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The white dwarf population within 40 pc of the Sun
The white dwarf population within 40 pc of the Sun

... photometry was only available for a subset of the SUPERBLINK catalog. Consequently, Limoges et al. (2015) use photometric data from other sources like 2MASS, Galex, and USNO-B1.0 – see Limoges et al. (2013) for details. It is unclear how this procedure may affect the observed sample. Obviously, simu ...
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... I NTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...
Intelligent Life in the Universe - e
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... One of the most exciting questions for mankind is whether we are alone in the universe. That intelligent nonhuman beings exist was commonly believed in prehistoric times as well as in antiquity. Creatures such as giants, centaurs, angels, and fairies were essential and universally accepted parts of ...
Venus Retrograde 2015: Love, Lust and War
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The white dwarf population within 40 pc of the Sun
The white dwarf population within 40 pc of the Sun

... northern hemisphere (δ > 0◦ ) up to a distance of 40 pc, and with proper motions larger than μ > 40 mas yr−1. Then, we introduced a cut in the reduced proper motion diagram (Hg , g − z) as Limoges et al. (2013) did – see their Fig. 1 – eliminating from the synthetic sample of white dwarfs those obje ...
Starwalk Manual En
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... With manual selection of location you can choose any place you like: Stockholm, Vienna, Sidney, or North Pole. You can observe the sky from wherever you like. After choosing the location you can explore the sky on your iPhone as if you were there physically. From the Menu choose Settings. Then tap o ...
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The phenomena of the satellites of the giant planets

... We do not intend to provide lessons on photometry: the reader will consult books specialized in this topic. However, we must say that, contrarily to astrometry, the purpose of which being to measure a position or a dimension either in kilometers or, more often, in angle units on the celestial sphere ...
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... is found to be on a collision course with Earth, so that an effort could be made to divert it. Currently, NASA carries out the “Spaceguard Survey” to find NEOs greater than 140 meters in diameter, and this program was budgeted at $4.1 million per year for FY 2006 through FY 2012. In chapter 7, we'll ...
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The white dwarf population within 40 pc of the Sun
The white dwarf population within 40 pc of the Sun

... atmospheric composition, and accurate measurements of their surface gravities and effective temperatures – are also needed. Over the last years, several model atmosphere grids with increasing levels of detail and sophistication have been released (Bergeron et al. 1992; Koester et al. 2001; Kowalski ...
New brown dwarfs and giant planets
New brown dwarfs and giant planets

... Several L dwarfs are wide companions of MS stars: e.g. Gl 584C, G196-3B, GJ1001B (& Gl229B in the past). What about L-dwarf/L-dwarf systems? - initial results suggest a higher frequency >30% for a > 3 AU (Koerner et al, 1999) - all known systems have equal luminosity --> implies equal mass Are binar ...
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The Sky This Month

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Science drivers for GLAO at LBT

... In Close et al (2007) there is the first derivation of “zones” of stability w.r.t. the mass and separation and formation cluster density of binary brown dwarfs. They show that most known wide binary brown dwarfs are young (open circles) and will likely be dissolved in their natal clusters before the ...
The accretion of Uranus and Neptune by collisions among planetary
The accretion of Uranus and Neptune by collisions among planetary

... that the former should/may have influenced the accretion process of the latter and (b) whatever mechanism allowed the formation of Jupiter (obviously not the presence of a pre-existing giant planet!), it did not work for Uranus and Neptune, otherwise they would have formed nearly at the same time as ...
ASTR 110 Lab Manual Sections M02 M03 M04
ASTR 110 Lab Manual Sections M02 M03 M04

... One special kind of relation is called a linear relation, where all of the data fall along a straight line in a graph like this. Carefully using a ruler, would you say that this relation is a linear relation? ...
A Recommendation - Amateur Astronomers, Inc.
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January 2014 Astronomy Calendar by Dave Mitsky Some

... The planet’s evening apparition ends when it reaches inferior conjunction on January 11, one synodic period after the transit of June 2012. Venus is located five degrees north of the Sun at that time. The brightest planet then enters the morning sky, becoming visible again on January 18th. Venus is ...
Asteroids - GEOCITIES.ws
Asteroids - GEOCITIES.ws

... officially known as 1 Ceres, Pallas as 2 Pallas, and so forth.) By mid-1991, more than 7,000 asteroids had been observed at two or more oppositions, and 5,000 of these were numbered. The discoverers have the right to choose a name for their discoveries as soon as they are numbered. Now the names sel ...
Observing Uranus and its satellites (2006
Observing Uranus and its satellites (2006

... At the beginning of the 21st century amateur astronomers in increasing numbers started digital imaging of the planets using webcams and other cameras. In the beginning Jupiter, Saturn and ...
Planet Formation: Disk Formation and Evolution
Planet Formation: Disk Formation and Evolution

... scenarios. The planets (major and minor) reside in the same plane and are relatively regularly space; they all orbit the Sun in the same direction; most planets spin in the same direction in which they orbit the Sun; and orbital periods increase with distance from the Sun. We also see a range of dyn ...
Alpha Centauri
Alpha Centauri

... Never viewed from northern latitudes(around 40 degrees)  Traveling south below the earths surface, across the equator you will see it. ...
The Secular and Rotational Brightness Variations of Neptune
The Secular and Rotational Brightness Variations of Neptune

... This is the seventh paper in a series which models the brightness, color and albedo of all the planets except Earth on the Johnson-Cousins magnitude system. Mercury (Mallama et al. 2002) and Venus (Mallama et al. 2006) were observed with the Solar and Heliospheric Observatory satellite. The SOHO mag ...
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Icarus Origin of the structure of the Kuiper belt during a... orbits of Uranus and Neptune

... with smaller q, then a correlation between color and perihelion distance becomes apparent (gray color objects becoming more abundant at low q). (vii) The existence of the extended scattered disk, which consists of stable non-resonant objects with semi-major axes beyond Neptune’s 1:2 MMR and mainly h ...
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Definition of planet



The definition of planet, since the word was coined by the ancient Greeks, has included within its scope a wide range of celestial bodies. Greek astronomers employed the term asteres planetai (ἀστέρες πλανῆται), ""wandering stars"", for star-like objects which apparently moved over the sky. Over the millennia, the term has included a variety of different objects, from the Sun and the Moon to satellites and asteroids.By the end of the 19th century the word planet, though it had yet to be defined, had become a working term applied only to a small set of objects in the Solar System. After 1992, however, astronomers began to discover many additional objects beyond the orbit of Neptune, as well as hundreds of objects orbiting other stars. These discoveries not only increased the number of potential planets, but also expanded their variety and peculiarity. Some were nearly large enough to be stars, while others were smaller than Earth's moon. These discoveries challenged long-perceived notions of what a planet could be.The issue of a clear definition for planet came to a head in 2005 with the discovery of the trans-Neptunian object Eris, a body more massive than the smallest then-accepted planet, Pluto. In its 2006 response, the International Astronomical Union (IAU), recognised by astronomers as the world body responsible for resolving issues of nomenclature, released its decision on the matter. This definition, which applies only to the Solar System, states that a planet is a body that orbits the Sun, is massive enough for its own gravity to make it round, and has ""cleared its neighbourhood"" of smaller objects around its orbit. Under this new definition, Pluto and the other trans-Neptunian objects do not qualify as planets. The IAU's decision has not resolved all controversies, and while many scientists have accepted the definition, some in the astronomical community have rejected it outright.
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