Cloud decks are composed of crystals of hydrogen sulfide and sulfur-dust. These planets have complex upper atmospheric chemistry dominated by sulfur bearing compounds, and have a composition similar to the clouds of Venus. Atomic sulfur dust in the atmosphere gives the planet’s a distinct yellow hue, and is the result of ultraviolet radiation breaking down hydrogen sulfide though a process called photodissociation.

Sulfur Class Gas/Ice Giants orbit between the center of a system’s habitable zone and a system’s Venus Zone. The atmosphere’s of Type IIa planets are extremely active which cyclonic systems, sharp cloud bands, and chaotic polar regions. As with Type II Gas/Ice Giants, Type IIa planets orbiting within a system’s habitable zone may support Earth-like moons in orbit.

Type III: Cloudless Glass Gas/Ice Giant (Original Sudarsky Type III)

Cloudless Class Gas/Ice Giants occupy a temperature range between 350 K and 800 K (170 °F and 980 °F). These planets have atmospheres that do not lie within a temperature range of any common compounds to exist as either ice crystals of liquid droplets. Methane deep in the atmosphere give the planets a blueish green hue from the scattering of blue light. Due to the lack of clouds, the banding is faint and muted in appearance. Varying concentrations of sulfides and chlorides between the individual weather zones give each band a slightly different hue. If high concentrations of sulfur are present, these planets may take on a violet or purple color from the formation of diatomic sulfur molecules.

Cloudless Class Gas/Ice Giants orbit between roughly a mercury equivalent orbit and the inner edge of the Venus Zone. The atmosphere despite it’s faded appearance, experiences powerful winds and extremely stormy weather. Roughly half of these type of planets orbit close enough to their parent stars to be tidally locked.

Type IV: Alkali Metal Class Gas/Ice Giant (Original Sudarsky Type IV)

Alkali Metal Class Gas/Ice Giants occupy a temperature range between 800 K and 1,400 K (980 °F and 2,060 °F). At these temperatures carbon monoxide becomes the dominate carbon-carrying molecule instead of methane. Metals such as sodium and potassium become more common in the atmosphere, condensing into cloud decks. Additionally clouds containing titanium dioxide and vanadium oxide may also form. Type IV planets typically have a monochromatic color, but some may have hues of dark green or dark red, depending on the composition of the clouds. Most have a very low reflective albedo, reflecting less than 5% of the sunlight they receive.

Alkali Metal Class Gas/Ice Giants orbit close to their parent stars, and most are tidally locked to their sun. Extremely violent weather occurs within the atmosphere, and most experience wind speeds of over 1,000 mph. The increased heat also increases the overall diameter of the planet; therefore, Type IV planets are often larger than Types Ib - Type III of the same mass.

Type V: Ferro-Silicate Class Gas/Ice Giant (Original Sudarsky Type V)

Ferro-Sillicate Class Gas/Ice Giants occupy a temperature range between 1,400 K and 2,800 K (2,060 °F and 4,580 °F). These planets are viewed of as the traditional examples of either a Hot Jupiter or Hot Neptune. Temperatures are hot enough that cloud decks of silicates and iron form in the upper atmosphere. It is not uncommon for molten iron and molten glass rain to occur within the atmosphere. The color of these planets varies wildly depending on whether silicates or iron are more common. Type V planets with silicates dominating the cloud decks will appear bright azure blue in color from liquid droplets of glass scattering blue light. Type V planets where iron dominates the cloud decks will have a more gray-red color. The atmosphere is so hot that it glows a dull red.

Ferro-Silicate Gas/Ice Giants orbit very close to their parent stars with orbital periods of a few days or less and are tidally locked to the sun. Their diameters are puffed up by the intense solar radiation, and the planets often have unusually low average densities, lower than that of even Saturn. Weather is wild in the atmosphere, with winds blowing in excess of 2,000 mph. The winds are so fast and transport heat so efficiently that the night side is almost as hot as the day side despite being in perpetual darkness. A prime example of this planet type would be 51 Pegasi B. (Note this was the first type of planet discovered orbiting a sun-like star outside of our solar system). Due to the close proximity to their parent stars, these planets are constantly loosing atmospheric gasses, and appear almost comet-like from the distance.

Type VI: Carbon Class Gas/Ice Giant

Carbon Class Gas/Ice giants occupy a temperature range above 2,800 K (4,580 °F), and are considered to be the rarest type of planet. These planets have cloud decks composed of carbon. Cloud decks of solid carbon crystals will be composed of graphite, while at deeper depths liquid diamond rain will occur. Above 2,800 K most chemical compounds break down into their constituent elements, and the atmosphere of these planets have more in common with that of a star than a planet. The atmosphere is primarily black in color, reflecting less than 1% of the light the planet receives. The planet is only visible because temperatures are hot enough that the atmosphere and clouds glow dim red in color.

Type VI planets orbit close enough to their parent stars that they have orbital periods of less than a day, are tidally locked to the sun, and lose thousands of tons of their atmospheres every second. Very weird chemical reactions occur at the boundary line with the night side, where chemicals such as water are broken into hydrogen and oxygen during the day, and re-condense into water vapor at night. Ice giants of this class would only be short-lived since they are not massive enough to retain their hydrogen-helium atmospheres for more than a few tens of millions of years. Carbon-Class Gas giants can be the largest planets in terms of diameter, their size extremely bloated by intense solar radiation.

This is merely my input on classifying giant type planets, which I use in my hobby of designing my own star systems. If anyone has anything to add, please feel free to do so.

Pictures of the Day - January 18, 2019

2nd set of pictures of this Titan-Like world.

Crowded Worlds

Picture of the Day - October 15, 2018

Alien moon and its parent gas giant, looking towards the sun. This system is located within one of the densely packed globular clusters orbiting Triangulum’s center.

Galaxies: Types and morphology

A galaxy is a gravitationally bound system of stars, stellar remnants, interstellar gas, dust, and dark matter. Galaxies range in size from dwarfs with just a few hundred million (108) stars to giants with one hundred trillion (1014) stars, each orbiting its galaxy’s center of mass.

Galaxies come in three main types: ellipticals, spirals, and irregulars. A slightly more extensive description of galaxy types based on their appearance is given by the Hubble sequence. 

Since the Hubble sequence is entirely based upon visual morphological type (shape), it may miss certain important characteristics of galaxies such as star formation rate in starburst galaxies and activity in the cores of active galaxies.

Ellipticals

The Hubble classification system rates elliptical galaxies on the basis of their ellipticity, ranging from E0, being nearly spherical, up to E7, which is highly elongated. These galaxies have an ellipsoidal profile, giving them an elliptical appearance regardless of the viewing angle. Their appearance shows little structure and they typically have relatively little interstellar matter. Consequently, these galaxies also have a low portion of open clusters and a reduced rate of new star formation. Instead they are dominated by generally older, more evolved stars that are orbiting the common center of gravity in random directions.

Spirals

Spiral galaxies resemble spiraling pinwheels. Though the stars and other visible material contained in such a galaxy lie mostly on a plane, the majority of mass in spiral galaxies exists in a roughly spherical halo of dark matter that extends beyond the visible component, as demonstrated by the universal rotation curve concept.

Spiral galaxies consist of a rotating disk of stars and interstellar medium, along with a central bulge of generally older stars. Extending outward from the bulge are relatively bright arms. In the Hubble classification scheme, spiral galaxies are listed as type S, followed by a letter (a, b, or c) that indicates the degree of tightness of the spiral arms and the size of the central bulge.

Barred spiral galaxy

A majority of spiral galaxies, including our own Milky Way galaxy, have a linear, bar-shaped band of stars that extends outward to either side of the core, then merges into the spiral arm structure. In the Hubble classification scheme, these are designated by an SB, followed by a lower-case letter (a, b or c) that indicates the form of the spiral arms (in the same manner as the categorization of normal spiral galaxies). 

Ring galaxy

A ring galaxy is a galaxy with a circle-like appearance. Hoag’s Object, discovered by Art Hoag in 1950, is an example of a ring galaxy. The ring contains many massive, relatively young blue stars, which are extremely bright. The central region contains relatively little luminous matter. Some astronomers believe that ring galaxies are formed when a smaller galaxy passes through the center of a larger galaxy. Because most of a galaxy consists of empty space, this “collision” rarely results in any actual collisions between stars.

Lenticular galaxy

A lenticular galaxy (denoted S0) is a type of galaxy intermediate between an elliptical (denoted E) and a spiral galaxy in galaxy morphological classification schemes. They contain large-scale discs but they do not have large-scale spiral arms. Lenticular galaxies are disc galaxies that have used up or lost most of their interstellar matter and therefore have very little ongoing star formation. They may, however, retain significant dust in their disks.

Irregular galaxy

An irregular galaxy is a galaxy that does not have a distinct regular shape, unlike a spiral or an elliptical galaxy. Irregular galaxies do not fall into any of the regular classes of the Hubble sequence, and they are often chaotic in appearance, with neither a nuclear bulge nor any trace of spiral arm structure.

Dwarf galaxy

Despite the prominence of large elliptical and spiral galaxies, most galaxies in the Universe are dwarf galaxies. These galaxies are relatively small when compared with other galactic formations, being about one hundredth the size of the Milky Way, containing only a few billion stars. Ultra-compact dwarf galaxies have recently been discovered that are only 100 parsecs across.

Interacting

Interactions between galaxies are relatively frequent, and they can play an important role in galactic evolution. Near misses between galaxies result in warping distortions due to tidal interactions, and may cause some exchange of gas and dust. Collisions occur when two galaxies pass directly through each other and have sufficient relative momentum not to merge.

Starburst

Stars are created within galaxies from a reserve of cold gas that forms into giant molecular clouds. Some galaxies have been observed to form stars at an exceptional rate, which is known as a starburst. If they continue to do so, then they would consume their reserve of gas in a time span less than the lifespan of the galaxy. Hence starburst activity usually lasts for only about ten million years, a relatively brief period in the history of a galaxy.

Active galaxy

A portion of the observable galaxies are classified as active galaxies if the galaxy contains an active galactic nucleus (AGN). A significant portion of the total energy output from the galaxy is emitted by the active galactic nucleus, instead of the stars, dust and interstellar medium of the galaxy.

The standard model for an active galactic nucleus is based upon an accretion disc that forms around a supermassive black hole (SMBH) at the core region of the galaxy. The radiation from an active galactic nucleus results from the gravitational energy of matter as it falls toward the black hole from the disc. In about 10% of these galaxies, a diametrically opposed pair of energetic jets ejects particles from the galaxy core at velocities close to the speed of light. The mechanism for producing these jets is not well understood.

The main known types are: Seyfert galaxies, quasars, Blazars, LINERS and Radio galaxy.

source

images: NASA/ESA, Hubble (via wikipedia)