DoAr21_AAS2005 - Astronomy at Swarthmore College
... emission reported subsequently and without a strong IR excess. It is only about 1 Myr old (left) and has already been identified, via lowresolution x-ray spectroscopy, to have strong, hard, and variable x-ray emission (Imanishi et al. 2002). One of the few PMS stars that is x-ray bright enough to pr ...
... emission reported subsequently and without a strong IR excess. It is only about 1 Myr old (left) and has already been identified, via lowresolution x-ray spectroscopy, to have strong, hard, and variable x-ray emission (Imanishi et al. 2002). One of the few PMS stars that is x-ray bright enough to pr ...
Family of stars - Inside Mines
... surface composition was very similar to what is observed on Earth. • In 1925, Cecilia Payne suggests in her PhD that the intensity of the lines is not simply proportional to the abundance of those elements. • The surface temperature also defines which lines are strongly (or weakly) expressed. Once t ...
... surface composition was very similar to what is observed on Earth. • In 1925, Cecilia Payne suggests in her PhD that the intensity of the lines is not simply proportional to the abundance of those elements. • The surface temperature also defines which lines are strongly (or weakly) expressed. Once t ...
AST1100 Lecture Notes
... We have so far seen temperature on the x-axis. The temperature of a star is directly related to its color and one can therefore also use the B − V color index (see the lecture on cosmic distances) on the x-axis. There is also another another possibility: spectral classes. Stars are classified accord ...
... We have so far seen temperature on the x-axis. The temperature of a star is directly related to its color and one can therefore also use the B − V color index (see the lecture on cosmic distances) on the x-axis. There is also another another possibility: spectral classes. Stars are classified accord ...
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... Annie Jump Cannon – worked with Pickering at Harvard College Observatory, did most of the classifications for the Henry Draper Catalog, her job title was “computer”. Henrietta Leavitt – worked as an assistant to Baade at the Mount Wilson Observatory. In 1912 she discovered the period – luminosity la ...
... Annie Jump Cannon – worked with Pickering at Harvard College Observatory, did most of the classifications for the Henry Draper Catalog, her job title was “computer”. Henrietta Leavitt – worked as an assistant to Baade at the Mount Wilson Observatory. In 1912 she discovered the period – luminosity la ...
Chapter 6: Stellar Evolution (part 2)
... Neutron stars as pulsars A newly born neutron star is expected to have fast rotation and strong magnetic field. Such magnetized and fast rotating neutron stars explain the presence of pulsars. The life time of a pulsar is typically on the order of 107 years, depending on the magnetic field, which d ...
... Neutron stars as pulsars A newly born neutron star is expected to have fast rotation and strong magnetic field. Such magnetized and fast rotating neutron stars explain the presence of pulsars. The life time of a pulsar is typically on the order of 107 years, depending on the magnetic field, which d ...
Exam #2 Solutions
... the point on an HR diagram where conditions within the core of the star are sufficient to initiate fusion. ZAMS is an acronym for Zero Age Main Sequence. B. The five stars that appear in nearly a straight line in the lower left of the HR diagram are what type of objects? These five objects are white ...
... the point on an HR diagram where conditions within the core of the star are sufficient to initiate fusion. ZAMS is an acronym for Zero Age Main Sequence. B. The five stars that appear in nearly a straight line in the lower left of the HR diagram are what type of objects? These five objects are white ...
Announcements - Lick Observatory
... stars in many of the evolutionary phases. Can test timescale, surface temperature and luminosity predictions. After 30 years of testing, it looks like we understand the basic evolution of stars very well. (2) My personal favorite test is the measurement of radioactive Tc in AGB stars. ...
... stars in many of the evolutionary phases. Can test timescale, surface temperature and luminosity predictions. After 30 years of testing, it looks like we understand the basic evolution of stars very well. (2) My personal favorite test is the measurement of radioactive Tc in AGB stars. ...
An Overview of the Gaia
... • Hard to get very high-quality spectra (<2-3%). Need space observations to access the UV • Great progress in the last decade (Bohlin+ Cohen+) • HST flux calibration based on Oke V scale plus hot DA WD models. Consistency all around with Vega and solar analogs. Solar analogs observed With STIS compa ...
... • Hard to get very high-quality spectra (<2-3%). Need space observations to access the UV • Great progress in the last decade (Bohlin+ Cohen+) • HST flux calibration based on Oke V scale plus hot DA WD models. Consistency all around with Vega and solar analogs. Solar analogs observed With STIS compa ...
The surface composition of Beta Pictoris
... listed in Tab. 1. Figure 1 illustrates the case of Cr II; error limits shown are estimates based on the fit of observed and synthetic spectrum. Ti II and Fe II look similar, but the spread is somewhat larger. We suppose that the Cr II gf -values have the highest internal accuracy. The slight residua ...
... listed in Tab. 1. Figure 1 illustrates the case of Cr II; error limits shown are estimates based on the fit of observed and synthetic spectrum. Ti II and Fe II look similar, but the spread is somewhat larger. We suppose that the Cr II gf -values have the highest internal accuracy. The slight residua ...
12.1 Introduction
... The requirement of course is that they must match the data, in this case provided by the H-R diagrams of clusters, where all the stars are assumed to ...
... The requirement of course is that they must match the data, in this case provided by the H-R diagrams of clusters, where all the stars are assumed to ...
The Interstellar Medium
... absorbed by interstellar clouds. Red light can more easily penetrate the cloud, but is still absorbed to some extent. ...
... absorbed by interstellar clouds. Red light can more easily penetrate the cloud, but is still absorbed to some extent. ...
The Interstellar Medium
... absorbed by interstellar clouds. Red light can more easily penetrate the cloud, but is still absorbed to some extent. ...
... absorbed by interstellar clouds. Red light can more easily penetrate the cloud, but is still absorbed to some extent. ...
Lecture 9
... As the helium core grows, it compresses. Helium doesn’t fuse to heavier elements for two reasons. (1) with 2 p+ per nucleus, the electric repulsion force is higher than was the case for H-fusion. This means that helium fusion requires a higher temperature than hydrogen fusion -- 100 million K ( ...
... As the helium core grows, it compresses. Helium doesn’t fuse to heavier elements for two reasons. (1) with 2 p+ per nucleus, the electric repulsion force is higher than was the case for H-fusion. This means that helium fusion requires a higher temperature than hydrogen fusion -- 100 million K ( ...
Stellar Evolution in the HR Diagram
... Thermal Pulse Asymptotic Giant Branch Stars • During the AGB phase, large amount of dust are created in the star’s atmosphere. This dust gets ejected into space during the TPAGB phase and can enshroud the star (at least in the optical). As a result, TP-AGB stars can be extremely bright in the near ...
... Thermal Pulse Asymptotic Giant Branch Stars • During the AGB phase, large amount of dust are created in the star’s atmosphere. This dust gets ejected into space during the TPAGB phase and can enshroud the star (at least in the optical). As a result, TP-AGB stars can be extremely bright in the near ...
A Digital Spectral Classification Atlas
... blue-violet part of the spectrum. This was done by necessity, as scientific photographic emulsions in the 1940’s were sensitive only to blue-violet light. However, it was a fortunate choice, as the blue-violet portion of the spectrum (essentially from the Ca II K-line to Hβ ) contains a high density ...
... blue-violet part of the spectrum. This was done by necessity, as scientific photographic emulsions in the 1940’s were sensitive only to blue-violet light. However, it was a fortunate choice, as the blue-violet portion of the spectrum (essentially from the Ca II K-line to Hβ ) contains a high density ...
Solutions
... 13. Are all red giants or supergiants very massive stars? Why are red giants so big and red? What is going on inside the giants? All red giants or supergiants are NOT very massive stars. In fact, our own Sun will become a red giant and a red supergiant as it evolves through its final sequence of ene ...
... 13. Are all red giants or supergiants very massive stars? Why are red giants so big and red? What is going on inside the giants? All red giants or supergiants are NOT very massive stars. In fact, our own Sun will become a red giant and a red supergiant as it evolves through its final sequence of ene ...
Chapter 20
... The regions of gas and dust (often called clouds, or “giant molecular clouds”) from which stars are forming are best observed in the infrared and radio regions of the spectrum, because most other forms of radiation (such as optical and ultraviolet) cannot penetrate them. ...
... The regions of gas and dust (often called clouds, or “giant molecular clouds”) from which stars are forming are best observed in the infrared and radio regions of the spectrum, because most other forms of radiation (such as optical and ultraviolet) cannot penetrate them. ...
Review Sheet and Study Hints - Tufts Institute of Cosmology
... How to go from the Milky Way in the sky to an image of our Galaxy Counting stars, determining distances; Kaptyn’s Universe; Shapley-Curits Debate --the size and shape of the universe Resolution of debate – both scientists were right and wrong Observing the Milky way at different wavelength ...
... How to go from the Milky Way in the sky to an image of our Galaxy Counting stars, determining distances; Kaptyn’s Universe; Shapley-Curits Debate --the size and shape of the universe Resolution of debate – both scientists were right and wrong Observing the Milky way at different wavelength ...
1. setting the scene 2. the cosmic dark ages and the first stars
... associated with galaxies. In the spectrum of a given quasar there are normally many sets of absorption lines, or ‘absorption systems’. Each absorption system is at a different distance along the path travelled by the quasar light on its way to our telescopes on Earth, and therefore appears at a diff ...
... associated with galaxies. In the spectrum of a given quasar there are normally many sets of absorption lines, or ‘absorption systems’. Each absorption system is at a different distance along the path travelled by the quasar light on its way to our telescopes on Earth, and therefore appears at a diff ...
L87 THE b PICTORIS MOVING GROUP B. ZUCkERMAN AND
... The velocity range, ≤"2 km s!1, displayed by Table 1 stars is characteristic of velocity dispersions measured in star-forming interstellar molecular clouds. Thus, plausibly, the b Pic group formed in such a cloud or cloud complex. Some of the velocity dispersion apparent in UVW may be due to measure ...
... The velocity range, ≤"2 km s!1, displayed by Table 1 stars is characteristic of velocity dispersions measured in star-forming interstellar molecular clouds. Thus, plausibly, the b Pic group formed in such a cloud or cloud complex. Some of the velocity dispersion apparent in UVW may be due to measure ...
Variable Star Spectroscopy 2008
... In the picture you can see the ATIK 16IC imaging camera (lower left) the Stellacam guide camera (upper left) and on the right, the micrometer adjustment to adjust the grating angle to select the required wavelength range. On the front is a switch for the built in neon calibration lamp. (The black bo ...
... In the picture you can see the ATIK 16IC imaging camera (lower left) the Stellacam guide camera (upper left) and on the right, the micrometer adjustment to adjust the grating angle to select the required wavelength range. On the front is a switch for the built in neon calibration lamp. (The black bo ...
Colors of Stars: Teacher Lesson Plan
... projector. Each group may refer to these images, as well as their drawings, to describe their flame. In stars, just as in Earth-bound fires, blue is hotter than yellow, and yellow is hotter than red. The Sun is much hotter than a candle flame. Unlike a candle, the Sun uses nuclear fusion as its ener ...
... projector. Each group may refer to these images, as well as their drawings, to describe their flame. In stars, just as in Earth-bound fires, blue is hotter than yellow, and yellow is hotter than red. The Sun is much hotter than a candle flame. Unlike a candle, the Sun uses nuclear fusion as its ener ...
Color and Temperature of Stars
... If you look carefully at the stars, even without binoculars or a telescope, you will see a range of color from reddish to yellowish to bluish. For example, Betelgeuse looks reddish, Pollux -- like the sun -- is yellowish, and Rigel looks bluish. A star's color depends on its surface temperature. Ast ...
... If you look carefully at the stars, even without binoculars or a telescope, you will see a range of color from reddish to yellowish to bluish. For example, Betelgeuse looks reddish, Pollux -- like the sun -- is yellowish, and Rigel looks bluish. A star's color depends on its surface temperature. Ast ...
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.