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May 2017 - Bays Mountain Park
May 2017 - Bays Mountain Park

... Athens. Icarius, who had been favored by Dionysus, was killed by his shepherds while they were intoxicated and Erigone hanged herself in grief. Dionysus placed the father and daughter in the stars as Boötes and Virgo. Interestingly, Virgo is the largest constellation of the Zodiac and the second-lar ...
AST 301 Introduction to Astronomy - University of Texas Astronomy
AST 301 Introduction to Astronomy - University of Texas Astronomy

... We don’t want the flux to depend on what telescope we use to measure it.) The flux of a star depends on how much light it emits and on how far we are from that star. We’ve defined flux so it doesn’t depend on what telescope we use, but it does depend on where the telescope is. ...
Right Ascension
Right Ascension

... When the fuel runs out, the balance between gravity pulling material in and gas pressure pushing it out breaks down. The core begins to contract because energy is no longer being produced. As the core contracts, it gets hotter and hotter, as the pressure increases. What happens next depends on the m ...
astronomy
astronomy

... distances, and the forces that tie them together. Although astronomy began as simply a means of telling time and location, it soon developed into a full-fledged area of study, characterized by patient observation and detailed record-keeping. As early as 2500 BC in what is now England, work began on ...
Stellar Structure - McMurry University
Stellar Structure - McMurry University

... – Example: Wolf-Rayet stars.  >40 solar masses.  Extremely unstable: violent stellar wind eventually ejects outer layers of star.  After core collapse and supernova, very little hydrogen is left in star to create spectral lines. ...
Sample Stellar Evolution TEST QUESTIONS
Sample Stellar Evolution TEST QUESTIONS

... 11. The Orion region contains young main sequence stars and an emission nebula. 12. The thermal motions of the atoms in a gas cloud can make it collapse to form a protostar. 13. The pressure of a gas generally depends on its temperature and its density. 14. Stars swell into giants when hydrogen is e ...
Unpublished draft available in  format
Unpublished draft available in format

... same thing; in the case of stars, any given star may demonstrate a whole string of concepts; e.g. a giant star of a late spectral type (M, R, N, S) may also be a long-period variable. Theoretically it is possible to achieve a class number which compounds all such attributes, but this might be a very ...
SHELL H II REGIONS IN NGC 6334
SHELL H II REGIONS IN NGC 6334

... • Orbital motions in protostars will provide important constraints on the early phases of stellar evolution • We are getting reasonable results, but must follow “strange” cases such as IRAS 162932422 ...
Centimeter and Millimeter Observations of Very Young Binary Systems
Centimeter and Millimeter Observations of Very Young Binary Systems

... • Orbital motions in protostars will provide important constraints on the early phases of stellar evolution • We are getting reasonable results, but must follow “strange” cases such as IRAS 162932422 ...
star - TeacherWeb
star - TeacherWeb

... • Low to Medium Mass -nebula- main sequencered giant- white dwarf- black dwarf • High Mass -nebula- main sequence- red giantsupernova-neutron star and nebula • Very High Mass- nebula- main sequence- red giant- supernova- black hole and new nebula ...
Your Guide to the Universe
Your Guide to the Universe

... to be the brightest object in our Solar System and naturally we are really curious to know more about it. The Sun’s heat and light provide the energy for life to exist on Earth. The Sun is a giant ball of extremely hot hydrogen and helium gases, nearly 150 million kilometres away. It is gigantic com ...
18th Cambridge Workshop on Cool Stars, Stellar Systems, and the... Proceedings of Lowell Observatory (9-13 June 2014)
18th Cambridge Workshop on Cool Stars, Stellar Systems, and the... Proceedings of Lowell Observatory (9-13 June 2014)

... topology (e.g., Reiners, 2012). Finally, with phase-resolved spectropolarimetric observations analysed by means of Zeeman-Doppler Imaging (ZDI) it is possible to reconstruct the intensity and topology of the large-scale component of stellar magnetic fields. But this technique tells us nothing about ...
Variation of Elements in Nature
Variation of Elements in Nature

... up as white dwarves. Old stars which formed when interstellar matter was poor in heavy elements will have their atmospheres consisting mainly of light elements. Later generation stars will show enhancement of heavy elements which can be seen from their spectral characteristics. The process of creati ...
Masers and high mass star formation Claire Chandler
Masers and high mass star formation Claire Chandler

... yet, but molecular gas available (a few of these cores are known) • Massive hot cores: Star has formed already, but accretion so strong that quenches ionization => no HII region (tens are known) • Ultracompact HII region: Accretion has ceased and detectable HII region exists (many are known) ...
Neutron stars and black holes
Neutron stars and black holes

... Since the Schwarzschild radius of a black hole is rSch = 2 GM / c2, the radius of a black hole is proportional to its mass. A one billion solar mass black hole will have a radius of 3 X 109 km. Since one Astronomical Unit ~ 1.5 X 108 km, it follows that a one billion solar mass black hole has a rad ...
Astronomy - Career Account Web Pages
Astronomy - Career Account Web Pages

... The most distant objects in the universe appear extremely red because their light is stretched to longer, redder wavelengths by the expansion of the universe. This object is at an extremely faint magnitude of 29, which is 500 million times fainter that the faintest stars seen by the human eye. The d ...
A Planetary Overview
A Planetary Overview

... occurs about once every 177 years. During this time the large outer planets Jupiter, Saturn, Uranus, and Neptune were bunched closely together looking out from Earth, as they traveled their orbits around the Sun. This had not happened since the time of Napoleon. Starting in 1972, NASA scientists and ...
Stars - Mike Brotherton
Stars - Mike Brotherton

... Same phenomenon makes the day sky appear blue (if it’s not cloudy). ...
L8 Condensation
L8 Condensation

... the inner regions of the nebula while volatile elements condense only at larger distance (outside the icelines). In order to compute which elements condense where, we assume that changes in temperature and density occur on a relatively long timescale compared to the chemical reaction timescale. This ...
Click here to the PowerPoint
Click here to the PowerPoint

... How is a supernova forms, and what happens inside it? Fusion stops, star collapses, explodes outwards. Elements heavier than iron are formed by fusion Compare black dwarves and neutron stars ...
Death of the Stars
Death of the Stars

... If the star’s mass is larger than 3 Msun, nothing can stop the collapse and the star shrinks… Force of Gravitation: FG = GmM / r2 On Earth, if we have to leave the planet we have to shoot a rocket up, and if the rocket can overcome this force it can escape from Earth. If shoot the rocket up with a s ...
The End of the World and Architecture
The End of the World and Architecture

... The Death of the Sun Our sun is classified as a yellow dwarf of medium size (864,000 miles in diameter) and of medium age (about 5 billion years old). The sun is a giant nuclear furnace that fuses hydrogen into helium at a temperature of 27 million degrees Fahrenheit and yields some 400 trillion wa ...
Round 2 - SAASTA
Round 2 - SAASTA

... Which of the following statements is incorrect about the Kuiper belt? A. It is found beyond Neptune B. It is where most dwarf planets are found C. It is found between Mars & Jupiter D. It surrounds our star, the Sun ...
Beyond Pluto
Beyond Pluto

... PLANETS lack a standard definition. If a body orbits a sun and was made spherical by its own gravity, astronomers tend to call it a planet. Yet that definition would include at least four asteroids and dozens of Kuiper belt objects. ASTEROIDS (a.k.a. minor planets) are rocky, metallic, or carbonaceo ...
Stars III - Indiana University Astronomy
Stars III - Indiana University Astronomy

... has occurred since the creation of the universe, only 2% of the ordinary matter in the universe is now in the form of heavy elements. Most is still hydrogen and helium ...
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Planetary habitability



Planetary habitability is the measure of a planet's or a natural satellite's potential to develop and sustain life. Life may develop directly on a planet or satellite or be transferred to it from another body, a theoretical process known as panspermia. As the existence of life beyond Earth is unknown, planetary habitability is largely an extrapolation of conditions on Earth and the characteristics of the Sun and Solar System which appear favourable to life's flourishing—in particular those factors that have sustained complex, multicellular organisms and not just simpler, unicellular creatures. Research and theory in this regard is a component of planetary science and the emerging discipline of astrobiology.An absolute requirement for life is an energy source, and the notion of planetary habitability implies that many other geophysical, geochemical, and astrophysical criteria must be met before an astronomical body can support life. In its astrobiology roadmap, NASA has defined the principal habitability criteria as ""extended regions of liquid water, conditions favourable for the assembly of complex organic molecules, and energy sources to sustain metabolism.""In determining the habitability potential of a body, studies focus on its bulk composition, orbital properties, atmosphere, and potential chemical interactions. Stellar characteristics of importance include mass and luminosity, stable variability, and high metallicity. Rocky, terrestrial-type planets and moons with the potential for Earth-like chemistry are a primary focus of astrobiological research, although more speculative habitability theories occasionally examine alternative biochemistries and other types of astronomical bodies.The idea that planets beyond Earth might host life is an ancient one, though historically it was framed by philosophy as much as physical science. The late 20th century saw two breakthroughs in the field. The observation and robotic spacecraft exploration of other planets and moons within the Solar System has provided critical information on defining habitability criteria and allowed for substantial geophysical comparisons between the Earth and other bodies. The discovery of extrasolar planets, beginning in the early 1990s and accelerating thereafter, has provided further information for the study of possible extraterrestrial life. These findings confirm that the Sun is not unique among stars in hosting planets and expands the habitability research horizon beyond the Solar System.The chemistry of life may have begun shortly after the Big Bang, 13.8 billion years ago, during a habitable epoch when the Universe was only 10–17 million years old. According to the panspermia hypothesis, microscopic life—distributed by meteoroids, asteroids and other small Solar System bodies—may exist throughout the universe. Nonetheless, Earth is the only place in the universe known to harbor life. Estimates of habitable zones around other stars, along with the discovery of hundreds of extrasolar planets and new insights into the extreme habitats here on Earth, suggest that there may be many more habitable places in the universe than considered possible until very recently. On 4 November 2013, astronomers reported, based on Kepler space mission data, that there could be as many as 40 billion Earth-sized planets orbiting in the habitable zones of Sun-like stars and red dwarfs within the Milky Way. 11 billion of these estimated planets may be orbiting Sun-like stars. The nearest such planet may be 12 light-years away, according to the scientists.
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