... study of McNamara & Redcorn (1977). These authors concluded, based on its apparently rich metallicity, that the star is not an RRc but a dwarf Cepheid (or RRs) which are considered more massive (1 − 2 M⊙ ) post main sequence stars than the less massive (0.5 − 0.7 M⊙ ) post giant branch stars. SS Psc ...
Discovery of White Dwarfs—8 Oct
... temperatures and approximately the same size. Dwarfs are most common. Giants are large. White dwarfs are small. ...
... temperatures and approximately the same size. Dwarfs are most common. Giants are large. White dwarfs are small. ...
Continuous Spectrum—Kirchoff`s First Law
... If we know the temperature of a main sequence star, we can estimate its absolute luminosity. Then a measurement of its apparent luminosity gives us the distance to the star ...
... If we know the temperature of a main sequence star, we can estimate its absolute luminosity. Then a measurement of its apparent luminosity gives us the distance to the star ...
Comet Lulin - indstate.edu
... February 2009, Comet Lulin will rise at about midnight local time, and will be about 6th or 7th magnitude. This won't be bright enough to go out and look at it with the naked eye, but any telescope or binoculars should allow you to see it. By the middle of February 2009, Comet Lulin will be about 5t ...
... February 2009, Comet Lulin will rise at about midnight local time, and will be about 6th or 7th magnitude. This won't be bright enough to go out and look at it with the naked eye, but any telescope or binoculars should allow you to see it. By the middle of February 2009, Comet Lulin will be about 5t ...
WORD - Astrophysics
... non-baryonic dark matter and of baryons compare? Similarly, stars clearly form(ed) at some rate from gas, but at what rate, where, with what stellar Initial Mass Function, and what were the effects of this star formation on the remaining gas? What is the connection between galaxies and the supermass ...
... non-baryonic dark matter and of baryons compare? Similarly, stars clearly form(ed) at some rate from gas, but at what rate, where, with what stellar Initial Mass Function, and what were the effects of this star formation on the remaining gas? What is the connection between galaxies and the supermass ...
NASA`s Spitzer Images Out-of-This
... view from Spitzer, the area around the invisible black hole is blue and the ring of stars, white. The black hole is huge, about 100 million times the mass of our sun, and is feeding off gas and dust along with the occasional unlucky star. Our Milky Way's central black hole is tame by comparison, wit ...
... view from Spitzer, the area around the invisible black hole is blue and the ring of stars, white. The black hole is huge, about 100 million times the mass of our sun, and is feeding off gas and dust along with the occasional unlucky star. Our Milky Way's central black hole is tame by comparison, wit ...
relax it`s only parallax!
... The positive value of the difference between these two angles is the angular shift due to Parallax, i.e. angular shift = | first angle – second angle | Angular shift = ____________________ Next, use the tape measure to measure the baseline between your two observing positions in feet: Baseline = __ ...
... The positive value of the difference between these two angles is the angular shift due to Parallax, i.e. angular shift = | first angle – second angle | Angular shift = ____________________ Next, use the tape measure to measure the baseline between your two observing positions in feet: Baseline = __ ...
Observers` Forum - British Astronomical Association
... SCT GPS which had been used since September 2003 for the study of variable stars, in particular cataclysmic variables. After observing variables with Newtonians on various mounts for nearly 35 years, the change to a computer controlled telescope had been, for me, a major one. The Meade was of except ...
... SCT GPS which had been used since September 2003 for the study of variable stars, in particular cataclysmic variables. After observing variables with Newtonians on various mounts for nearly 35 years, the change to a computer controlled telescope had been, for me, a major one. The Meade was of except ...
Tutor Marked Assignment
... (b) What is H-R diagram? Discuss the characteristic features of stars located in any two distinct regions of the H-R diagram. ...
... (b) What is H-R diagram? Discuss the characteristic features of stars located in any two distinct regions of the H-R diagram. ...
targets - siamois
... What do we need after CoRoT, that Kepler, and hopefully PLATO, will not provide? Doppler velocity (Space-borne observations are photometric) ...
... What do we need after CoRoT, that Kepler, and hopefully PLATO, will not provide? Doppler velocity (Space-borne observations are photometric) ...
CW9_MOST_GSphot_RK_v1
... HD209775 – MOST Observations HD209775 was one of 5 GUIDE STAR used to point to HD209458 (transiting planet system) MOST collected data during a ‘test’ run (~15days) in 2004 to probe the eclipse phase of HD209458 clearly revealing its multi-mode delta Scuti type ...
... HD209775 – MOST Observations HD209775 was one of 5 GUIDE STAR used to point to HD209458 (transiting planet system) MOST collected data during a ‘test’ run (~15days) in 2004 to probe the eclipse phase of HD209458 clearly revealing its multi-mode delta Scuti type ...
The cosmic distance scale
... Use the relation you found in one of the preparatory exercises and the min/max magnitudes of each Cepheid to calculate the observed mean magnitudes. These have to be corrected for interstellar extinction. The light traveling to us from M100 is not just passing through the vacuum of space, some of it ...
... Use the relation you found in one of the preparatory exercises and the min/max magnitudes of each Cepheid to calculate the observed mean magnitudes. These have to be corrected for interstellar extinction. The light traveling to us from M100 is not just passing through the vacuum of space, some of it ...
Lecture 1 - X-ray and Observational Astronomy Group
... Extends from 0.25-0.7R⊙ (the tachocline or interface layer). Energy transported by radiation. Photons scatter many times, take approx 105 years to reach interface layer. Density falls from 20 g/cm3 to 0.2 g/cm3, T falls from 7x106 K to 2x106 K over same distance. Tachocline (interface layer) : Lies ...
... Extends from 0.25-0.7R⊙ (the tachocline or interface layer). Energy transported by radiation. Photons scatter many times, take approx 105 years to reach interface layer. Density falls from 20 g/cm3 to 0.2 g/cm3, T falls from 7x106 K to 2x106 K over same distance. Tachocline (interface layer) : Lies ...
lecture_1_mbu - X-ray and Observational Astronomy Group
... Extends from 0.25-0.7R⊙ (the tachocline or interface layer). Energy transported by radiation. Photons scatter many times, take approx 105 years to reach interface layer. Density falls from 20 g/cm3 to 0.2 g/cm3, T falls from 7x106 K to 2x106 K over same distance. Tachocline (interface layer) : Lies ...
... Extends from 0.25-0.7R⊙ (the tachocline or interface layer). Energy transported by radiation. Photons scatter many times, take approx 105 years to reach interface layer. Density falls from 20 g/cm3 to 0.2 g/cm3, T falls from 7x106 K to 2x106 K over same distance. Tachocline (interface layer) : Lies ...
Stars, Galaxies, and the Universe Section 1
... • As gravity makes dense regions within a nebula more compact, these regions spin and shrink and begin to form a flattened disk. The disk has a central concentration of matter called a protostar. • The protostar continues to contract and increase in temperature for several million years. Eventually ...
... • As gravity makes dense regions within a nebula more compact, these regions spin and shrink and begin to form a flattened disk. The disk has a central concentration of matter called a protostar. • The protostar continues to contract and increase in temperature for several million years. Eventually ...
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... line in C-stars is strong, that of the TiO molecule in oxygen-rich stars of the same effective temperature is even more severe. The lower limit of Li abundance that can be measured is thus higher for O-rich stars than for C-rich stars. In both cases, a Li abundance determination can only be achieved ...
... line in C-stars is strong, that of the TiO molecule in oxygen-rich stars of the same effective temperature is even more severe. The lower limit of Li abundance that can be measured is thus higher for O-rich stars than for C-rich stars. In both cases, a Li abundance determination can only be achieved ...
The DBV stars: Progress and problems
... The effective temperature of GD 358 recently got updated; according to Beauchamp et al. (1995) it is, 25,300 f 300 K and log g = 7.85. Bradley & Winget (1994) indicated their mass determination was temperature dependent. I did some additional modeling and find the mass is closer to 0.58Ma and the he ...
... The effective temperature of GD 358 recently got updated; according to Beauchamp et al. (1995) it is, 25,300 f 300 K and log g = 7.85. Bradley & Winget (1994) indicated their mass determination was temperature dependent. I did some additional modeling and find the mass is closer to 0.58Ma and the he ...
Solar-type dynamo behaviour in fully convective stars without a
... level is reached at a Rossby number of approximately 0.13 ± 0.02 (ref. 9), corresponding to a rotation period that increases towards later spectral types, from 2 days for a star similar to the Sun to up to about 20 days for low-mass M dwarfs, and is also seen in both chromospheric emission and magn ...
... level is reached at a Rossby number of approximately 0.13 ± 0.02 (ref. 9), corresponding to a rotation period that increases towards later spectral types, from 2 days for a star similar to the Sun to up to about 20 days for low-mass M dwarfs, and is also seen in both chromospheric emission and magn ...
A n A n c i e n... How Astronomers Know the Vast Scale of Cosmic Time
... And what we learn from our instruments is that we live in a wonderful universe. No wonder astronomy has inspired artists and poets through the ages, from ancient Greece to today’s television series. Astronomy, the study of the universe, reveals a cosmos that is vast, varied, and beautiful. The sky i ...
... And what we learn from our instruments is that we live in a wonderful universe. No wonder astronomy has inspired artists and poets through the ages, from ancient Greece to today’s television series. Astronomy, the study of the universe, reveals a cosmos that is vast, varied, and beautiful. The sky i ...
Presentazione di PowerPoint
... Every channel map has been searched for emission above a conservative detection threshold (in the range 5-10 ) The detected maser spots have been fitted with two-dimensional elliptical Gaussians (intensities in the range: 0.3-17 Jy beam-1) A maser “feature” is considered real if it is detected in ...
... Every channel map has been searched for emission above a conservative detection threshold (in the range 5-10 ) The detected maser spots have been fitted with two-dimensional elliptical Gaussians (intensities in the range: 0.3-17 Jy beam-1) A maser “feature” is considered real if it is detected in ...
The Circumstellar Medium of Massive Stars in Motion
... Massive stars are the main drivers of the evolution of the gaseous component of galaxies. They emit huge quantities of far-ultraviolet photons that ionise and heat surrounding gas; their strong winds drive shocks and gas flows; and their final explosions as supernovae or gamma-ray bursts generate po ...
... Massive stars are the main drivers of the evolution of the gaseous component of galaxies. They emit huge quantities of far-ultraviolet photons that ionise and heat surrounding gas; their strong winds drive shocks and gas flows; and their final explosions as supernovae or gamma-ray bursts generate po ...
Hipparcos
Hipparcos was a scientific satellite of the European Space Agency (ESA), launched in 1989 and operated until 1993. It was the first space experiment devoted to precision astrometry, the accurate measurement of the positions of celestial objects on the sky. This permitted the accurate determination of proper motions and parallaxes of stars, allowing a determination of their distance and tangential velocity. When combined with radial-velocity measurements from spectroscopy, this pinpointed all six quantities needed to determine the motion of stars. The resulting Hipparcos Catalogue, a high-precision catalogue of more than 118,200 stars, was published in 1997. The lower-precision Tycho Catalogue of more than a million stars was published at the same time, while the enhanced Tycho-2 Catalogue of 2.5 million stars was published in 2000. Hipparcos ' follow-up mission, Gaia, was launched in 2013.The word ""Hipparcos"" is an acronym for High precision parallax collecting satellite and also a reference to the ancient Greek astronomer Hipparchus of Nicaea, who is noted for applications of trigonometry to astronomy and his discovery of the precession of the equinoxes.