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... the comoving SFR density At face value it implies the universe was much more active in the past (z ~1 - 2) but what happens earlier is unclear There are many complications of interpretation, including the reliability of each SFR ...
... the comoving SFR density At face value it implies the universe was much more active in the past (z ~1 - 2) but what happens earlier is unclear There are many complications of interpretation, including the reliability of each SFR ...
Spectral classification of blue supergiants in M31
... few tens of solar masses. At the same time, they are enormously large with radii comparable to the Earth’s orbit. Because of those features they have been identified as very promising targets for stellar astronomy, enabling quantitative spectral analysis outside the Milky Way [4, 1]. This work adds ...
... few tens of solar masses. At the same time, they are enormously large with radii comparable to the Earth’s orbit. Because of those features they have been identified as very promising targets for stellar astronomy, enabling quantitative spectral analysis outside the Milky Way [4, 1]. This work adds ...
Slide 1 - Documents
... The origin of comets and minor bodies of the Solar System (SS) has been and still is an unsolved puzzle. Oort (1950, Bull. Astron. Inst. Netherlands 11, 91) supported the idea of the existence of a distant cometary reservoir located far from the Sun but still gravitationally bound to the SS, the so ...
... The origin of comets and minor bodies of the Solar System (SS) has been and still is an unsolved puzzle. Oort (1950, Bull. Astron. Inst. Netherlands 11, 91) supported the idea of the existence of a distant cometary reservoir located far from the Sun but still gravitationally bound to the SS, the so ...
Lecture 29 Our Galaxy: "Milky Way"
... Galactic Rotation Galactic material must be in some kind of orbit around the center, or gravity would pull everything into the center! • Rotation of Galaxy is real tough to measure (can't actually see rotation in our lifetime), but get a rough idea as follows, mainly from doppler radial velocities: ...
... Galactic Rotation Galactic material must be in some kind of orbit around the center, or gravity would pull everything into the center! • Rotation of Galaxy is real tough to measure (can't actually see rotation in our lifetime), but get a rough idea as follows, mainly from doppler radial velocities: ...
A New Hypothesis On The Origin and Formation of The Solar And
... near-circular planetary orbits for billions of years, as well as why some low mass stars have planets while others have nothing around them, not even dust rings. In this study, we propose that 4.6 billion years ago our Sun along with its planets and satellites were born from a small group of dense c ...
... near-circular planetary orbits for billions of years, as well as why some low mass stars have planets while others have nothing around them, not even dust rings. In this study, we propose that 4.6 billion years ago our Sun along with its planets and satellites were born from a small group of dense c ...
What is the biggest star? - University of Central Lancashire
... A really good question, we think the universe is about 13 billion years old and the first starts would have formed not long after the big bang, but those stars would have been a bit different than the stars we know today. Stars themselves can live for millions or even billions of years depending on ...
... A really good question, we think the universe is about 13 billion years old and the first starts would have formed not long after the big bang, but those stars would have been a bit different than the stars we know today. Stars themselves can live for millions or even billions of years depending on ...
PoS(HTRA-IV)044 - Proceeding of science
... are of course exceptions, but the huge amount of available stars up to V -band magnitude 16 allows to waste some of them. On the figure are also shown two K-band magnitude limits, that ensure stars above to be smaller than FS at 40 a.u and a wavelength of 550 nm. One is set in the situation where we ...
... are of course exceptions, but the huge amount of available stars up to V -band magnitude 16 allows to waste some of them. On the figure are also shown two K-band magnitude limits, that ensure stars above to be smaller than FS at 40 a.u and a wavelength of 550 nm. One is set in the situation where we ...
Document
... • Where ?: Filaments - not clusters or voids. • When?: Slowly - bulge, then disc and halo. • How?: Not understood and complicated (ie cannot simulate), but at least four phases/components: – Bulges formed like early ellipticals, smaller scale models of same: “dissipational collapse; – Discs form slo ...
... • Where ?: Filaments - not clusters or voids. • When?: Slowly - bulge, then disc and halo. • How?: Not understood and complicated (ie cannot simulate), but at least four phases/components: – Bulges formed like early ellipticals, smaller scale models of same: “dissipational collapse; – Discs form slo ...
BINARY STARS
... More recently, binary stars play another significant role in the discovery of many compact objects. These refer to stellar objects with extremely high densities, which may be white dwarfs, neutron stars or black holes, all of them have masses of the order of one to ten times the solar mass, compress ...
... More recently, binary stars play another significant role in the discovery of many compact objects. These refer to stellar objects with extremely high densities, which may be white dwarfs, neutron stars or black holes, all of them have masses of the order of one to ten times the solar mass, compress ...
The California Planet Survey II. A Saturn
... stars, the relationships between the physical characteristics of stars and the properties of their planets will come into sharper focus. We are monitoring a sample of 147 late K and early M stars as part of the California Planet Survey at Keck Observatory with a current temporal baseline of ≈ 12 yea ...
... stars, the relationships between the physical characteristics of stars and the properties of their planets will come into sharper focus. We are monitoring a sample of 147 late K and early M stars as part of the California Planet Survey at Keck Observatory with a current temporal baseline of ≈ 12 yea ...
Ch16_MilkyWayGalaxy
... • At a distance of 3 kpc, an arc of cold hydrogen sweeps outward at a speed exceeding 100 km/sec • A giant swarm of stars, packed in at millions of stars per cubic light-year, are arranged in an elongated structure about 1000 light-years across • Some energetic event, perhaps a supernova explosion, ...
... • At a distance of 3 kpc, an arc of cold hydrogen sweeps outward at a speed exceeding 100 km/sec • A giant swarm of stars, packed in at millions of stars per cubic light-year, are arranged in an elongated structure about 1000 light-years across • Some energetic event, perhaps a supernova explosion, ...
Document
... poorly defined. Hence, a distance determined by this method should be regarded as an estimate – This method has nothing to do with Parallax! ...
... poorly defined. Hence, a distance determined by this method should be regarded as an estimate – This method has nothing to do with Parallax! ...
IAU TAD report - Cornell Astronomy
... Lovelace (Cornell University, USA) to Almaty, Kazakstan in frames of the IAU TAD program 9-15 August, 2008 We visited several institutions in Almaty, gave lectures, talked to scientists. Historically, Kazakhstan has strong scientific base due to strong ties with Russia and with the fact that many sc ...
... Lovelace (Cornell University, USA) to Almaty, Kazakstan in frames of the IAU TAD program 9-15 August, 2008 We visited several institutions in Almaty, gave lectures, talked to scientists. Historically, Kazakhstan has strong scientific base due to strong ties with Russia and with the fact that many sc ...
L173 HAT-P-5b: A JUPITER-LIKE HOT JUPITER TRANSITING A
... from a joint fit based on the six distinct transit events, observed with the FLWO 1.2 m and Wise 1 m telescopes. A circular orbit was assumed, based on our analysis above. We adopted a quadratic limb-darkening law for the star, and took the appropriate coefficients from Claret (2004) for both the Sl ...
... from a joint fit based on the six distinct transit events, observed with the FLWO 1.2 m and Wise 1 m telescopes. A circular orbit was assumed, based on our analysis above. We adopted a quadratic limb-darkening law for the star, and took the appropriate coefficients from Claret (2004) for both the Sl ...
Properties of Stars Measuring Stars Apparent Magnitude, m Range
... Stellar Parallax The parallax angle is the maximum difference in angle you sight on a star when your position changes by 1 AU When the parallax angle is one arc second, the star is ...
... Stellar Parallax The parallax angle is the maximum difference in angle you sight on a star when your position changes by 1 AU When the parallax angle is one arc second, the star is ...
Galaxies
... • The first formation was about 13 billion years ago. • Gravity pulled small gas clouds together—with enough density, stars form. • These first galaxies were elliptical shapes. ...
... • The first formation was about 13 billion years ago. • Gravity pulled small gas clouds together—with enough density, stars form. • These first galaxies were elliptical shapes. ...
STScI 2005
... • Stars generally form with a frequency that decreases with increasing mass for masses greater than ~1 M: ...
... • Stars generally form with a frequency that decreases with increasing mass for masses greater than ~1 M: ...
The Stellar Population And Origin Of The Mysterious K.V. Getman
... The mysterious high galactic latitude cometary globule (CG) CG12 has been observed with the ACIS detector on board the Chandra X-ray Observatory. We detect 128 X-ray sources, of which a half are likely young stars formed within the globule's head. This new population of >=50 T-Tauri stars and one ne ...
... The mysterious high galactic latitude cometary globule (CG) CG12 has been observed with the ACIS detector on board the Chandra X-ray Observatory. We detect 128 X-ray sources, of which a half are likely young stars formed within the globule's head. This new population of >=50 T-Tauri stars and one ne ...
model of convection
... • Goal: provide the community with images at few mas spatial resolution, in the J,H, K and N-band, in one night of observation, down to a magnitude K~11 ...
... • Goal: provide the community with images at few mas spatial resolution, in the J,H, K and N-band, in one night of observation, down to a magnitude K~11 ...
Astro 3303 - Cornell Astronomy
... • Because of the Earth's revolution around the Sun, nearby stars appear to move with respect to very distant stars. • The parallax of a star is the apparent angular size of the ellipse that a nearby star appears to trace against the background stars. • A parsec is the distance at which a star would ...
... • Because of the Earth's revolution around the Sun, nearby stars appear to move with respect to very distant stars. • The parallax of a star is the apparent angular size of the ellipse that a nearby star appears to trace against the background stars. • A parsec is the distance at which a star would ...
Line-profile tomography of exoplanet transits – II. A gas
... for main-sequence A-F-type stars, suggesting the possible presence of close-in planets, but measuring the small reflex motion that would confirm their planetary origin is generally not possible for these line-poor, fast-rotating stars. The hottest star known to passes a transiting planet until now i ...
... for main-sequence A-F-type stars, suggesting the possible presence of close-in planets, but measuring the small reflex motion that would confirm their planetary origin is generally not possible for these line-poor, fast-rotating stars. The hottest star known to passes a transiting planet until now i ...
The chemical composition of TS 01, the most oxygen
... consider observations of TS 01 made with the Hubble Space Telescope (HST) and the Far Ultraviolet Spectroscopic Explorer (FUSE). As a result, some of their “predicted” line intensities are in conflict with what is actually observed in the UV. HST observations were obtained in 2003 and presented in a ...
... consider observations of TS 01 made with the Hubble Space Telescope (HST) and the Far Ultraviolet Spectroscopic Explorer (FUSE). As a result, some of their “predicted” line intensities are in conflict with what is actually observed in the UV. HST observations were obtained in 2003 and presented in a ...
Dark Stars: Dark Matter Annihilation in the First Stars.
... further DM is captured by the star. See also work of Fabio Iocco and Gianfranco Bertone. • The refueling can only persist as long as the DS resides in a DM rich environment, I.e. near the center of the DM halo. But the halo merges with other objects so that a reasonable guess for the lifetime would ...
... further DM is captured by the star. See also work of Fabio Iocco and Gianfranco Bertone. • The refueling can only persist as long as the DS resides in a DM rich environment, I.e. near the center of the DM halo. But the halo merges with other objects so that a reasonable guess for the lifetime would ...
Incredible Shrinking Stars
... smaller than the stellar core. The stellar core was rotating (because it was part of a rotating star). When the core collapses, the rotation is concentrated (sort of) in the neutron. Consequently, tbe neutron star ends up spinning very rapidly 4. The interior of a neutron star consists of neutrons. ...
... smaller than the stellar core. The stellar core was rotating (because it was part of a rotating star). When the core collapses, the rotation is concentrated (sort of) in the neutron. Consequently, tbe neutron star ends up spinning very rapidly 4. The interior of a neutron star consists of neutrons. ...
A Reservoir of Ionized Gas in the Galactic Halo to Sustain Star
... intergalactic medium (IGM) through outflows driven by galactic “feedback”, galactic winds powered by massive stars and their death and from massive black holes. Some of this material may return to the central galaxy as recycled infalling matter – the galactic fountain mechanism (2, 3). The circumga ...
... intergalactic medium (IGM) through outflows driven by galactic “feedback”, galactic winds powered by massive stars and their death and from massive black holes. Some of this material may return to the central galaxy as recycled infalling matter – the galactic fountain mechanism (2, 3). The circumga ...
Planetary nebula
![](https://commons.wikimedia.org/wiki/Special:FilePath/NGC6543.jpg?width=300)
A planetary nebula, often abbreviated as PN or plural PNe, is a kind of emission nebula consisting of an expanding glowing shell of ionized gas ejected from old red giant stars late in their lives. The word ""nebula"" is Latin for mist or cloud and the term ""planetary nebula"" is a misnomer that originated in the 1780s with astronomer William Herschel because when viewed through his telescope, these objects appeared to him to resemble the rounded shapes of planets. Herschel's name for these objects was popularly adopted and has not been changed. They are a relatively short-lived phenomenon, lasting a few tens of thousands of years, compared to a typical stellar lifetime of several billion years.A mechanism for formation of most planetary nebulae is thought to be the following: at the end of the star's life, during the red giant phase, the outer layers of the star are expelled by strong stellar winds. Eventually, after most of the red giant's atmosphere is dissipated, the exposed hot, luminous core emits ultraviolet radiation to ionize the ejected outer layers of the star. Absorbed ultraviolet light energises the shell of nebulous gas around the central star, appearing as a bright coloured planetary nebula at several discrete visible wavelengths.Planetary nebulae may play a crucial role in the chemical evolution of the Milky Way, returning material to the interstellar medium from stars where elements, the products of nucleosynthesis (such as carbon, nitrogen, oxygen and neon), have been created. Planetary nebulae are also observed in more distant galaxies, yielding useful information about their chemical abundances.In recent years, Hubble Space Telescope images have revealed many planetary nebulae to have extremely complex and varied morphologies. About one-fifth are roughly spherical, but the majority are not spherically symmetric. The mechanisms which produce such a wide variety of shapes and features are not yet well understood, but binary central stars, stellar winds and magnetic fields may play a role.