New Book by John Hogue:
Values not in the table can be calculated by using linear interpolation. Slum is stellar luminosity, it is the Lum column on the table. BC is bolometric correction, it is the Bolo. Steff is effective temperature, it is the Teeff column on the table.
These will be used in the equations below. This is important, since generally the only way a planet has oxygen in its atmosphere is by the action of native plant life.
This means that the primary star needs a lifetime longer than 3. This disqualifies stars with a spectral class of higher than F2. Obviously even though K0 stars has a lifespan of 1.
It is of type F7, which means it is hotter and whiter than Sol. Its mass is 1: The diameter is little greater, but spots, prominences, corona, and output of charged particles solar wind are fewer. It is a younger star than ours, though by less than a billion years. Either because of this, or because of variations in galactic distribution, the proportion of heavy elements in it and its planets is somewhat more than for the Solar System.
In earlier days, science fiction customarily put planets around the familiar ones like Sirius, Vega, Antares, or Mira. It was then legitimate enough, if a trifle repetitious. But today we know, or believe we know, that few of the naked-eye stars will serve.
Mostly they are giants, visible to us only because they are so brilliant that we can pick them out across immense gulfs of space. Sol would no longer be discernible without instruments at a distance of about 55 light-years.
Now the red giants like Antares, the variables like Mira, are dying stars, well on their way to the dim, ultra-dense white-dwarf condition. If ever they had planets—their mass makes that unlikely, as we will see in a minute—the inner attendants have been seared or even consumed, as these suns expanded.
Probably the majority of stars in the universe are still enjoying health. Their temperatures and luminosities vary enormously. The most important reason for this is the difference in their masses.
The more massive a sun is, the more intensely compressed it becomes at its core, and thus the more fierce and rapid are the thermonuclear reactions which cause it to shine. This dependence of output on mass is a highly sensitive one, so that the latter covers a much smaller range than the former.
These stars form a well-defined series, from the largest and brightest to the smallest and dimmest, which is called the main sequence. That last, G0, was formerly the classification of our own sun; but more recent information has gotten Sol to be labeled G2.
Figure 1 shows a large part of the main sequence. It omits the extremes, because they really are too extreme to diagram very well. That is, the main sequence runs from the hottest Type O blue giants, some as much as a million times the strength of Sol, on through the yellowish F and G stars, to the red dwarfs of Class M, the dimmest of which may be less than a thousandth as intense as our daystar.
Types are indicated along the bottom of the graph, with corresponding masses. Luminosities—necessarily on a logarithmic scale—are shown going up the left-hand side. From this, you can find the mass corresponding to a given brightness.
They vary by a fair amount, depending on such factors as the age and exact chemical composition of the individual star. More is involved than just the total radiation.
As everyone knows who has ever heated a piece of metal in a fire, temperature affects color. The hottest stars are called blue giants because they are not only giants in output, but also their light contains a distinctly larger proportion of blue than does that of Sol.
They also emit a higher percentage, as Well as absolute amount, of ultraviolet and X-ray wavelengths; and no doubt the solar winds streaming from them are something terrific.The first Satyagraha movements inspired by Mohandas Gandhi occurred in Champaran district of Bihar and the Kheda district of Gujarat on to ; Champaran Satyagraha was the first to be started, but the word Satyagraha was used for the first time in Anti Rowlatt Actagitation.
Champaran, is a district in the state of Bihar, tens of . Welcome to Insights IAS Revision Plan for UPSC Civil Services Preliminary Exam – If you are wondering why these questions are posted, please refer to the detailed Timetable provided HERE..
These questions serve TWO purposes: One to test your revision skills; Second is to give you a glimpse into topics that you might have missed . «Conversations with the “Jewish Messiah.” Introduction to a New Hogue Book. California Burnin’ up Climate Change.
RT first, Net Neutrality Next. Climate and Polar Maritime Air To what extent is the climate of the British Isles a product of the air masses that affect it?
Climate is defined as the weather averaged over a 30 year period, with weather being determined by temperature, humidity, wind and precipitation. The effects of these continental air masses are less prevalent than maritime influences; however they still have important influences on weather in the British Isles, and are also fundamental in explaining temporal and spatial differences in climate across the country.
An air mass that forms over the ocean near the equator and is A huge body of air that has similar temperature, humidity, and Cold dry air.
forms usually over northern Canada and Alaska.