A Method of Correcting Near-Infrared Spectra for Telluric Absorption
... standard,” whose intrinsic spectrum is known, to derive a system throughput curve that can then be applied to a target object spectrum observed nearby in the sky and close in time. Since T(l) varies with air mass and on timescales of the order of several to tens of minutes (depending on the atmosphe ...
... standard,” whose intrinsic spectrum is known, to derive a system throughput curve that can then be applied to a target object spectrum observed nearby in the sky and close in time. Since T(l) varies with air mass and on timescales of the order of several to tens of minutes (depending on the atmosphe ...
Discovery of White Dwarfs—1 Oct • Adams’ discovery
... – Practice test (with answers) is on the web. – Last 15min of class of Wed, Oct 8 will be Missouri club. ...
... – Practice test (with answers) is on the web. – Last 15min of class of Wed, Oct 8 will be Missouri club. ...
Debris disks: dynamics of small particles in
... with a radius ~55 AU, and a dust mass 5 x 10-4 Mearth • Thus it has at least ten times more mass than the Kuiper Belt ~10-5 Mearth • The only solar-type (age and spectral type) star with confirmed debris disk 850 μm ...
... with a radius ~55 AU, and a dust mass 5 x 10-4 Mearth • Thus it has at least ten times more mass than the Kuiper Belt ~10-5 Mearth • The only solar-type (age and spectral type) star with confirmed debris disk 850 μm ...
Foundations of Harappan Astronomy:
... 2) The movement of the moisture to the equatorial latitudes at Summer solstice (around March in the present epoch) 3) The amount of heating of the Indian subcontinental plate in early summer (around May – June in the present epoch) 4) The wind patterns in late summer (July to October in the present ...
... 2) The movement of the moisture to the equatorial latitudes at Summer solstice (around March in the present epoch) 3) The amount of heating of the Indian subcontinental plate in early summer (around May – June in the present epoch) 4) The wind patterns in late summer (July to October in the present ...
Magnitude. . . ?
... passing the whole electromagnetic spectrum), where Vega has some −0.3 mag. Thanks to this convention one needs not much care of which filter has been used indeed when reading popular texts. If e.g. the text reads that “the minor planet was of fifteenth brightness class”, i.e., that its faintness was ...
... passing the whole electromagnetic spectrum), where Vega has some −0.3 mag. Thanks to this convention one needs not much care of which filter has been used indeed when reading popular texts. If e.g. the text reads that “the minor planet was of fifteenth brightness class”, i.e., that its faintness was ...
Stellar Continua
... • Varies smoothly with changing temperature • Slope is negative (blue is brighter) for hot stars and positive (visual is brighter) for cooler stars • B-V works as a temperature indicator from 3500K to 9000K (but depends on metallicity) • For hotter stars, neutral H and H- opacities diminish, continu ...
... • Varies smoothly with changing temperature • Slope is negative (blue is brighter) for hot stars and positive (visual is brighter) for cooler stars • B-V works as a temperature indicator from 3500K to 9000K (but depends on metallicity) • For hotter stars, neutral H and H- opacities diminish, continu ...
MAGNITUDE AND COLOR SYSTEMS
... professional astronomers because there is not one magnitude system but instead several. For historical reasons within subfields, the definitions differ in two ways: (1) The spectral flux density can be expressed either as fν (ν) or fλ (λ). (2) The normalizing constant Q(i) differs among the systems; ...
... professional astronomers because there is not one magnitude system but instead several. For historical reasons within subfields, the definitions differ in two ways: (1) The spectral flux density can be expressed either as fν (ν) or fλ (λ). (2) The normalizing constant Q(i) differs among the systems; ...
interactive.hr.diagram
... To receive credit, you must answer in complete sentences! Don’t be afraid to think! 1) What is plotted along the horizontal axis of an H-R Diagram? ...
... To receive credit, you must answer in complete sentences! Don’t be afraid to think! 1) What is plotted along the horizontal axis of an H-R Diagram? ...
Project 3. Colour in Astronomy
... not a perfect vacuum. The interstellar medium (ISM) comprises cold neutral gas (H I at ≈ 70 K), warm neutral gas (H I at 6,000 K) and hot ionised plasma (H II at 10 6 K) primarily located in the plane of the galaxy in the spiral arms. Cosmic dust is made up of small grains of silicates, iron, carbon ...
... not a perfect vacuum. The interstellar medium (ISM) comprises cold neutral gas (H I at ≈ 70 K), warm neutral gas (H I at 6,000 K) and hot ionised plasma (H II at 10 6 K) primarily located in the plane of the galaxy in the spiral arms. Cosmic dust is made up of small grains of silicates, iron, carbon ...
Solutions for Midterm
... Answer as many of the following questions as you can. Full credit for this part is 90 points; any additional points you earn above this will be added as 30% bonus points (for a maximum of ...
... Answer as many of the following questions as you can. Full credit for this part is 90 points; any additional points you earn above this will be added as 30% bonus points (for a maximum of ...
Meilland
... Disk of Be stars (Delaa+ 2011, Meilland+ 2011, Smith+ 2012, Stee+2012) Disk and/or Wind of YSO (Peraut+ 2010, Benisty+ 2013) Interacting binary (Bonneau+ 2011) Wind of supergiants (Chesneau+ 2010) Peculiar stars (Mourard+ 2012) ...
... Disk of Be stars (Delaa+ 2011, Meilland+ 2011, Smith+ 2012, Stee+2012) Disk and/or Wind of YSO (Peraut+ 2010, Benisty+ 2013) Interacting binary (Bonneau+ 2011) Wind of supergiants (Chesneau+ 2010) Peculiar stars (Mourard+ 2012) ...
lect3 — 1 Measuring stars: What can be measured?
... stars tend to be somewhat variable, and their color doesn’t translate into luminosity quite so tightly as for something like the Sun. Cepheids: Classically, this is the most reliable stellar standard candle. This type of giant star is seen to have regular pulsations, and the pulsation period turns o ...
... stars tend to be somewhat variable, and their color doesn’t translate into luminosity quite so tightly as for something like the Sun. Cepheids: Classically, this is the most reliable stellar standard candle. This type of giant star is seen to have regular pulsations, and the pulsation period turns o ...
AST 443/PHY 517 Homework 1 Solutions
... 7. Determine the length of the semi-diurnal arc for each star. Which stars, if any, are circumpolar? At the right time of year (i.e., when it transits at local midnight), which star is observable for the longest uninterrupted time? See column (5) above. α Cen is circumpolar. The star visible for the ...
... 7. Determine the length of the semi-diurnal arc for each star. Which stars, if any, are circumpolar? At the right time of year (i.e., when it transits at local midnight), which star is observable for the longest uninterrupted time? See column (5) above. α Cen is circumpolar. The star visible for the ...
The professional project VEGA/CHARA and participation of ASPA
... With the following contribution I would like tell you something about the professional research project VEGA/CHARA. Although this project collaboration is not an open collaboration and the leader do not want to open it to people other than those who are already involved, they are very interested at ...
... With the following contribution I would like tell you something about the professional research project VEGA/CHARA. Although this project collaboration is not an open collaboration and the leader do not want to open it to people other than those who are already involved, they are very interested at ...
Issue 122 - Aug 2014
... you are by a significant, measurable amount. Over land, water is stored in lakes, rivers, aquifers, soil moisture, snow and glaciers. Even a change of just a few centimeters in the water table of an area can be clearly discerned by our best space-borne mission: NASA's twin Gravity Recovery and Clima ...
... you are by a significant, measurable amount. Over land, water is stored in lakes, rivers, aquifers, soil moisture, snow and glaciers. Even a change of just a few centimeters in the water table of an area can be clearly discerned by our best space-borne mission: NASA's twin Gravity Recovery and Clima ...
PS#3
... Lsun is 4x1026 W, so this is about 0.001 times the Sun’s luminosity 4. A radio transmitter on a spacecraft emits a signal at a frequency of 10 Hz. At Earth the signal is received and noted to be at 99,970,000Hz. How fast is the spacecraft moving? Is it receding or approaching? ...
... Lsun is 4x1026 W, so this is about 0.001 times the Sun’s luminosity 4. A radio transmitter on a spacecraft emits a signal at a frequency of 10 Hz. At Earth the signal is received and noted to be at 99,970,000Hz. How fast is the spacecraft moving? Is it receding or approaching? ...
Lecture 19 Brightness Units
... atoms in its transparent, slightly cooler, overlying atmosphere. Different stars show different absorption lines. Why? – Which spectral lines appear depends mainly on the temperature of the atmosphere. – The elemental composition of stars does not (usually) vary enough to make a big effect. ...
... atoms in its transparent, slightly cooler, overlying atmosphere. Different stars show different absorption lines. Why? – Which spectral lines appear depends mainly on the temperature of the atmosphere. – The elemental composition of stars does not (usually) vary enough to make a big effect. ...
Astro 210 Lecture 4 Sept. 4, 2013 Announcements: • PS 1 available
... to naked eye, in clear sky: about 6000 (!) stars visible over celestial sphere ⇒ about 3000 at any one night ...but this is just the “tip of the iceberg” directly measure flux Q: for old time’s sake, remind me–what is flux? ex: Sun: F⊙ = 1370 W m−2 Sirius (“dog star”) ...
... to naked eye, in clear sky: about 6000 (!) stars visible over celestial sphere ⇒ about 3000 at any one night ...but this is just the “tip of the iceberg” directly measure flux Q: for old time’s sake, remind me–what is flux? ex: Sun: F⊙ = 1370 W m−2 Sirius (“dog star”) ...
3.5-star-id
... Northern horizon • The Big Dipper (in Ursa Major) is the most easily recognized asterism (it’s not a constellation!) • Use it to find The Little Dipper (Ursa Minor), Polaris (Ursa Minor), Cassiopeia, Arcturus (Bootes), Vega (Lyra), Deneb (Cygus), Altair (Aquila). • Deneb is part of the asterism, Th ...
... Northern horizon • The Big Dipper (in Ursa Major) is the most easily recognized asterism (it’s not a constellation!) • Use it to find The Little Dipper (Ursa Minor), Polaris (Ursa Minor), Cassiopeia, Arcturus (Bootes), Vega (Lyra), Deneb (Cygus), Altair (Aquila). • Deneb is part of the asterism, Th ...
Absolute Magnitude - School
... closer the star is to us the brighter it will appear to be. The Absolute Magnitude (M) of a star is a measure of how luminous it actually is, or rather how bright it would appear to be from a certain distance compared with every other star at the same distance. M is defined as how bright a star woul ...
... closer the star is to us the brighter it will appear to be. The Absolute Magnitude (M) of a star is a measure of how luminous it actually is, or rather how bright it would appear to be from a certain distance compared with every other star at the same distance. M is defined as how bright a star woul ...
Monday, April 15
... • Then do the following Gedankenexperiment: – In your mind, put the star from its actual position to a position 10 pc away – If a star is actually closer than 10pc, its absolute magnitude will be a bigger number, i.e. it is intrinsically dimmer than it appears – If a star is farther than 10pc, its a ...
... • Then do the following Gedankenexperiment: – In your mind, put the star from its actual position to a position 10 pc away – If a star is actually closer than 10pc, its absolute magnitude will be a bigger number, i.e. it is intrinsically dimmer than it appears – If a star is farther than 10pc, its a ...
Monday, October 27
... • Then do the following Gedankenexperiment: – In your mind, put the star from its actual position to a position 10 pc away – If a star is actually closer than 10pc, its absolute magnitude will be a bigger number, i.e. it is intrinsically dimmer than it appears – If a star is farther than 10pc, its a ...
... • Then do the following Gedankenexperiment: – In your mind, put the star from its actual position to a position 10 pc away – If a star is actually closer than 10pc, its absolute magnitude will be a bigger number, i.e. it is intrinsically dimmer than it appears – If a star is farther than 10pc, its a ...
poster - arXiv
... modeling has shown that a planet produces an asymmetric resonant dust belt via resonances and gravitational scattering. This feature can serve as an indicator of an invisible outer planet. Our simulations have three main steps: 1. simulation of distribution of cometary population; 2. calculation of ...
... modeling has shown that a planet produces an asymmetric resonant dust belt via resonances and gravitational scattering. This feature can serve as an indicator of an invisible outer planet. Our simulations have three main steps: 1. simulation of distribution of cometary population; 2. calculation of ...
Vega
Vega (α Lyr, α Lyrae, Alpha Lyrae) is the brightest star in the constellation Lyra, the fifth brightest star in the night sky and the second brightest star in the northern celestial hemisphere, after Arcturus. It is a relatively close star at only 25 light-years from Earth, and, together with Arcturus and Sirius, one of the most luminous stars in the Sun's neighborhood.Vega has been extensively studied by astronomers, leading it to be termed ""arguably the next most important star in the sky after the Sun."" Vega was the northern pole star around 12,000 BCE and will be so again around the year 13,727 when the declination will be +86°14'. Vega was the first star other than the Sun to be photographed and the first to have its spectrum recorded. It was one of the first stars whose distance was estimated through parallax measurements. Vega has served as the baseline for calibrating the photometric brightness scale, and was one of the stars used to define the mean values for the UBV photometric system.Vega is only about a tenth of the age of the Sun, but since it is 2.1 times as massive its expected lifetime is also one tenth of that of the Sun; both stars are at present approaching the midpoint of their life expectancies. Vega has an unusually low abundance of the elements with a higher atomic number than that of helium. Vega is also a suspected variable star that may vary slightly in magnitude in a periodic manner. It is rotating rapidly with a velocity of 274 km/s at the equator. This is causing the equator to bulge outward because of centrifugal effects, and, as a result, there is a variation of temperature across the star's photosphere that reaches a maximum at the poles. From Earth, Vega is being observed from the direction of one of these poles.Based on an observed excess emission of infrared radiation, Vega appears to have a circumstellar disk of dust. This dust is likely to be the result of collisions between objects in an orbiting debris disk, which is analogous to the Kuiper belt in the Solar System. Stars that display an infrared excess because of dust emission are termed Vega-like stars.