The XMM-Newton Bright Serendipitous Survey
... low/medium resolution (from ∼250 to 450) grisms to maximize the wavelength coverage. For the data reduction we have used the IRAF longslit package. The spectra have been wavelength calibrated using a reference spectrum and flux calibrated using photometric standard stars observed during the same nig ...
... low/medium resolution (from ∼250 to 450) grisms to maximize the wavelength coverage. For the data reduction we have used the IRAF longslit package. The spectra have been wavelength calibrated using a reference spectrum and flux calibrated using photometric standard stars observed during the same nig ...
The Lupus clouds - European Southern Observatory
... evolution and perhaps the origin of the complex. The entire variety of objects related to the various stages of early stellar evolution are represented in Lupus, including some of the best studied T Tauri stars like RU Lup. The determination of many properties of the clouds, as well as their associa ...
... evolution and perhaps the origin of the complex. The entire variety of objects related to the various stages of early stellar evolution are represented in Lupus, including some of the best studied T Tauri stars like RU Lup. The determination of many properties of the clouds, as well as their associa ...
Unfolding the Milky Way bulge - International Max Planck Research
... Example of the final output of the synthesis procedure in order to derive the abundances of Mg (upper left), Ca (upper right), Ti (lower left) and Si (lower right). Observed spectrum for target star 212175c6 is plotted as black dots and the red dashed line shows the synthetic spectrum using the best ...
... Example of the final output of the synthesis procedure in order to derive the abundances of Mg (upper left), Ca (upper right), Ti (lower left) and Si (lower right). Observed spectrum for target star 212175c6 is plotted as black dots and the red dashed line shows the synthetic spectrum using the best ...
THE 2MASS WIDE-FIELD T DWARF SEARCH. II. DISCOVERY OF
... Survey. These objects, 2MASS 03486022, 2MASS 05160445, and 2MASS 22284310, have classifications T7, T5.5, and T6.5, respectively. Using linear absolute magnitude/spectral type relations derived from T dwarfs with measured parallaxes, we estimate spectrophotometric distances for these discoveries; ...
... Survey. These objects, 2MASS 03486022, 2MASS 05160445, and 2MASS 22284310, have classifications T7, T5.5, and T6.5, respectively. Using linear absolute magnitude/spectral type relations derived from T dwarfs with measured parallaxes, we estimate spectrophotometric distances for these discoveries; ...
Astronomy Astrophysics
... crowded regions, we performed point spread function (PSF) photometry of 10 × 10 arcmin fields surrounding each selected candidate. We used the VVV-SkZ pipeline, which is an automatic PSF-fitting photometric pipeline for the VVV survey (Mauro et al. 2013). Where possible, the saturated stars (usually ...
... crowded regions, we performed point spread function (PSF) photometry of 10 × 10 arcmin fields surrounding each selected candidate. We used the VVV-SkZ pipeline, which is an automatic PSF-fitting photometric pipeline for the VVV survey (Mauro et al. 2013). Where possible, the saturated stars (usually ...
Understanding Variable Stars - Central Florida Astronomical Society
... 2.5 The passbands of the visual (UBV) and infrared filters (RIJHKL) in the UBV photometric system (lower panel), compared with the spectrum of the sun (lower panel), and the transparency of the earth’s atmosphere (upper panel) 23 2.6 Parallax is the apparent change in the position of a star on the sk ...
... 2.5 The passbands of the visual (UBV) and infrared filters (RIJHKL) in the UBV photometric system (lower panel), compared with the spectrum of the sun (lower panel), and the transparency of the earth’s atmosphere (upper panel) 23 2.6 Parallax is the apparent change in the position of a star on the sk ...
my dissertation (PhD. Thesis) - Argelander
... Figure 1.4: M 83 (NGC 5236): A barred galaxy; Our Milky way is also known to have a small bar (ESO-La Silla, 1.54 m + DFOSC). ...
... Figure 1.4: M 83 (NGC 5236): A barred galaxy; Our Milky way is also known to have a small bar (ESO-La Silla, 1.54 m + DFOSC). ...
Communications in Asteroseismology
... “Mi-shell Brezhair” in France and Quebec! Mike is a man of many names, but for his more than 35 postgraduate students and many others he is also known as “mentor”, and all of us know him as “friend” and “colleague”. I (DWK) was Mike’s first PhD student at the University of Texas over 30 years ago. Wh ...
... “Mi-shell Brezhair” in France and Quebec! Mike is a man of many names, but for his more than 35 postgraduate students and many others he is also known as “mentor”, and all of us know him as “friend” and “colleague”. I (DWK) was Mike’s first PhD student at the University of Texas over 30 years ago. Wh ...
X-ray astronomy of stellar coronae (Review)
... seem to be ubiquitous among stars, but neither do we understand precisely why, nor have we fully understood the bewildering variety of plasma physical mechanisms that act in stellar environments. We have found magnetic fields on stars that ought to have none so long as we appeal to our limited under ...
... seem to be ubiquitous among stars, but neither do we understand precisely why, nor have we fully understood the bewildering variety of plasma physical mechanisms that act in stellar environments. We have found magnetic fields on stars that ought to have none so long as we appeal to our limited under ...
Differential rotation in Sun-like stars from surface variability and
... rate on the MS and beyond. The exact nature however, of the AM evolution during these very early phases of stellar evolution is still poorly understood. This is in part because the only available indicator of the AM of a star is its surface rotation rate. For PMS stars this is measured by either spe ...
... rate on the MS and beyond. The exact nature however, of the AM evolution during these very early phases of stellar evolution is still poorly understood. This is in part because the only available indicator of the AM of a star is its surface rotation rate. For PMS stars this is measured by either spe ...
Europium, Samarium, and Neodymium Isotopic Fractions in Metal
... analyzing each line of each species (Appendix A), and we include our computations of the hyperfine structure subcomponents for both Sm (Appendix B) and Nd (Appendix C). 2. OBSERVATIONS 2.1. Selection of Target Stars We choose two bright, metal-poor giants for our analysis, HD 175305 and HD 196944. T ...
... analyzing each line of each species (Appendix A), and we include our computations of the hyperfine structure subcomponents for both Sm (Appendix B) and Nd (Appendix C). 2. OBSERVATIONS 2.1. Selection of Target Stars We choose two bright, metal-poor giants for our analysis, HD 175305 and HD 196944. T ...
the PDF - Montana State University
... remains a mystery. In this work, we place the solar cycle in a broader context by examining the long-term variability of solar analog stars within 5% of the solar effective temperature, but varied in rotation rate and metallicity. Emission in the Fraunhofer H & K line cores from singly-ionized calci ...
... remains a mystery. In this work, we place the solar cycle in a broader context by examining the long-term variability of solar analog stars within 5% of the solar effective temperature, but varied in rotation rate and metallicity. Emission in the Fraunhofer H & K line cores from singly-ionized calci ...
Tuomas Kangas
... Stars are divided into spectral classes depending on their effective (surface) temperatures, which determine their intrinsic colors. The sequence from hottest to coolest is O–B–A–F–G–K–M, followed by the even cooler brown dwarfs. O-type stars are blue, with temperatures T & 20000 K, while red M-type ...
... Stars are divided into spectral classes depending on their effective (surface) temperatures, which determine their intrinsic colors. The sequence from hottest to coolest is O–B–A–F–G–K–M, followed by the even cooler brown dwarfs. O-type stars are blue, with temperatures T & 20000 K, while red M-type ...
A spectroscopic study of detached binary systems using precise radial velocities
... orbits, whilst others result from much more active processes, such as mass exchange leading to intense radiation emissions. A complete understanding of a binary system’s orbital characteristics, as well as the measurement of the all-important stellar masses, is almost always only achieved after the ...
... orbits, whilst others result from much more active processes, such as mass exchange leading to intense radiation emissions. A complete understanding of a binary system’s orbital characteristics, as well as the measurement of the all-important stellar masses, is almost always only achieved after the ...
The physics of line-driven winds of hot massive stars
... see in her or his life. One is overwhelmed by the immensity of our galaxy (see Figure 1.1), and is intrigued by the presence of two of its satellites, the Large and Small Magellanic Cloud. Galaxies are comprised of stars and clouds of gas. Stars that appear equally bright to the naked eye may either ...
... see in her or his life. One is overwhelmed by the immensity of our galaxy (see Figure 1.1), and is intrigued by the presence of two of its satellites, the Large and Small Magellanic Cloud. Galaxies are comprised of stars and clouds of gas. Stars that appear equally bright to the naked eye may either ...
Here - NASA/IPAC Extragalactic Database
... higher Mneb or Q(H0 ). The number fractions of He and heavy elements (C, N, O. . . )† in real nebulae are about 10% and 0.1% respectively. Helium, although ten times less abundant than hydrogen, is the dominant source of absorption of photons at energies above 24.4 eV. For order of magnitudes estima ...
... higher Mneb or Q(H0 ). The number fractions of He and heavy elements (C, N, O. . . )† in real nebulae are about 10% and 0.1% respectively. Helium, although ten times less abundant than hydrogen, is the dominant source of absorption of photons at energies above 24.4 eV. For order of magnitudes estima ...
Giant star seismology
... Asteroseismology – the study of global properties of stars and their internal structure through their global intrinsic oscillations – is already more than a century old. An early remarkable result was obtained for Cepheids revealing the period-luminosity relation (Leavitt and Pickering, 1912), which ...
... Asteroseismology – the study of global properties of stars and their internal structure through their global intrinsic oscillations – is already more than a century old. An early remarkable result was obtained for Cepheids revealing the period-luminosity relation (Leavitt and Pickering, 1912), which ...
Stars, Galaxies, and Beyond
... Ivezić for allowing me this opportunity to explore these many important topics in astrophysics. Sources: The materials in this summary derive from the lecture notes, the assigned textbook, and many Web and published scientific articles and other sources as noted. I do not consider Wikipedia to be a ...
... Ivezić for allowing me this opportunity to explore these many important topics in astrophysics. Sources: The materials in this summary derive from the lecture notes, the assigned textbook, and many Web and published scientific articles and other sources as noted. I do not consider Wikipedia to be a ...
Gamma-Ray Bursts and Puzzles of Core
... First 21 GRB hosts: The Hubble diagram for GRB host galaxies with known (before June 2002) observable stellar magnitudes (or with upper R limits) and spectroscopic red shifts against the background of results of the photometric measurement of z applied to galaxies from the Hubble Deep Field (HDF) b ...
... First 21 GRB hosts: The Hubble diagram for GRB host galaxies with known (before June 2002) observable stellar magnitudes (or with upper R limits) and spectroscopic red shifts against the background of results of the photometric measurement of z applied to galaxies from the Hubble Deep Field (HDF) b ...
X-Ray Spectroscopy of Stars
... giants of spectral type M. But even for those two classes, important exceptions exist. X-rays have been identified from the most massive and hottest stars, i.e., O-type and Wolf-Rayet stars, for which shocks forming in unstable winds are held responsible for the production of million-degree plasma a ...
... giants of spectral type M. But even for those two classes, important exceptions exist. X-rays have been identified from the most massive and hottest stars, i.e., O-type and Wolf-Rayet stars, for which shocks forming in unstable winds are held responsible for the production of million-degree plasma a ...
The evolution of low-metallicity massive stars - Argelander
... stars with a companion, there are stars that mostly emit red light, or yellow light, or blue light. There are even stars that emit light in the invisible ultraviolet band and so on, and there are stars surrounded by shining nebulae. Then, there are giant congregations of stars called clusters, and t ...
... stars with a companion, there are stars that mostly emit red light, or yellow light, or blue light. There are even stars that emit light in the invisible ultraviolet band and so on, and there are stars surrounded by shining nebulae. Then, there are giant congregations of stars called clusters, and t ...
Abundances of the elements He to Ni in the atmosphere of Sirius A
... The diameter of Sirius A has been measured interferometrically (Kervella et al. 2003) as DA = (1.711 ± 0.013) D . The effective temperature T e = (9900±200) K from Strömgren colours (Lemke 1989), in agreement with the value of (9900±130) K derived from the luminosity and radius ( see also Code et a ...
... The diameter of Sirius A has been measured interferometrically (Kervella et al. 2003) as DA = (1.711 ± 0.013) D . The effective temperature T e = (9900±200) K from Strömgren colours (Lemke 1989), in agreement with the value of (9900±130) K derived from the luminosity and radius ( see also Code et a ...
Turbulence-driven Polar Winds from T Tauri Stars Energized by
... What sets the Sun’s mass loss? • Coronal heating must be ultimately responsible for the solar wind. • A fraction of the “coronal heating” is channeled downward by conduction. • Hammer (1982) & Withbroe (1988) suggested a balance between conduction (downward), enthalpy (upward), and radiation losses ...
... What sets the Sun’s mass loss? • Coronal heating must be ultimately responsible for the solar wind. • A fraction of the “coronal heating” is channeled downward by conduction. • Hammer (1982) & Withbroe (1988) suggested a balance between conduction (downward), enthalpy (upward), and radiation losses ...
Slide 1
... Start with Stars like our Sun • Mid-sized stars (between 8% and 8 times the mass of our Sun) all typically have a similar life • Smaller than 8% of the Sun won’t get hot enough to fuse hydrogen – Isn’t really a star at all – Call this a brown dwarf • More than 8 times the mass of our Sun ...
... Start with Stars like our Sun • Mid-sized stars (between 8% and 8 times the mass of our Sun) all typically have a similar life • Smaller than 8% of the Sun won’t get hot enough to fuse hydrogen – Isn’t really a star at all – Call this a brown dwarf • More than 8 times the mass of our Sun ...
Article PDF - IOPscience
... minutes apart and in the same band. Thus, the survey should have obtained about 16 observations in each band (for a total of 80), but due to bad weather and telescope downtime, fewer epochs were observed (∼70 on average). Unlike Hernitschek et al. (2016, see their Section 2.2), we do not use bit-flag ...
... minutes apart and in the same band. Thus, the survey should have obtained about 16 observations in each band (for a total of 80), but due to bad weather and telescope downtime, fewer epochs were observed (∼70 on average). Unlike Hernitschek et al. (2016, see their Section 2.2), we do not use bit-flag ...
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.