a to z of astronomy
... the equator and ecliptic intersect. The vernal equinox occurs on or around March 21 each year and the autumnal equinox on or about September 21. The position in the sky of the vernal equinox is also known as the first point of Aries, and is the zero point for right ascension measurements. Despite it ...
... the equator and ecliptic intersect. The vernal equinox occurs on or around March 21 each year and the autumnal equinox on or about September 21. The position in the sky of the vernal equinox is also known as the first point of Aries, and is the zero point for right ascension measurements. Despite it ...
Brightness and Distance
... steradian (a unit of solid angle). It is important to note that luminous intensity takes into account the response of the human visual system. In other words, our eyes are not equally sensitive to all wavelengths of visible light. Since the response of the human eye to brightness is close to logarit ...
... steradian (a unit of solid angle). It is important to note that luminous intensity takes into account the response of the human visual system. In other words, our eyes are not equally sensitive to all wavelengths of visible light. Since the response of the human eye to brightness is close to logarit ...
VLT/FORS Surveys of Wolf-Rayet Stars beyond the
... RSGs, known as the Humphreys-Davidson limit, such that initially more massive stars circumvent the RSG phase, pass through a Luminous Blue Variable stage, before ending their life as Wolf-Rayet (WR) stars, exhibiting either the products of core-H burning (WN subtypes) or sub sequent core-He burning ...
... RSGs, known as the Humphreys-Davidson limit, such that initially more massive stars circumvent the RSG phase, pass through a Luminous Blue Variable stage, before ending their life as Wolf-Rayet (WR) stars, exhibiting either the products of core-H burning (WN subtypes) or sub sequent core-He burning ...
March 2016 BRAS Addendum Newsletter
... Sirius (Alpha CMa), “scorching”, “the Dog Star”, mag. -1.46, 06 45 09.25 -16 42 47.3, is a blue-white binary star, and is also the brightest star in the night sky. The companion star, Sirius B (the Pup),is a white dwarf star with a magnitude of 8.4, and has an orbital period of 50 years and a separa ...
... Sirius (Alpha CMa), “scorching”, “the Dog Star”, mag. -1.46, 06 45 09.25 -16 42 47.3, is a blue-white binary star, and is also the brightest star in the night sky. The companion star, Sirius B (the Pup),is a white dwarf star with a magnitude of 8.4, and has an orbital period of 50 years and a separa ...
Lecture19
... As material is sucked down onto a black hole (from a mass losing binary companion, for instance), it emits strong X-rays. Objects can happily orbit a black hole; only when they get close are they in trouble. It does not “suck everything around it in”. Binary orbits give you an estimate of the mass o ...
... As material is sucked down onto a black hole (from a mass losing binary companion, for instance), it emits strong X-rays. Objects can happily orbit a black hole; only when they get close are they in trouble. It does not “suck everything around it in”. Binary orbits give you an estimate of the mass o ...
Fulltext PDF - Indian Academy of Sciences
... our line of sight. Only when the two components are gravitationally bound to each other, can they be called binaries. The two components are resolved in a telescope and one can measure ...
... our line of sight. Only when the two components are gravitationally bound to each other, can they be called binaries. The two components are resolved in a telescope and one can measure ...
chapter16StarBirth
... Mass of a Star-Forming Cloud • A typical molecular cloud (T~ 30 K, n ~ 300 particles/cm3) must contain at least a few hundred solar masses for gravity to overcome pressure • Emission lines from molecules in a cloud can prevent a pressure buildup by converting thermal energy into infrared and radio ...
... Mass of a Star-Forming Cloud • A typical molecular cloud (T~ 30 K, n ~ 300 particles/cm3) must contain at least a few hundred solar masses for gravity to overcome pressure • Emission lines from molecules in a cloud can prevent a pressure buildup by converting thermal energy into infrared and radio ...
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 ...
... 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 ...
Lect15-3-23-11-stars..
... d motion, which has an associated kinetic energy derived from the liberation of gravitational potential energy. We can also think of the inward moving material as colliding with other material moving inward and toward it, so that the kinetic energy of the ordered motion is transformed into kinetic e ...
... d motion, which has an associated kinetic energy derived from the liberation of gravitational potential energy. We can also think of the inward moving material as colliding with other material moving inward and toward it, so that the kinetic energy of the ordered motion is transformed into kinetic e ...
Spectroscopy – the study of the colors of light (the spectrum) given
... intense lines of singly-ionized helium and multiply-ionized heavier elements (O, N, Si). There are no Hydrogen lines because the hydrogen is mostly ionized, so no lines due to excited electrons. ...
... intense lines of singly-ionized helium and multiply-ionized heavier elements (O, N, Si). There are no Hydrogen lines because the hydrogen is mostly ionized, so no lines due to excited electrons. ...
An introduce of the spectrograph of the GALEX
... distribution of the sources detected by our survey peaks at around z=0.6-1.0 (the location of the peak being affected by cosmic variance) and decays monotonically from z~1 to z~3. (...) The cosmic star formation rate (SFR) density goes as (1+z)4.0+/-0.2 from z=0 to 0.8. From z=0.8 to z~1.2, the SFR ...
... distribution of the sources detected by our survey peaks at around z=0.6-1.0 (the location of the peak being affected by cosmic variance) and decays monotonically from z~1 to z~3. (...) The cosmic star formation rate (SFR) density goes as (1+z)4.0+/-0.2 from z=0 to 0.8. From z=0.8 to z~1.2, the SFR ...
CHAPTER 14
... (b) Type II: their spectrum contains prominent hydrogen lines; they originate from the explosion of a single star. 5. Type I supernovae are divided into three subclasses: (a) Type Ib, and Ic are caused by massive stars that have lost different proportions of their outer layers before exploding. (b) ...
... (b) Type II: their spectrum contains prominent hydrogen lines; they originate from the explosion of a single star. 5. Type I supernovae are divided into three subclasses: (a) Type Ib, and Ic are caused by massive stars that have lost different proportions of their outer layers before exploding. (b) ...
Distance to the SMC
... Walter Baade, using the newly built Palomar 200 inch telescope, discovered that stars can be classified into two general age categories. Population I stars are relatively young and formed after the interstellar medium was enriched with metals from the explosions of supernova and the deaths of other ...
... Walter Baade, using the newly built Palomar 200 inch telescope, discovered that stars can be classified into two general age categories. Population I stars are relatively young and formed after the interstellar medium was enriched with metals from the explosions of supernova and the deaths of other ...
PH607lec11-4gal2
... Early type spirals formed most of their stars early on (used up their gas, have older/redder stars) ...
... Early type spirals formed most of their stars early on (used up their gas, have older/redder stars) ...
Sakurai`s Object - Department of Physics, HKU
... circular planetary nebula around the central star V4334 SGR. • At this point, it is clear that Sakurai has discovered an object undergoing a final helium flash. • And for the first time, this object is referred to as the Sakurai’s Object (櫻井天體). ...
... circular planetary nebula around the central star V4334 SGR. • At this point, it is clear that Sakurai has discovered an object undergoing a final helium flash. • And for the first time, this object is referred to as the Sakurai’s Object (櫻井天體). ...
Part 2 of Our Lecture
... WTTS (green) CTTS (red) HD 206267 (blue) in Tr37 High- and intermediate-mass stars (open stars) ...
... WTTS (green) CTTS (red) HD 206267 (blue) in Tr37 High- and intermediate-mass stars (open stars) ...
The Magnitude Scale
... where Fν is the flux per unit frequency received from the source, and F ν0 is a normalising constant. The normalising constants have been calibrated for standard photometric bands, some of which are listed in table 1 below. Notice that a larger value of the magnitude means that the source is fainter ...
... where Fν is the flux per unit frequency received from the source, and F ν0 is a normalising constant. The normalising constants have been calibrated for standard photometric bands, some of which are listed in table 1 below. Notice that a larger value of the magnitude means that the source is fainter ...
Document
... • Can we see through our galaxy’s interstellar medium? • The gas and dust that make up the interstellar medium absorb visible light, preventing us from seeing most of the galaxy’s disk in these wavelengths. However, some other wavelengths of light, notably infrared and radio, can pass through the ga ...
... • Can we see through our galaxy’s interstellar medium? • The gas and dust that make up the interstellar medium absorb visible light, preventing us from seeing most of the galaxy’s disk in these wavelengths. However, some other wavelengths of light, notably infrared and radio, can pass through the ga ...
Photoelectric Photometry of the Pleiades
... star and make measurements. Different filters can be selected for each observation, and the integration time (the length of time the photometer samples the starlight) is adjustable. The computer also does much of the busy work needed to convert photon counts into apparent magnitude and provides an e ...
... star and make measurements. Different filters can be selected for each observation, and the integration time (the length of time the photometer samples the starlight) is adjustable. The computer also does much of the busy work needed to convert photon counts into apparent magnitude and provides an e ...
chapter16StarBirth
... • Without CO molecules to provide cooling, the clouds that formed the first stars had to be considerably warmer than today’s molecular clouds • The first stars must therefore have been more massive than most of today’s stars, for gravity to overcome pressure ...
... • Without CO molecules to provide cooling, the clouds that formed the first stars had to be considerably warmer than today’s molecular clouds • The first stars must therefore have been more massive than most of today’s stars, for gravity to overcome pressure ...
What are Messier Objects? - Bowling Green State University
... cluster in Orion. Also known as the Orion Nebula. Is one of the brightest starforming nebulae and one of the brightest diffusion nebulae in the sky It is a big object, considered to cover four times the area of the full moon. Located 1,600 light years away. Is a very turbulent cloud of gas ...
... cluster in Orion. Also known as the Orion Nebula. Is one of the brightest starforming nebulae and one of the brightest diffusion nebulae in the sky It is a big object, considered to cover four times the area of the full moon. Located 1,600 light years away. Is a very turbulent cloud of gas ...
stars and beyond - Math/Science Nucleus
... Comets may be leftovers from the formation of the Solar System. An asteroid is a mass of rock and minor amounts of frozen gas. Like comets, asteroids are probably leftovers from forming the planets. Most asteroids are in orbits between Mars and Jupiter. They range in size from dust specks to over 30 ...
... Comets may be leftovers from the formation of the Solar System. An asteroid is a mass of rock and minor amounts of frozen gas. Like comets, asteroids are probably leftovers from forming the planets. Most asteroids are in orbits between Mars and Jupiter. They range in size from dust specks to over 30 ...
Life Cycle of a Star Vocabulary
... nuclear fuel, some of its mass flows into its core. • Core becomes so heavy that it cannot withstand its own ...
... nuclear fuel, some of its mass flows into its core. • Core becomes so heavy that it cannot withstand its own ...
MS Word version
... that a complete parallel of declination is made for the star. Now drag this active star so that it is at the north point of the horizon. (Make sure the star is active so you can read off its coordinates.) Note that a star with a slightly smaller declination would dip below the north point while a st ...
... that a complete parallel of declination is made for the star. Now drag this active star so that it is at the north point of the horizon. (Make sure the star is active so you can read off its coordinates.) Note that a star with a slightly smaller declination would dip below the north point while a st ...
Serpens
Serpens (""the Serpent"", Greek Ὄφις) is a constellation of the northern hemisphere. One of the 48 constellations listed by the 2nd-century astronomer Ptolemy, it remains one of the 88 modern constellations defined by the International Astronomical Union. It is unique among the modern constellations in being split into two non-contiguous parts, Serpens Caput (Serpent's Head) to the west and Serpens Cauda (Serpent's Tail) to the east. Between these two halves lies the constellation of Ophiuchus, the ""Serpent-Bearer"". In figurative representations, the body of the serpent is represented as passing behind Ophiuchus between Mu Serpentis in Serpens Caput and Nu Serpentis in Serpens Cauda.The brightest star in Serpens is the red giant star Alpha Serpentis, or Unukalhai, in Serpens Caput, with an apparent magnitude of 2.63. Also located in Serpens Caput are the naked-eye globular cluster Messier 5 and the naked-eye variables R Serpentis and Tau4 Serpentis. Notable extragalactic objects include Seyfert's Sextet, one of the densest galaxy clusters known; Arp 220, the prototypical ultraluminous infrared galaxy; and Hoag's Object, the most famous of the very rare class of galaxies known as ring galaxies.Part of the Milky Way's galactic plane passes through Serpens Cauda, which is therefore rich in galactic deep-sky objects, such as the Eagle Nebula (IC 4703) and its associated star cluster Messier 16. The nebula measures 70 light-years by 50 light-years and contains the Pillars of Creation, three dust clouds that became famous for the image taken by the Hubble Space Telescope. Other striking objects include the Red Square Nebula, one of the few objects in astronomy to take on a square shape; and Westerhout 40, a massive nearby star-forming region consisting of a molecular cloud and an H II region.