Habitable Exoplanets

 

by Maddie Meagher

The idea of finding a planet like Earth is a very exciting one to me and many others. However there are many factors that go into just making a planet suitable for life, factors such as location, temperature, water, atmosphere, and many others. Today I’m looking at some factors that play role in finding habitable exoplanets, or Earth 2.0 candidates as I like to call them. The main one I’m talking about today is the habitable zone. The habitable zone is the area around a star that a planet can have liquid water. The habitable zone is different for every solar system and is dependent on the parent star. Too close to the parent star and expect to have your oceans be boiled off. Too far and your planet would a giant ball of ice. The data I’m using for this little project comes from a site called the Habitable Zone. The site’s main purpose is to catalog planets in habitable zones and planetary equilibrium temperatures as well as many other various traits of planets.

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These are the boundaries for the habitable zone for our own solar system. The two estimated ranges for habitable zone models in our solar system are the Conservative model from 0.95-1.4AU and the  Optimistic model from .85-1.7AU (Note an AU is the average Earth-Sun distance).

 

 

 

What I wanted to compare was how the location of an exoplanet can affect the planet’s average temperature. To get my data for locations of exoplanets I looked at the optimistic model for the habitable zone. The optimistic habitable zone extends the inner/outer boundaries of a solar system by using the “Recent Venus”(closer to parent star) and “Early Mars”(farther from parent star) criteria. The more optimistic estimate refers to assuming the planet has the right atmosphere to help keep in cooler than it should be at the inner edge, and warmer than it should be at the outer edge. The picture above shows our own solar system’s habitable zone with the optimistic habitable zone being in dark green. For temperature I looked at periastron equilibrium temperatures or Teqb in the database I used. The periastron temperature is the average temperature of a planet when it is at it’s closest point to it’s parent star . It’s also important that a planet is well mixed. What that means that it has an atmosphere that can trap heat well enough and have the heat spread evenly across the planet’s surface. For context, our home planet Earth spends 100% of its time in the habitable zone, and is well mixed, with an average temperature of 290K.

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Using the data from the Habitable Zone I made a graph comparing percentage of time spent in the THZO (the optimistic habitable zone,on the x axis) and the Teqb (average periastron temperatures in kelvins on the y axis). And for reference the blue dot represents where our own home planet Earth would sit on this plot. The results I found is that the more time a planet spent in the optimistic habitable zone (THZO) the more temperatures tended to be below at 500 kelvin, they also tend to fall into the 200-300 kelvin range which is habitable (300 kelvins being a nice warm 80.33 degrees Fahrenheit). This is especially true for those planets who spent 100% of their time the Optimistic habitable zone. Though I noticed three big outliers on the graph. One  is a planet at 1457.4 kelvin (HD 20782 b) and the other at 1547.9 kelvin (HD 80606 b). Both these measurements are above 1400 kelvins or 2060.33 degrees Fahrenheit! However these two planets only spent very little time in the optimistic habitable zone as well as having some rather eccentric orbits (which I show below). The last outlier (HD 43197 b) spent more than 75% of its time in the habitable zone however temperature managed to reach 735.4 kelvins. The one thing all these planets have in common is that during their orbits they travel dangerously close to their parent star. This may contribute to the high periastron temperatures these planets.

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Caption for three pictures above: All three of the exoplanets above for part of their orbit travel dangerously close to their parent star which is most likely the cause of the high spikes in their temperatures seen on the graph above. HD 20782 b doesn’t even spend all of it’s orbit too close to parent star or in the habitable zone. HD 20782 b spends a part of it’s orbit on the outer edge of the planets habitable zone where I would expect it temperature to drop.

Sources used:

http://www.lpi.usra.edu/education/explore/our_place/hab_ref_table.pdf

http://www.exoplanets.org/

http://www.hzgallery.org/index.html

http://www.astronomy.ohio-state.edu/~pogge/Ast161/Unit7/life.html

http://adsabs.harvard.edu/abs/2012PASP..124..323K

Endangered Species

by Kristian Marinez

 lemur Mouse lemur contemplating its existence.

Who global warming affects.

When most people think of endangered mammals threatened by global warming they think of polar bears on melting glaciers. That’s not the most serious case. Most endangered mammals are actually tropical animals in warm climates. Instead of a polar bear being endangered from global warming it can most likely be a mouse lemur in Madagascar. I am interested in the endangerment of mammals simply because they are breathtaking creatures. They think and feel just like us humans do and it’s a shame that a whole lot of them are endangered. It’s interesting to find out the reason for their endangerment instead of just knowing that they’re endangered.

 

Where mammals are endangered and how many are endangered.

The data to support the reasons for mammals endangerment come from the World Bank and informs us with how many mammals are endangered and in which regions endangered mammals can be found. The graph below shows the highest numbers of endangered mammal species (organized from greatest to least) and their region. The  two regions with the most endangered mammal species are East Asia & the Pacific and Sub-Saharan Africa. These regions have a staggering 891 endangered mammals each. The third highest region, Latin America & Central Asia, has 640 endangered mammals. The fourth highest region with the amount of endangered mammals is Europe & Central Asia, with 307 endangered mammals. The three regions with the least amount of endangered mammals have less than 300 mammals each. South Asia has 249 mammals, Arab world has 217 mammals, and Middle East & North Africa have 203 mammals.

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How global warming affects endangered mammals.

From this data, there is a noticeable pattern of a high number of mammals endangered in hot/tropical regions, like Mexico, Madagascar, and Asia, as compared to cooler regions like the Middle East & North Africa. We notice this trend because an increase in temperature (like that caused by global warming) by even a small amount can affect mammals in tropical climates since they are less resilient to heat change. This is because these species are accustomed to living in a certain temperature range, and once this range is surpassed, these animals have a hard time living. For example, global warming cause mouse lemurs to shift habitats and find a different way to obtain food than before.

 

Sources:

http://www.bbc.com/earth/story/20150226-what-hope-is-there-for-madagascars-threatened-lemurs

http://www.dailygalaxy.com/my_weblog/2009/03/global-warmings.html

http://data.worldbank.org/indicator/EN.MAM.THRD.NO

http://a-z-animals.com/animals/grey-mouse-lemur/pictures/4167/

Light Pollution

by Maritza Hernandez

The Globe at Night is a worldwide citizen science campaign to raise public awareness on the impact of light pollution on energy consumption, wildlife, and human health. Globe at Night asks citizen scientists to measure the night sky brightness from their location and add their data to a map on the website.

Light pollution is being caused by us humans because we use to much light. We can’t see the stars because we use too much light to light up buildings, sidewalks, and other things , and by using too much light we are not letting other people or animals see the night sky. Wildlife is being affected by this too because if birds cannot see the stars then they can fly into the buildings and other birds may get confused about when the season is changing. Humans are being affected by this too, light affects when we sleep and artificial light can mess that up. Some of the effects of light pollution include increased risks for obesity, depression, sleep disorders, diabetes, breast cancer and more.

I love seeing the sky with the stars it’s just relaxing,  many people love to just lay back and watch the stars. But if one group is really being affected by light pollution, it is astronomers. If they can’t see the stars then what’s point of being an astronomer! The study of stars is something that I love to learn about so I hope this post makes you care about light pollution.

Globe at Night has been gathering data for the past 9 years from 115 countries. In Globe at Night, citizen scientists look at the sky to see which stars they can see. Then the citizen would send their the data to the Globe at Night team. I found the data for the year 2015 on The Globe at Night website and I downloaded it. Then I sorted the data to display the countries that had the most contributions to the project, and finally I plotted the top 15 countries that participated. The graph that you’re about to see shows that people do care about light pollution effects. For an example, people in Croatia provided the most light pollution data to Globe at Night (nearly 2400 entries). The more people know about this, the faster we can cut down on casualties of birds, on how much energy we use, and the disruption of our sleeping habits.

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This chart shows you the top 15 countries that participated in Globe at Night in 2015.

Sources Used:

“Human Health.” International Dark-Sky Association. 2014. Web. 01 Apr. 2016. <http://darksky.org/light-pollution/human-health/>.

“Light Pollution Taking Toll on Wildlife, Eco-Groups Say.” National Geographic. National Geographic Society. Web. 01 Apr. 2016. <http://news.nationalgeographic.com/news/2003/04/0417_030417_tvlightpollution.html>.

“Light Pollution Wastes Energy and Money.” International Dark-Sky Association. 2014. Web. 01 Apr. 2016. <http://darksky.org/light-pollution/energy-waste/>.

“Globe at Night – Maps and Results.” Globe at Night – Maps and Results. Web. 01 Apr. 2016. <http://www.globeatnight.org/maps.php>.

Global Warming: The Importance of Going Green

by David Torrejon

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                                                                              credit: http://www.storypick.com/save-the-earth/

 

Global warming is an issue that poses an urgent threat to society. Global warming is the gradual increase in temperature on the Earth’s surface. The Earth has suffered irreversible damage at the hands of global warming. The Earth’s average temperature has increased 0.4 to 0.8 Celsius over the course of 50 years. A major cause of global warming is carbon dioxide in the atmosphere and there are two main processes that contribute to increased carbon dioxide, deforestation and the burning of fossil fuels. Deforestation is the process of cutting down trees in order to clear the land. Since trees use carbon dioxide and give off oxygen, this helps create a good balance of gases in the atmosphere so if more forests are cut down, there will be fewer trees to complete this function. Burning fossil fuels impacts global warming because whenever people are burning fossil fuels, they are releasing carbon dioxide into the air. The carbon dioxide goes into the Earth’s atmosphere, which could potentially disturb the natural balance of carbon. The carbon dioxide trap the heat and cause the temperature to get hotter.

Fossil fuels are concentrated organic compound that was formed from the remains of plants and animals millions of years ago. The burning of fossil fuels such as petroleum, coal and natural gas, originates from multiple sources. Most commonly, fossil fuels are used to fuel and provide our everyday transportation, to generate electricity to power house and to provide heat. This graph, which I made from public data from NASA on 2011 carbon dioxide emission, has countries on the X- axis and has carbon dioxide emission in millions of metric tons on the Y-axis. Based on this graph, it can revealed which nations are responsible for the high quality of carbon dioxide in our atmosphere. China, which ranked number one according to carbon dioxide emission, released 8715.34 million metric tons of carbon dioxide. The United States came in second place with 5490.63 million metric tons of carbon dioxide.

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Figure 1: This graph provides information about the amount of carbon dioxide each country releases into the Earth’s atmosphere

The rapidly and drastic increasing of carbon dioxide will have a profound impact on the Earth. This graph, which I made from UCS (Union of Concerned Scientists) on Global Temperature, the year is the X-axis while the temperature anomaly is on the Y-axis. The temperature anomaly means a difference from an average. A positive anomaly indicates that the temperature was warmer than what it should be ,while a negative anomaly indicates that the temperature was cooler than it was supposed to be. The trend for the graph is that as the years have increased the temperature anomaly have increased positively.

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Figure 2: This graphs provides you the difference temperature relative to the average each year

You may ask yourself, why should I care? Well the truth is that economical, environmental and health consequences will only continue to develop if the trend continues. For example, there will be a rise in sea level since the ice is melting at a rapid pace. Global warming will only continue the internal migration of animals. Animals in the North and South Poles will move even further north and further south. Diseases tend to thrive in warm temperatures and have been limited to the subtropical and tropical areas. However, with rise of global temperature, diseases will soon be able to blossom anywhere. Plants and animals will die because of exposure to diseases. Although the damage to the Earth’s atmosphere is irreparable, the carbon emission must go down otherwise life on Earth will only get worse. Our society needs to stop taking this planet for granted. Our society needs to have our political leaders work together to preserve the Earth, after all there is only one planet suitable for human life.

Bibliography:
1.”Each Country’s Share of CO2 Emissions.” Union of Concerned Scientists. N.p., n.d. Web. 01 Apr. 2016.
http://www.ucsusa.org/global_warming/science_and_impacts/science/each-countrys-share-of-co2.html#.Vwg0FBMrKT8
2. “Vital Signs: Global Temperature.” Climate Change: Vital Signs of the Planet. N.p., n.d. Web. 01 Apr. 2016.
http://climate.nasa.gov/vital-signs/global-temperature/

Radio Galaxy Zoo and Black Holes

by Maritza Hernandez (a 2016 Adler Astro-Journalist)

Black holes are always found in the center of galaxies and we need help to discover them. There are two ways to find a black hole. One way to find a black hole would be by their gravitational influence. For example, we could find stars rotating around a black hole. The second way to find a black hole would be observing matter falling into the black hole. The more massive galaxies have bigger black holes in them, and generally the bigger the black hole is, the easier it is to locate. Bigger (more massive) black holes can eat more matter, and when a black hole eats matter it can create jets of material and those jets can travel close to the speed of light. You can detect these jets of material by a radio telescope than we can guess the location of the black hole.

On the Radio Galaxy Zoo site, they combine radio images with infrared images to find these black holes and their jets. Most of the radio images come from the Faint Images of the Radio Sky Twenty- Centimeters or for short FIRST, but also they come from the Very Large Array (aka VLA) telescope in New Mexico. The infrared images come from the Wide-Field Infrared Survey Explorer (aka WISE) and also the Spitzer Space Telescope. Radio images comes from the jets and the infrared comes from galaxies. Infrared is the color that dust glows bright in and of course galaxies have a lot of dust. Radio Galaxy Zoo needs your help to line up the images of the jets with the galaxies to help you to find a complete black hole system. But make sure that the jets look like they are coming from the black hole/galaxy.

We need your help to find these black holes! The Radio Galaxy Zoo team hopes that you can help astronomers learn how black holes are formed, how they are found, and much more. They try to use computers to find these black holes and their material jets. But what if the computers can’t do the job? Well, it’s hard for the computers to tell whether the jets are coming from a certain galaxy. Some other reasons that they want to find black holes are that we want to know what goes on inside of a black hole and why is it that time is affected by the black hole. We also want to know what role a black hole plays in unfolding the universe.

Planet Four: Terrains!

by Kristian Marinez (a 2016 Adler Astro-Journalist)

The goal of the project, Planet Four: Terrains, is to have citizen scientists (average people who probably don’t work in the field of science) review the terrain of the South Pole of the 4th planet in the Solar System, Mars. The terrain is usually formed by the melting of CO2 and ice in the polar ice caps during summer and spring. The images reviewed by the citizen scientists come from Context Camera aboard the Mars Reconnaissance Orbiter. In other words , the images come from a camera that takes pictures of Mars’ terrain from orbit. With the feedback citizen scientists give back, the team will send out the HiRISE (the highest resolution camera ever sent out into space) to new interesting areas of Mars to analyze and see how the terrain changes over time. But features of the terrain are being studied? In the Martian terrain, we can find “Spiders”/“Baby Spiders” and the “Swiss Cheese Terrain”.

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Examples of Spiders and Baby Spiders – Image Credit:NASA/JPL-Caltech/Malin Space Science System , taken from the Planet Four Terrains Research Page

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Example diagram of how spiders are formed, original figure from Piqueux et al., 2003, taken from the Planet Four Terrains Research Page

Spiders (not real arachnids, just terrain that has an image like spiders) is just a name for shallow, patternized channels (passages) on the surface of Mars. These channels are several meters deep and vary in size concerning width. Spiders form when dry ice (carbon dioxide ice) forms in the South Pole. When the Spring season come around, sunlight penetrates the ground, causing the ice to turn into gas from the bottom up. The gas then gets trapped in a layer of ice. When a crack forms in the terrain, the gas erupts out of the opening and also carries loose materials out. Finally, when Summer comes around, the CO2 evaporates and the material on the ground is no longer visible. This happens again in the Autumn and slowly erodes channels in the ground, which are the spiders. The actual term for Spiders is araneiform. Baby Spiders are just the beginning features of the spiders.

The Swiss Cheese Terrain are curvy pits in the surface of thin layers of CO2 ice. Basically, Swiss Cheese Terrain pops up because of repeated cycles of condensation (gas to liquid) and sublimation (solid to gas without going through the liquid stage) of CO2. Thin layers of CO2 ice deposit in excess amounts on some areas. The ice sublimes (solid changed to vapor when heated) and a new layer appears. Areas with no sunlight accumulate CO2 while areas with sunlight lose CO2. This causes irregularities in the terrain. Eventually, pits appear in the CO2 layer. The pits absorb a large quantity of CO2 and they grow.

After a lot of scientific explanations and what not, the goal of Planet Four: Terrain is pretty simple: it’s to give back feedback on the images of the terrain of the South Pole in Mars to analyze and notice how the terrain changes over time.

To learn more, check out the Planet Four: Terrain Blog:).

Disk Detective

by Maddie Meagher (a 2016 Adler Astro-Journalist)

Trying to find planets forming around stars can be quite a daunting task even with the best technology available. This is where a Zooniverse citizen science project called Disk Detective comes in. It’s main goal is to find planets around other stars as well as finding planets in the process of forming. Currently we know very little about how exactly planet formation takes place. What we do know is that planets form around their parent stars in rotating vast gigantic disks, made of various gases and large chunks of rock. What we’re looking for in Disk Detective are two of kinds disks, and both types of these disks are the signposts of the planet forming process.

MaddieP1f1 YSO disk
Maddiep1f2 Debris Disk                          

The data for Disk Detective comes from a survey from a NASA satellite mission called WISE (Wide-Field Infrared Survey Explorer). From 2010 to 2011 WISE created maps of the night sky in infrared wavelengths to look for theses disks. As stars with disks around them shine brightly infrared light due the dust in the disks, where a star all by it’s lonesome wouldn’t shine bright in infrared at all. The two major disks astronomers were looking for in these maps are YSO and Debris disks. YSOs have disks mostly made of gas where planets like Jupiter and Saturn can form. These disks are often less than 5 million years old and will tend to form in clusters. In the picture above for the YSO disk (HL Tauri) you can see where planets in development have begun to clear their orbits around their parent star. Seen by the empty bands in the disk.

On the other hand, Debris disks tend to resemble the Kuiper belt in our own solar system, however, on a more massive scale. A Debris disk’s age tends to be about 5 million years and older. They tend to be composed of more rocky and icy materials and they usually orbit around older stars. Rocky planets like Earth are believed to form out these disks by dust moats gathering around a star to form rocks. Collisions of the larger rocky objects eventually snowball in a rocky planet like Earth, Venus, or Mars!

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Image: Distribution of infrared brightnesses (x-axis) for a sample of 84 stars. While most stars cluster around 1, a lot of the stars have a higher amount of infrared emission (further to the right on the x-axis). Stars with planets are shaded as dark gray, while stars without known planets are shaded with light gray. Although stars with known planets make up less than a third of the sample, four of the five stars with the highest infrared brightness have known planets.
Citation: Beichman et al.2005 Astrophysical journal 622: 1160-1170

Keep in mind, in the graph above stars with disks like HL Tauri are most likely not counted in stars with known planet category. As the bands you saw in the picture above are only indirect evidence of planets residing there.

While WISE has taken Thousands of pictures of the night sky to create the most powerful survey for dusty disks ever known, it does not change the fact stars surrounded by a disk can be rather difficult to spot. Stars with a disk aren’t the only objects in the night sky that glow bright in the infrared (ex: galaxies,asteroids,active galaxy nuclei). Even computer algorithms designed to automatically search for these disks are easily thrown off by these sources of confusion. This is why there is a need for citizen scientists to help classify these objects. So that we can make sure that what we’re really looking at stars with disks. Finding these disks and the birthplaces of planets has been a major quest of astronomers for the last three decades. So start classifying and make new discoveries!

Sources:

Disk Detective Tutorial
http://iopscience.iop.org/article/10.1086/428115/pdf
http://www.jpl.nasa.gov/news/news.php?release=2014-032
http://www.jpl.nasa.gov/news/news.php?release=2014-032
http://www.space.com/450-planets-form-mess.html
http://www.centauri-dreams.org/?p=301
http://www.spitzer.caltech.edu/images/2660-ssc2004-22b-Planets-Point-to-Dust
Spectral Energy Distributions (SEDs)