PowerPoint Presentation - Research in observational
... Luminous Blue Variables • This is once again something to do with mass-loss. The most massive stars seem to go through unstable phases where not just the huge WR mass loss, but something altogether huger takes place. A real outburst (not a supernova) that loses many solar masses in a short time. • ...
... Luminous Blue Variables • This is once again something to do with mass-loss. The most massive stars seem to go through unstable phases where not just the huge WR mass loss, but something altogether huger takes place. A real outburst (not a supernova) that loses many solar masses in a short time. • ...
Measuring the Properties of Stars (ch. 17)
... masses of stars is from binary stars, using Newton’s form of Kepler’s 3rd law. There are three types of binary stars, which depend on how close they are to each other, their relative brightnesses, the distance of the binary, and other factors: a.Visual binaries—can see both stars, and so monitor orb ...
... masses of stars is from binary stars, using Newton’s form of Kepler’s 3rd law. There are three types of binary stars, which depend on how close they are to each other, their relative brightnesses, the distance of the binary, and other factors: a.Visual binaries—can see both stars, and so monitor orb ...
starevolution - Global Change Program
... masses of "Main Sequence" stars range from one-tenth of the Sun's mass at the lowest part, to some 50 or 100 solar masses at the upper end. Heavier stars burn up their fuel more quickly than the smaller stars. Happily for us, the Sun has been on the main sequence for around 4.5 billion years and wil ...
... masses of "Main Sequence" stars range from one-tenth of the Sun's mass at the lowest part, to some 50 or 100 solar masses at the upper end. Heavier stars burn up their fuel more quickly than the smaller stars. Happily for us, the Sun has been on the main sequence for around 4.5 billion years and wil ...
Stars III The Hertzsprung
... warm from the heat of gravitational contraction but are much fainter than stars • As such cooler objects have been found 2 ...
... warm from the heat of gravitational contraction but are much fainter than stars • As such cooler objects have been found 2 ...
luminosities
... The flux received from the light is proportional to its intrinsic brightness or luminosity (L) and inversely proportional to the square of the distance (d): ...
... The flux received from the light is proportional to its intrinsic brightness or luminosity (L) and inversely proportional to the square of the distance (d): ...
Lecture 12, PPT version
... The sun’s mass is 1.99x1030 kg, and at a current age of 4.5x109 years, we know that 70% of that mass is in hydrogen, or 1.39x1030 kg of hydrogen remains. If the sun converted ALL of it remaining hydrogen into helium (at today’s rate of “nuclear burning”), how much longer could the sun live? ...
... The sun’s mass is 1.99x1030 kg, and at a current age of 4.5x109 years, we know that 70% of that mass is in hydrogen, or 1.39x1030 kg of hydrogen remains. If the sun converted ALL of it remaining hydrogen into helium (at today’s rate of “nuclear burning”), how much longer could the sun live? ...
Unit 1
... A star’s location on the HR diagram is given by its temperature (x-axis) and luminosity (y-axis) We see that many stars are located on a diagonal line running from cool, dim stars to hot bright stars ...
... A star’s location on the HR diagram is given by its temperature (x-axis) and luminosity (y-axis) We see that many stars are located on a diagonal line running from cool, dim stars to hot bright stars ...
Ages of Star Clusters - Indiana University Astronomy
... Massive stars burn their nuclear fuel faster than lower mass stars and leave the main sequence sooner. In a cluster in which all the stars formed at the same time, the stars “peel off” the main sequence from the top, leaving only progressively less and less massive stars remaining on the main sequen ...
... Massive stars burn their nuclear fuel faster than lower mass stars and leave the main sequence sooner. In a cluster in which all the stars formed at the same time, the stars “peel off” the main sequence from the top, leaving only progressively less and less massive stars remaining on the main sequen ...
Main Sequence Stars
... given mass and chemical composition – if we start with a just formed protostar of a given mass and chemical composition, we can calculate how that star will evolve over its entire life. • This is extremely useful because it greatly simplifies the study of stars and is the basic reason why the HR dia ...
... given mass and chemical composition – if we start with a just formed protostar of a given mass and chemical composition, we can calculate how that star will evolve over its entire life. • This is extremely useful because it greatly simplifies the study of stars and is the basic reason why the HR dia ...
Chapter 13
... c. Some giants are between luminosity classes. d. Some giants are pulsating variable stars. e. Some giant stars have rapid rotation. ...
... c. Some giants are between luminosity classes. d. Some giants are pulsating variable stars. e. Some giant stars have rapid rotation. ...
Stars: Their Life and Afterlife
... not only tend to form close together in space, but also in time – and so, for massive stars, they will also die relatively close together in space and time. Superbubbles form from OB associations. OB associations are clusters of massive stars of spectral types – you guessed it – O and B. • O stars a ...
... not only tend to form close together in space, but also in time – and so, for massive stars, they will also die relatively close together in space and time. Superbubbles form from OB associations. OB associations are clusters of massive stars of spectral types – you guessed it – O and B. • O stars a ...
Slide 1
... the hydrogen lines are weak. Both HeI and HeII (singly ionized helium) are seen in the higher temperature examples. The radiation from O5 stars is so intense that it can ionize hydrogen over a volume of space 1000 light years across. One example is the luminous H II region surrounding star cluster M ...
... the hydrogen lines are weak. Both HeI and HeII (singly ionized helium) are seen in the higher temperature examples. The radiation from O5 stars is so intense that it can ionize hydrogen over a volume of space 1000 light years across. One example is the luminous H II region surrounding star cluster M ...
The Birth of Stars Guiding Questions • Because stars shine by
... 1. Why do astronomers think that stars evolve (bad use of term – this is about the birth, life and death of stars and that is NOT evolution)? 2. What kind of matter exists in the spaces between the stars? 3. In what kind of nebulae do new stars form? 4. What steps are involved in forming a star like ...
... 1. Why do astronomers think that stars evolve (bad use of term – this is about the birth, life and death of stars and that is NOT evolution)? 2. What kind of matter exists in the spaces between the stars? 3. In what kind of nebulae do new stars form? 4. What steps are involved in forming a star like ...
The Life of a Star - Department of Physics and Astronomy
... – Luminosity or brightness if ALL stars at 10pc ...
... – Luminosity or brightness if ALL stars at 10pc ...
The Temperature of Stars
... – The apparent motion of stars is the motion visible to the unaided eye. – Apparent motion is caused by the movement of Earth. – The rotation of Earth causes the apparent motion of stars sees as though the stars are moving counter-clockwise around the North Star. – Earth’s revolution around the sun ...
... – The apparent motion of stars is the motion visible to the unaided eye. – Apparent motion is caused by the movement of Earth. – The rotation of Earth causes the apparent motion of stars sees as though the stars are moving counter-clockwise around the North Star. – Earth’s revolution around the sun ...
PPT
... assigned over 100 years ago before temperatures were known. Had to be re-ordered to make sense. Still a useful aid to memory. ...
... assigned over 100 years ago before temperatures were known. Had to be re-ordered to make sense. Still a useful aid to memory. ...
formation2
... by gravity, it fragments into smaller pockets of gas which go on to form individual stars. • The result is a star cluster. The more massive pockets from massive stars, the less massive form smaller stars, like the Sun ...
... by gravity, it fragments into smaller pockets of gas which go on to form individual stars. • The result is a star cluster. The more massive pockets from massive stars, the less massive form smaller stars, like the Sun ...
17_LectureOutline
... Stellar spectra are much more informative than the blackbody curves. There are seven general categories of stellar spectra, corresponding to different ...
... Stellar spectra are much more informative than the blackbody curves. There are seven general categories of stellar spectra, corresponding to different ...
Slide 1
... Stellar spectra are much more informative than the blackbody curves. There are seven general categories of stellar spectra, corresponding to different ...
... Stellar spectra are much more informative than the blackbody curves. There are seven general categories of stellar spectra, corresponding to different ...
Spectral Classification: The First Step in Quantitative Spectral Analysis
... How are spectral types determined? They are determined via direct comparison with standard stars The spectral region/resolution are of secondary importance, as spectral classification is no longer confined to the classical blue-violet region of the spectrum. ...
... How are spectral types determined? They are determined via direct comparison with standard stars The spectral region/resolution are of secondary importance, as spectral classification is no longer confined to the classical blue-violet region of the spectrum. ...
PowerPoint Presentation - ASTR498E High energy
... We then define color indices by taking differences of the magnitudes measured in the different filters… U-B=mU-mB, B-V=mB-mV etc. Confused? Color index stellar temperature Question : Is B-V<0 a blue or red star, and what is the reference point? How does this change with distance? ...
... We then define color indices by taking differences of the magnitudes measured in the different filters… U-B=mU-mB, B-V=mB-mV etc. Confused? Color index stellar temperature Question : Is B-V<0 a blue or red star, and what is the reference point? How does this change with distance? ...
I CAN SEE THE STARS IN YOUR EYES
... at this speed, the trip from Earth to the sun, a distance of 93 million miles, would take about 8 minutes, not very long for such a long trip! Yet, to get to the next closest star, Proxima Centauri, would take 4.2 years. “Hmmm…,” you think to yourself, “that might be an interesting fact to include i ...
... at this speed, the trip from Earth to the sun, a distance of 93 million miles, would take about 8 minutes, not very long for such a long trip! Yet, to get to the next closest star, Proxima Centauri, would take 4.2 years. “Hmmm…,” you think to yourself, “that might be an interesting fact to include i ...
Stellar classification
In astronomy, stellar classification is the classification of stars based on their spectral characteristics. Light from the star is analyzed by splitting it with a prism or diffraction grating into a spectrum exhibiting the rainbow of colors interspersed with absorption lines. Each line indicates an ion of a certain chemical element, with the line strength indicating the abundance of that ion. The relative abundance of the different ions varies with the temperature of the photosphere. The spectral class of a star is a short code summarizing the ionization state, giving an objective measure of the photosphere's temperature and density.Most stars are currently classified under the Morgan–Keenan (MK) system using the letters O, B, A, F, G, K, and M, a sequence from the hottest (O type) to the coolest (M type). Each letter class is then subdivided using a numeric digit with 0 being hottest and 9 being coolest (e.g. A8, A9, F0, F1 form a sequence from hotter to cooler). The sequence has been expanded with classes for other stars and star-like objects that do not fit in the classical system, such class D for white dwarfs and class C for carbon stars.In the MK system a luminosity class is added to the spectral class using Roman numerals. This is based on the width of certain absorption lines in the star's spectrum which vary with the density of the atmosphere and so distinguish giant stars from dwarfs. Luminosity class 0 or Ia+ stars for hypergiants, class I stars for supergiants, class II for bright giants, class III for regular giants, class IV for sub-giants, class V for main-sequence stars, class sd for sub-dwarfs, and class D for white dwarfs. The full spectral class for the Sun is then G2V, indicating a main-sequence star with a temperature around 5,800K.