Observational properties of stars
... spectrum, “B” corresponds to blue light, “V” is green, “R” is red and “I” is infrared. There are actually hundreds of different types of filters, some are telescope specific, or are used only by particular observatories. However, the filters given here are the most commonly used in stellar astronomy ...
... spectrum, “B” corresponds to blue light, “V” is green, “R” is red and “I” is infrared. There are actually hundreds of different types of filters, some are telescope specific, or are used only by particular observatories. However, the filters given here are the most commonly used in stellar astronomy ...
Chemical Composition and Evolutionary Status of the Ap Star HD
... chemically peculiar Ap stars. It was first classified in the catalog by Renson and Manfroid (2009) as Sr– Cr–Eu of type F0. HD 138633 fell into in the list for pulsation observations based on its Strömgren photometric indices (the 072.D-0138(A) program of observations on the 8-m VLT telescope), but n ...
... chemically peculiar Ap stars. It was first classified in the catalog by Renson and Manfroid (2009) as Sr– Cr–Eu of type F0. HD 138633 fell into in the list for pulsation observations based on its Strömgren photometric indices (the 072.D-0138(A) program of observations on the 8-m VLT telescope), but n ...
White Dwarf Stars - Stellar Physics Department
... their spectral classification. This index is defined as θ = 50400/Teff . Therefore, a white dwarf showing Balmer lines with an effective temperature of 20 000 K will be classified DA2.5. The temperature index is not always provided. The temperature of white dwarfs ranges from ∼ 100 000 K down to abo ...
... their spectral classification. This index is defined as θ = 50400/Teff . Therefore, a white dwarf showing Balmer lines with an effective temperature of 20 000 K will be classified DA2.5. The temperature index is not always provided. The temperature of white dwarfs ranges from ∼ 100 000 K down to abo ...
We Are Made of Stardust
... atoms begin to fuse into sodium (Na), magnesium (Mg), aluminum (Al), and silicon (Si). After a threshold of silicon has been reached, the silicon atoms begin fusing with helium into phosphorus (P), sulfur (S), chlorine (Cl), Potassium (K), Calcium (Ca), and Manganese (25). Note: This is a bit of a ...
... atoms begin to fuse into sodium (Na), magnesium (Mg), aluminum (Al), and silicon (Si). After a threshold of silicon has been reached, the silicon atoms begin fusing with helium into phosphorus (P), sulfur (S), chlorine (Cl), Potassium (K), Calcium (Ca), and Manganese (25). Note: This is a bit of a ...
Discovery of White Dwarfs—8 Oct
... Hertzsprung-Russell Diagram of nearby stars 1. Stars in region X are A. Dwarfs B. Giants C. White dwarfs ...
... Hertzsprung-Russell Diagram of nearby stars 1. Stars in region X are A. Dwarfs B. Giants C. White dwarfs ...
X-rays - Astronomy at Swarthmore College
... X-rays from the Sun Remember - for thermal radiation - the frequency of light (the energy of each photon) is proportional to the temperature of the emitter: Human body = 300 K 10 microns, or 100,000 Å (infrared) Sun, light bulb filament = 6000 K 5000 Å (visible, yellow) Hot star’s surface = 40, ...
... X-rays from the Sun Remember - for thermal radiation - the frequency of light (the energy of each photon) is proportional to the temperature of the emitter: Human body = 300 K 10 microns, or 100,000 Å (infrared) Sun, light bulb filament = 6000 K 5000 Å (visible, yellow) Hot star’s surface = 40, ...
Chapter 7 Formation of Stars
... stars near the Orion Nebula. In the top image, the star responsible for the jets is hidden in the dark dust cloud lying in the center of the image. The entire width of this image is about one light year. The Herbig–Haro objects are designated HH-1 and HH-2, and correspond to the nebulosity at the en ...
... stars near the Orion Nebula. In the top image, the star responsible for the jets is hidden in the dark dust cloud lying in the center of the image. The entire width of this image is about one light year. The Herbig–Haro objects are designated HH-1 and HH-2, and correspond to the nebulosity at the en ...
Chapter 8 Formation of Stars
... stars near the Orion Nebula. In the top image, the star responsible for the jets is hidden in the dark dust cloud lying in the center of the image. The entire width of this image is about one light year. The Herbig–Haro objects are designated HH-1 and HH-2, and correspond to the nebulosity at the en ...
... stars near the Orion Nebula. In the top image, the star responsible for the jets is hidden in the dark dust cloud lying in the center of the image. The entire width of this image is about one light year. The Herbig–Haro objects are designated HH-1 and HH-2, and correspond to the nebulosity at the en ...
structure and evolution of white dwarfs and their
... signatures of only hydrogen and, possibly, helium. White dwarfs are thus divided into two main groups according to whether or not their spectra are dominated by one or other of these elements. The hydrogen-rich stars are given the classification DA, while the helium-rich white dwarfs are designated ...
... signatures of only hydrogen and, possibly, helium. White dwarfs are thus divided into two main groups according to whether or not their spectra are dominated by one or other of these elements. The hydrogen-rich stars are given the classification DA, while the helium-rich white dwarfs are designated ...
Document
... Only 10-40% of the gas goes into stars. Stellar winds, jets and supernova explosions blow away the gas from the cluster and stop any further star ...
... Only 10-40% of the gas goes into stars. Stellar winds, jets and supernova explosions blow away the gas from the cluster and stop any further star ...
30 Doradus - HubbleSOURCE
... Only 10-40% of the gas goes into stars. Stellar winds, jets and supernova explosions blow away the gas from the cluster and stop any further star ...
... Only 10-40% of the gas goes into stars. Stellar winds, jets and supernova explosions blow away the gas from the cluster and stop any further star ...
Astrophysics Pristine CNO abundances from Magellanic Cloud B stars
... Large Magellanic Cloud (LMC). Apart from H ii regions, unevolved OB-type stars are currently the only accessible source of present-day CNO abundances for the MCs not altered by stellar evolution. Using UVES on the VLT, we obtained spectra of sufficient resolution (R = 20 000) and signal-to-noise (S/ ...
... Large Magellanic Cloud (LMC). Apart from H ii regions, unevolved OB-type stars are currently the only accessible source of present-day CNO abundances for the MCs not altered by stellar evolution. Using UVES on the VLT, we obtained spectra of sufficient resolution (R = 20 000) and signal-to-noise (S/ ...
Evolution of a Planetary System
... 1. Review. Remind the students that in the last Mission, they learned how planets may form around a star. But are all stars the same? Now we will study how stars can vary in their color and temperature. Star types were first invented to identify stars with different colors. For example, our Sun is a ...
... 1. Review. Remind the students that in the last Mission, they learned how planets may form around a star. But are all stars the same? Now we will study how stars can vary in their color and temperature. Star types were first invented to identify stars with different colors. For example, our Sun is a ...
CHP 11
... 1. Protostars are difficult to observe because a. the protostar stage is very short. b. they are surrounded by cocoons of gas and dust. c. they radiate mainly in the infrared. d. all of the above e. they are all so far away that the light hasn't reached us yet. 2. The nuclear reactions in a star's c ...
... 1. Protostars are difficult to observe because a. the protostar stage is very short. b. they are surrounded by cocoons of gas and dust. c. they radiate mainly in the infrared. d. all of the above e. they are all so far away that the light hasn't reached us yet. 2. The nuclear reactions in a star's c ...
ppt - Institute for Astronomy
... Given the rarity of FUors, this would be extremely unlikely if the events were not related, i.e., whatever triggered the eruption in one should be connected to what triggered the eruption in the ...
... Given the rarity of FUors, this would be extremely unlikely if the events were not related, i.e., whatever triggered the eruption in one should be connected to what triggered the eruption in the ...
Gaps
... The spectroscopic approach POSSIBLE INTERPRETATIONS • Why some blue HB stars are spinning so fast? 1) Angular momentum transferred from the core to the outer envelope: Magnetic braking on MS only affects a star’s envelope (Peterson et al. 1983, Pinsonneault et al. 1991) Problems : Sun (Corbard et a ...
... The spectroscopic approach POSSIBLE INTERPRETATIONS • Why some blue HB stars are spinning so fast? 1) Angular momentum transferred from the core to the outer envelope: Magnetic braking on MS only affects a star’s envelope (Peterson et al. 1983, Pinsonneault et al. 1991) Problems : Sun (Corbard et a ...
Powerpoint Review
... Once white dwarfs have all burnt out, it is thought that they will form a black dwarf. At this point there are not black dwarfs found in our universe. The reason for this is our universe is not old enough and there has not been a white dwarf that has burn out yet. At some point in the future, a wh ...
... Once white dwarfs have all burnt out, it is thought that they will form a black dwarf. At this point there are not black dwarfs found in our universe. The reason for this is our universe is not old enough and there has not been a white dwarf that has burn out yet. At some point in the future, a wh ...
17_LectureOutline
... In order to measure stellar masses in a binary star, the period and semimajor axis of the orbit must be measured. Once this is done, Kepler’s third law gives the sum of the masses of the two stars. Then the relative speeds of the two stars can be measured using the Doppler effect; the speed will be ...
... In order to measure stellar masses in a binary star, the period and semimajor axis of the orbit must be measured. Once this is done, Kepler’s third law gives the sum of the masses of the two stars. Then the relative speeds of the two stars can be measured using the Doppler effect; the speed will be ...
13.1 Introduction 13.2 The Red Giant Branch
... the same for all stellar masses. However, the conditions in the core at the ignition of helium are very different in low-mass stars (which have degenerate cores) from stars of higher mass (with non-degenerate cores). The electrons in the core of a 1M star are completely degenerate by the time the s ...
... the same for all stellar masses. However, the conditions in the core at the ignition of helium are very different in low-mass stars (which have degenerate cores) from stars of higher mass (with non-degenerate cores). The electrons in the core of a 1M star are completely degenerate by the time the s ...
A near IR adaptive optics search for faint companions to early
... We suspect that it is a highly reddened (J − K = 2.4) background star. In this region of sky there are other multiple systems with similar proper motions and radial velocities (e.g. HR 3283, 3322, 3359). Therefore, NO Pup belongs to an association. HD 108248/49/50 = α1,2 Cru. The coronographic image ...
... We suspect that it is a highly reddened (J − K = 2.4) background star. In this region of sky there are other multiple systems with similar proper motions and radial velocities (e.g. HR 3283, 3322, 3359). Therefore, NO Pup belongs to an association. HD 108248/49/50 = α1,2 Cru. The coronographic image ...
Asteroseismology of Solar-Like Stars
... The two types of standing wave oscillations within a star are called g (gravity) and p (pressure) modes. In gravity modes the restoring force for the oscillation is the gradient of the gravitational acceleration within the star, they are also known as buoyancy waves. A parcel of gas within a star wi ...
... The two types of standing wave oscillations within a star are called g (gravity) and p (pressure) modes. In gravity modes the restoring force for the oscillation is the gradient of the gravitational acceleration within the star, they are also known as buoyancy waves. A parcel of gas within a star wi ...
Preface 1 PDF
... can be inferred. Thanks to helioseismology, we know that the Sun rotates as a solid body in the radiative interior and that the convective envelope rotates differentially, with a shear layer in between. Such a shear is thought to be one of the ways in which the large-scale magnetic field of the Sun c ...
... can be inferred. Thanks to helioseismology, we know that the Sun rotates as a solid body in the radiative interior and that the convective envelope rotates differentially, with a shear layer in between. Such a shear is thought to be one of the ways in which the large-scale magnetic field of the Sun c ...
The DBV stars: Progress and problems
... ’whitedwarfs. There are at least two possible progenitors of DB white dwarfs: the PG 1159 stars and the interacting binary white dwarfs. Dehner & Kawaler (1995) show the seismological helium profile of PG 1159-035 can evolve into something similar to what Bradley & Winget (1994) derive for GD 358, b ...
... ’whitedwarfs. There are at least two possible progenitors of DB white dwarfs: the PG 1159 stars and the interacting binary white dwarfs. Dehner & Kawaler (1995) show the seismological helium profile of PG 1159-035 can evolve into something similar to what Bradley & Winget (1994) derive for GD 358, b ...
On the nature and detectability of Type Ib/c supernova progenitors
... stars through stellar-wind mass-loss. In binary systems, lowermass helium stars can be produced via mass transfer. As discussed by Yoon et al. (2010), such relatively low-mass helium stars can retain a large amount of helium in the envelope and expand to a large radius during the late evolutionary s ...
... stars through stellar-wind mass-loss. In binary systems, lowermass helium stars can be produced via mass transfer. As discussed by Yoon et al. (2010), such relatively low-mass helium stars can retain a large amount of helium in the envelope and expand to a large radius during the late evolutionary s ...
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.