THE PRIMORDIAL HELIUM ABUNDANCE Manuel Peimbert
... age of about 4.5 billion years. Planetary nebulae are clouds of ionized gas ejected by intermediate mass stars when they evolve from the stage of red giants to the stage of white dwarfs; galactic disk planetary nebulae have typical ages of about one billion years, while halo planetary nebulae have t ...
... age of about 4.5 billion years. Planetary nebulae are clouds of ionized gas ejected by intermediate mass stars when they evolve from the stage of red giants to the stage of white dwarfs; galactic disk planetary nebulae have typical ages of about one billion years, while halo planetary nebulae have t ...
the first three thresholds - McGraw
... there is a vast multidimensional “multiverse” within which universes keep appearing, each with its own distinctive features, so that our universe may be one of countless billions of universes. The modern origin story is also different from other origin stories in important ways. Above all, it offers ...
... there is a vast multidimensional “multiverse” within which universes keep appearing, each with its own distinctive features, so that our universe may be one of countless billions of universes. The modern origin story is also different from other origin stories in important ways. Above all, it offers ...
Silicon isotopic abundance toward evolved stars and its application
... Most of the presolar grains have 29 Si/30 Si ratios around 1.5, but evidence of lower 29 Si/30 Si ratios are also found in presolar SiC grains, for instance, types X2 and Z in Fig. 3. The type Z grains may have originated from a nearby evolved star (see also Zinner et al. 2006). Additionally, the ty ...
... Most of the presolar grains have 29 Si/30 Si ratios around 1.5, but evidence of lower 29 Si/30 Si ratios are also found in presolar SiC grains, for instance, types X2 and Z in Fig. 3. The type Z grains may have originated from a nearby evolved star (see also Zinner et al. 2006). Additionally, the ty ...
Next Generation VLA Science White Paper
... previous capabilities and it is a stunning tool to study dust emission, excited gas, and active regions. Though still revolutionary at ν ∼ 70–115 GHz, ALMA in its current (nearly final) form would still require ∼ 15 hours to produce a 100 CO map of a nearby galaxy (σ = 0.2 K, ∆v = 5 km s−1 ). To wor ...
... previous capabilities and it is a stunning tool to study dust emission, excited gas, and active regions. Though still revolutionary at ν ∼ 70–115 GHz, ALMA in its current (nearly final) form would still require ∼ 15 hours to produce a 100 CO map of a nearby galaxy (σ = 0.2 K, ∆v = 5 km s−1 ). To wor ...
An Unbiased Near-infrared Interferometric Survey for Hot
... underlying planetary system. While this would be a very interesting scenario, it is questionable whether all systems observed are likely to meet these constraints. A combination of planetesimaldriven migration and dust trapping could explain the presence of the detected dust. Potential dust-trapping ...
... underlying planetary system. While this would be a very interesting scenario, it is questionable whether all systems observed are likely to meet these constraints. A combination of planetesimaldriven migration and dust trapping could explain the presence of the detected dust. Potential dust-trapping ...
A cold detached dust envelope around an oxygen-rich Mira
... boundary is required for the circumstellar dust envelope in this case (Hashimoto 1994, 1995). (4) Or, some circumstellar mechanisms other than dust grains may produce the infrared excess. For example, strong line emission from circumstellar molecules such as H2 O may cause the reddening. In any case ...
... boundary is required for the circumstellar dust envelope in this case (Hashimoto 1994, 1995). (4) Or, some circumstellar mechanisms other than dust grains may produce the infrared excess. For example, strong line emission from circumstellar molecules such as H2 O may cause the reddening. In any case ...
Autumn 2016 Midterm Review - Autumn 2015 Questions
... 23. Geomagnetic storms provide the energy that produce the aurorae at Earth’s poles. Complete the following sentence: The magnetic field of the Earth interacts with the solar wind, a. stretches almost to breaking, snaps back, and excites electrons in the atmosphere. b. causing the charged particles ...
... 23. Geomagnetic storms provide the energy that produce the aurorae at Earth’s poles. Complete the following sentence: The magnetic field of the Earth interacts with the solar wind, a. stretches almost to breaking, snaps back, and excites electrons in the atmosphere. b. causing the charged particles ...
The evolution of the Sun`s birth cluster and the search for the solar
... Ongoing surveys of our galaxy, in particular the Gaia mission (Lindegren et al. 2008) and the GALAH survey (De Silva et al. 2015), will provide large samples of stars with accurately determined distances, space motions, and chemical abundance patterns, thus enabling a much improved search for the su ...
... Ongoing surveys of our galaxy, in particular the Gaia mission (Lindegren et al. 2008) and the GALAH survey (De Silva et al. 2015), will provide large samples of stars with accurately determined distances, space motions, and chemical abundance patterns, thus enabling a much improved search for the su ...
Module 11.1.1: Galaxies: Morphology and the Hubble Sequence
... universe now, and their masses range from hundreds of million to maybe trillion solar masses, containing up to couple of hundred billion stars. [slide 3] The first thing that any empirical ...
... universe now, and their masses range from hundreds of million to maybe trillion solar masses, containing up to couple of hundred billion stars. [slide 3] The first thing that any empirical ...
Zapartas_deMink_Izzard_AA_2017
... from progenitors in binary systems with most of them being of intermediate mass. We discuss these late ccSNe in section 3 and describe the various evolutionary channels that produce them. We further describe the outcome of an extensive study of the robustness of our results against variations in the ...
... from progenitors in binary systems with most of them being of intermediate mass. We discuss these late ccSNe in section 3 and describe the various evolutionary channels that produce them. We further describe the outcome of an extensive study of the robustness of our results against variations in the ...
preprint, pdf version - LESIA
... of positive and negative detections also result in significant improvements in the TNO ephemeris, thus refining the orbit and substantially increasing the accuracy of the subsequent occultation predictions. Improving the chances of success minimizes the money and time spent in the complex internatio ...
... of positive and negative detections also result in significant improvements in the TNO ephemeris, thus refining the orbit and substantially increasing the accuracy of the subsequent occultation predictions. Improving the chances of success minimizes the money and time spent in the complex internatio ...
Astronomy 250 - University of Victoria
... Every measured quantity will always have an associated uncertainy. Errors can occur, for example, because of the limitations of the measuring device, because of systematic offsets (see below), because of legitimate dispersions in the data, etc. Example: Suppose you are trying to measure the brightne ...
... Every measured quantity will always have an associated uncertainy. Errors can occur, for example, because of the limitations of the measuring device, because of systematic offsets (see below), because of legitimate dispersions in the data, etc. Example: Suppose you are trying to measure the brightne ...
18_Testbank - Lick Observatory
... D) If the Sun magically disappeared and was replaced by a black hole of the same mass, Earth would soon be sucked into the black hole. E) If you fell into a black hole, you would experience time to be running normally as you plunged rapidly across the event horizon. Answer: D 28) In some cases, a su ...
... D) If the Sun magically disappeared and was replaced by a black hole of the same mass, Earth would soon be sucked into the black hole. E) If you fell into a black hole, you would experience time to be running normally as you plunged rapidly across the event horizon. Answer: D 28) In some cases, a su ...
Evolution of Population II Stars in the Helium
... some definite value, without mixing between the hydrogen-rich envelope and the helium region. Evolution of Population I stars with 15.6 M 0 4>, 5> and 4 M 0 6> in the heliumburning phase has been investigated taking into account the effect of helium depletion on the mean molecular weight and on the ...
... some definite value, without mixing between the hydrogen-rich envelope and the helium region. Evolution of Population I stars with 15.6 M 0 4>, 5> and 4 M 0 6> in the heliumburning phase has been investigated taking into account the effect of helium depletion on the mean molecular weight and on the ...
A spectroscopic investigation of the O-type star - ORBi
... Context. Establishing the multiplicity of O-type stars is the first step towards accurately determining their stellar parameters. Moreover, the distribution of the orbital parameters provides observational clues to the way that O-type stars form and to the interactions during their evolution. Aims. ...
... Context. Establishing the multiplicity of O-type stars is the first step towards accurately determining their stellar parameters. Moreover, the distribution of the orbital parameters provides observational clues to the way that O-type stars form and to the interactions during their evolution. Aims. ...
Using time to measure distance - AS-A2
... 11. In the 1920s. Vesto Slipher and Edwin Hubble gathered data that showed that distant galaxies are all moving away from us and that the speed at which they are moving away is directly proportional to their distance. How do cosmologists account for these observations? ...
... 11. In the 1920s. Vesto Slipher and Edwin Hubble gathered data that showed that distant galaxies are all moving away from us and that the speed at which they are moving away is directly proportional to their distance. How do cosmologists account for these observations? ...
Chapter15.1
... It would be only 1/3 as bright. It would be only 1/6 as bright. It would be only 1/9 as bright. It would be three times brighter. ...
... It would be only 1/3 as bright. It would be only 1/6 as bright. It would be only 1/9 as bright. It would be three times brighter. ...
PDF format
... • Stellar properties depend on both mass and age: Those that have finished fusing H to He in their cores are no longer on the main sequence. • All stars become larger and redder after exhausting their core hydrogen: giants and ...
... • Stellar properties depend on both mass and age: Those that have finished fusing H to He in their cores are no longer on the main sequence. • All stars become larger and redder after exhausting their core hydrogen: giants and ...
Characterization of the four new transiting planets KOI
... on the observation, we detected two sets of barely resolved spectral lines separated by a few km s−1 , or a unique set of spectral lines that we interpreted as the superposition of the two sets being located at a similar radial velocity at that time. The corresponding radial velocities and bisector ...
... on the observation, we detected two sets of barely resolved spectral lines separated by a few km s−1 , or a unique set of spectral lines that we interpreted as the superposition of the two sets being located at a similar radial velocity at that time. The corresponding radial velocities and bisector ...
The physics and modes of star cluster formation: observations
... their formation and early evolution, are completely embedded in molecular gas and dust. They are thus obscured from view at optical wavelengths, where the traditional astronomical techniques are most effective. Fortunately, molecular clouds are considerably less opaque at infrared wavelengths and th ...
... their formation and early evolution, are completely embedded in molecular gas and dust. They are thus obscured from view at optical wavelengths, where the traditional astronomical techniques are most effective. Fortunately, molecular clouds are considerably less opaque at infrared wavelengths and th ...
Stellar kinematics
Stellar kinematics is the study of the movement of stars without needing to understand how they acquired their motion. This differs from stellar dynamics, which takes into account gravitational effects. The motion of a star relative to the Sun can provide useful information about the origin and age of a star, as well as the structure and evolution of the surrounding part of the Milky Way.In astronomy, it is widely accepted that most stars are born within molecular clouds known as stellar nurseries. The stars formed within such a cloud compose open clusters containing dozens to thousands of members. These clusters dissociate over time. Stars that separate themselves from the cluster's core are designated as members of the cluster's stellar association. If the remnant later drifts through the Milky Way as a coherent assemblage, then it is termed a moving group.