Sources/First astronomical sources
In the context of radiation astronomy, the first astronomical source may not have been from the sky.
Hominins are intelligent life forms on Earth. It may be true that hominins seldom pay attention to those things that seldom affect them in a harmful way, or that are not edible, do not provide or are not useful for shelter, or have little positive effect on health and well-being.
Curiosity may make everything something to pay attention to.
Source astronomy has its origins in the actions of intelligent life on Earth when they noticed things or entities falling from above and became aware of the sky.
Def. the point of origin of a ray, beam, or stream of small cross section traveling in a line is called a radiation source.
Is the sky a radiation source or an obstruction or interference between the observer and a source?
The same question may be asked when looking downward at the Earth's crust, regolith, or water below the observer.
The sky may have been thought of at one time as impenetrable. The same assumption may have occurred regarding the Earth below.
In the context of radiation astronomy, the first astronomical source may not have been from the sky. Sources of gamma radiation exist within the Earth's crust. While these may not seem like astronomical gamma-ray sources, cosmic rays penetrating the sky, impinging on the rocks on the Earth's surface may give off gamma-rays. Radiation traveling through the Earth toward the surface from beneath may also generate gamma rays.
Early craters that may have an astronomical origin need to have artifacts that are unique to this origin.
At right is a geologic clock representation. It shows some of the major units of geological time and definitive events of Earth history. The Hadean eon represents the time before fossil record of life on Earth; its upper boundary is now regarded as 4.0 Ga (billion years ago). Other subdivisions reflect the evolution of life; the Archean and Proterozoic are both eons, the Palaeozoic, Mesozoic and Cenozoic are eras of the Phanerozoic eon. The two million year Quaternary period, the time of recognizable humans, is too small to be visible at this scale.
The following four timelines show the geologic time scale. The first shows the entire time from the formation of the Earth to the present, but this compresses the most recent eon. Therefore the second scale shows the most recent eon with an expanded scale. The second scale compresses the most recent era, so the most recent era is expanded in the third scale. Since the Quaternary is a very short period with short epochs, it is further expanded in the fourth scale. The second, third, and fourth timelines are therefore each subsections of their preceding timeline as indicated by asterisks. The Holocene (the latest epoch) is too small to be shown clearly on the third timeline on the right, another reason for expanding the fourth scale. The Pleistocene (P) epoch. Q stands for the Quaternary period.
The sky, also known as the celestial dome, commonly refers to everything that lies a certain distance above the surface of Earth, including the atmosphere and the rest of outer space. In the field of astronomy, the sky is also called the celestial sphere. This is an imaginary dome where the sun, stars, planets, and the moon are seen to be traveling. The celestial sphere is divided into regions called constellations. Usually, the term sky is used from the point of view of the Earth's surface. However, the exact meaning of the term can vary; in some cases, the sky is defined as only the denser portions of the atmosphere, for example.
Searching for the first astronomical source, or the first one per constellation, requires determining the exact boundaries of each constellation. There are 88 modern constellations that the International Astronomical Union (IAU) has used to divide the celestial sphere into 89 irregularly shaped boxes. The constellation Serpens is split into two separate sections, Serpens Caput (the snake's head) to the west and Serpens Cauda (the snake's tail) to the east.
Sources recorded to ancient constellations need to be translated to current coordinates and constellations.
Using detectors placed in the Earth, on Earth, or above the Earth's atmosphere, various emanations have been detected incoming from each of these constellations, whether through the Earth or not. Each area of the celestial sphere may have at least one source detected.
Def. an action or process of throwing or sending out a traveling ray in a line, beam, or stream of small cross section is called radiation.
Rays may have a temporal, spectral, or spatial distribution.
They may also be dependent on other variables as yet unknown.
Particle radiation consists of a stream of charged or neutral particles, from the size of subatomic elementary particles upwards of rocky and gaseous objects to even larger more loosely bound entities. All of these are within the field of radiation astronomy.
"The outbursts of novae have been recorded for over 2000 years (for an historical review, see Duerbeck 2008)."
"It was only in the 1920s during the “Great Debate” that it was realised that “ordinary” novae such as T Aur (1892 - often seen as the first well-studied nova outburst) were very distinct from “supernovae” such as S And (1885 - in M31)."
"Later, Dwarf Novae (DNe) and Classical Novae (CNe) were in turn recognised as rather different beasts and certain of the Classical Novae were also subsequently reclassified as Recurrent Novae (RNe) when a second major outburst was recorded (the earliest example being T Pyx with the 1902 outburst repeating that first noted for this object in 1890)."
"The existence of a constant bolometric phase of post-outburst development was first proposed following multifrequency observations of FH Ser (1970 - see e.g. Gallagher & Starrfield 1976). The initial optical decline is then due to a redistribution of flux to shorter wavelengths due to a decreasing mass-loss rate giving rise to a shrinkage of the effective (pseudo)photosphere at constant bolometric luminosity as steady nuclear burning continues on the WD surface."
"V1974 Cyg was also the first nova to be observed with HST (Paresce et al. 1995; Krautter et al. 2002 - see Fig. 3) beginning 467 days after outburst."
"RS Oph has had recorded outbursts in 1898, 1933, 1958,1967, 1985 and 2006, plus probable eruptions in 1907 and 1945. The optical behaviour from one outburst to the next is very similar. The central system comprises a high mass WD in a 455 day orbit with a red giant (M2III) and d (= 1.6±0.3 kpc) and NH (= 2.4 ± 0.6 x 1021 cm−2) are well defined (see Evans et al. 2008, and papers therein)."
"The 1985 outburst was the first to be observed beyond the visual but it was only with the latest eruption on 2006 February 12 that very detailed radio imagery and X-ray observations in particular could be performed."
"The [initial discovery of an infrared point source at 2.2 µ by Becklin and Neugebauer (1967)] BN source is also the first astronomical source for which polarization has been detected in the 8- to 14-µ part of the spectrum (Dyck et al. 1973)."
Around 150 AD, the Hellenistic astronomer Claudius Ptolemy described Sirius as reddish, along with five other stars, Betelgeuse, Antares, Aldebaran, Arcturus and Pollux, all of which are clearly of orange or red hue. The discrepancy was first noted by amateur astronomer Thomas Barker, who prepared a paper and spoke at a meeting of the Royal Society in London in 1760. The existence of other stars changing in brightness gave credence to the idea that some may change in colour too; Sir John Herschel noted this in 1839, possibly influenced by witnessing Eta Carinae two years earlier. Thomas Jefferson Jackson See resurrected discussion on red Sirius with the publication of several papers in 1892, and a final summary in 1926. He cited not only Ptolemy but also the poet Aratus, the orator Cicero, and general Germanicus as colouring the star red, though acknowledging that none of the latter three authors were astronomers, the last two merely translating Aratus' poem Phaenomena. Seneca, too, had described Sirius as being of a deeper red colour than Mars. However, not all ancient observers saw Sirius as red. The 1st century AD poet Marcus Manilius described it as "sea-blue", as did the 4th century Avienus. It is the standard star for the color white in ancient China, and multiple records from the 2nd century BC up to the 7th century AD all describe Sirius as white in hue.
In 1985, German astronomers Wolfhard Schlosser and Werner Bergmann published an account of an 8th century Lombardic manuscript, which contains De cursu stellarum ratio by St. Gregory of Tours. The Latin text taught readers how to determine the times of nighttime prayers from positions of the stars, and Sirius is described within as rubeola — "reddish". The authors proposed this was further evidence Sirius B had been a red giant at the time.
"The first aluminum-bearing mineral to form in C-star circumstellar shells is AlN (Lodders & Fegley 1999). ... if an absorption or emission feature in an astronomical source were to coincide with 14.1 µm, AlN would be among the list of other possible carriers (e.g. C2H2). One question is whether or not AlN would survive long enough to be detected. As the temperature decreases, AlN may quickly transform to corundum (Al2O3; fig. 6e, Lodders & Fegley 1995)."
Theory of first sources
"We now assume that the γ-rays are produced [from 3C 279] by relativistic electrons via Compton scattering of synchrotron photons (SSC). In any such model, the fact that the γ-rays luminosity, produced via Compton scattering, is higher than that emitted at lower frequencies (1014 - 1016 Hz), supposedly via the synchrotron process, implies a radiation energy density, Ur, higher than the magnetic energy density, UB. From the observed power ratio we derive that Ur must be one order of magnitude greater than UB, which may be a lower limit if Klein-Nishina effects reduce the efficiency of the self-Compton emission. This result is independent of the degree of beaming, which, for a homogeneous source, affects both the synchrotron and the self-Compton fluxes in the same way. This source is therefore the first observed case of the result of a Compton catastrophe (Hoyle, Burbidge, & Sargent 1966)."
"It is generally believed that stellar complexes appear to be the result of the evolution of gaseous superclouds which are the largest in size and mass (up to ~107 M⊙), entities of diffuse matter distributed in the galactic disks. The “top-down” mechanism of gravitational instability assumes that these [gaseous] superclouds are the first entities formed whereas the denser star-forming clouds are developing inside them [...] The "top-down" scenario implies the presence of a few fundamental scales of stellar groupings and the hierarchical arrangement of the developed structures."
The "many other types of radio sources in our galaxy [...] include so-called radio stars, emission nebula, flare stars and pulsars. [...] Pulsars were first discovered in 1967 by Cambridge post-graduate student Jocelyn Bell as she processed charts associated with an unrelated project to study twinkling radio sources. She noticed recurrent signals when the antenna was pointed in a certain direction. Further study revealed a precise timing interval of about 1 second. It also was found that the pulses were dispersed such that the lower frequencies arrived later than the higher frequencies. This dispersion could be attributed to scattering of the radiation by interstellar electrons and, if so, could provide an indication of the pulsar distance."
"Quasars, or quasi-stars (also 'quasi-stellar radio' source) are unusual radio sources (right, source NRAO). According to Hey they were discovered in 1963. The first quasar was found by collaboration with an optical observatory. The position of a radio source coincided with an unusual blue star whose spectral lines were unrecognizable. Further investigations showed the object actually was a double-source, one of which coincided with the blue star. The other source had a faint jet associated with it. It was determined that the spectral lines indicated a very distant source. Of great interest was the conclusion that these quasars emitted radio powers comparable to the strong radio galaxies."
"How small were the first cosmological objects?"
"The minimum [baryonic] mass [Mb] that a virialized gas cloud must have in order to be able to cool in a Hubble time [...] is found to be strongly redshift dependent, dropping from 106 M⊙ at z ~ 15 to 5 x 103 M⊙ at z ~ 100 as molecular cooling becomes effective. For z > 100, Mb rises again, as cosmic microwave background photons inhibit H2-formation through the H- channel. Finally, for z ≫ 200, the -channel for H2 formation becomes effective, driving Mb down toward Mb ~ 103 M⊙. With a standard cold dark matter power spectrum with σ8 = 0.7, this implies that a fraction 10-3 of all baryons may have formed luminous objects by z = 30, which could be sufficient to reheat the universe."
A "new type of neutron star model (Q stars) [is such that] high-density, electrically neutral baryonic matter is a coherent classical solution to an effective field theory of strong forces and is bound in the absence of gravity. [...] allows massive compact objects, [...] and has no macroscopic minimum mass."
"Compact objects in astronomy are usually analyzed in terms of theoretical characteristics of neutron stars or black holes that are based upon calculations of equations of state for matter at very high densities. At such high densities, the effects of strong forces cannot be neglected. There are several conventional approaches to describing nuclear forces, all of which find that for a baryon number greater than ~250, a nucleus will become energetically unbound. High-density hadronic matter is not stable in these theories until there are enough baryons for gravitational binding to form a neutron star, typically with a minimum mass ≳ 0.1 M⊙ and maximum mass ≲ 3 M⊙."
"Another possibility [called "baryon matter"] is that in the absence of gravity high-density baryonic matter is bound by purely strong forces. [...] nongravitationally bound bulk hadronic matter is consistent with nuclear physics data [...] and low-energy strong interaction data [...] The effective field theory approach has many successes in nuclear physics [...] suggesting that bulk hadronic matter is just as likely to be a correct description of matter at high densities as conventional, unbound hadronic matter."
"The idea behind baryon matter is that a macroscopic state may exist in which a smaller effective baryon mass inside some region makes the state energetically favored over free particles. [...] This state will appear in the limit of large baryon number as an electrically neutral coherent bound state of neutrons, protons, and electrons in β-decay equilibrium."
"Electromagnetic expulsion acts on a body submerged in a conducting fluid traversed by an electric current and a magnetic field (provided the Lorentz force in the vicinity of the body is not zero). The effect results from the difference of electric conductivities inside and outside the body and is the [ magnetohydrodynamics ] MHD counterpart of the Archimedean force. [...] The consequences of electromagnetic expulsion are shown to be observable in solar prominences; here it can balance the gravity and can generate fast vortex flows inside them and in their vicinity,"
Let "an inhomogeneity [be] created by changing the electric conductivity of a volume element. Then such simple equilibrium will be destroyed and a surface force will act upon the volume (Kolin 1953). This force is a result of pressure difference created by difference in the Lorentz force inside and outside the volume. In this sense, the surface force is analogous to the Archimedaen one and can be termed the 'electromagnetic expulsion' force. [...] the force [...] arises owing to inhomogeneity of electric conductivity of the fluid rather than its density. Hence the electromagnetic expulsion is quite different from the 'magnetic buoyancy' (Parker 1955) in that the former occurs even in the absence of gravity."
"The first to theoretically investigate the phenomenon of electromagnetic expulsion were Leenov and Kolin (1954)."
"They showed that it is possible to exert forces by electromagnetic means upon bodies submerged in a conducting fluid if their conductivity σ1 differs from that of the fluid σ0. A body plunged into the fluid is acted upon by the force"
"Here the first term on the right side describes the ordinary Archimedean force. It equals zero if ρ1 = ρ0. The second term corresponds to the electromagnetic expulsion force."
X-ray continuum emission can arise both from a jet and from the hot corona of the accretion disc via a scattering process: in both cases it shows a power-law spectrum. In some radio-quiet [active galactic nuclei] AGN there is an excess of soft X-ray emission in addition to the power-law component.
The X-ray continuum can arise from bremsstrahlung, black-body radiation, synchrotron radiation, or what is called inverse Compton scattering of lower-energy photons by relativistic electrons, knock-on collisions of fast protons with atomic electrons, and atomic recombination, with or without additional electron transitions.
Karl "Jansky accidently discovered the galactic background radiation in 1932 while studying the arrival directions of atmospheric noise using a very unusual antenna".
Determining the first meteor source probably depends on determining the first meteor.
Meteors may occur in showers, which arise when the Earth passes through a trail of debris left by a comet, or as "random" or "sporadic" meteors, not associated with a specific single cause. A number of specific meteors have been observed, largely by members of the public and largely by accident, but with enough detail that orbits of the meteoroids producing the meteors have been calculated. All of the orbits passed through the asteroid belt.
"[A]rchival research [confirms] the presence of an ancient planetary nebula (PN), with an apparent hourglass morphology, ejected by the nova in a previous phase of evolution and into which the nova ejecta are now running."
Some low energy cosmic rays originate or are associated with solar flares. Even these cosmic rays have too high an energy to originate from the solar photosphere. The coronal cloud in close proximity to the Sun may be a source or create them as it bombards the chromosphere from above.
"In particular we recognize a first trace of Vela, brightest gamma and radio galactic source, and smeared sources along Galactic Plane and Center [as a source of ultra high energy cosmic rays (UHECR)]."
"The main correlated map is the 408 MHz one. The first astronomical source that seem to correlate is the main multiplet along CenA. This AGN source, the nearest extragalactic one, sits in the same direction of a far Centaurus Cluster (part of the Super-Galactic Plane). The blurring by random galactic magnetic field might spread the nearest AGN event along the same Super-Galactic Plane, explaining the AUGER group miss-understanding ."
"Energetic neutral atoms (ENA), emitted from the magnetosphere with energies of ∼50 keV, have been measured with solid-state detectors on the IMP 7/8 and ISEE 1 spacecraft. The ENA are produced when singly charged trapped ions collide with the exospheric neutral hydrogen geocorona and the energetic ions are neutralized by charge exchange."
"The IMAGE mission ... High Energy Neutral Atom imager (HENA) ... images [ENAs] at energies between 10 and 60 keV/nucleon [to] reveal the distribution and the evolution of energetic [ions, including protons] as they are injected into the ring current during geomagnetic storms, drift about the Earth on both open and closed drift paths, and decay through charge exchange to pre‐storm levels."
"In 2009, NASA's Interstellar Boundary Explorer (IBEX) mission science team constructed the first-ever all-sky map [at right] of the interactions occurring at the edge of the solar system, where the sun's influence diminishes and interacts with the interstellar medium. A 2013 paper provides a new explanation for a giant ribbon of energetic neutral atoms – shown here in light green and blue -- streaming in from that boundary."
"[T]he boundary at the edge of our heliosphere where material streaming out from the sun interacts with the galactic material ... emits no light and no conventional telescope can see it. However, particles from inside the solar system bounce off this boundary and neutral atoms from that collision stream inward. Those particles can be observed by instruments on NASA’s Interstellar Boundary Explorer (IBEX). Since those atoms act as fingerprints for the boundary from which they came, IBEX can map that boundary in a way never before done. In 2009, IBEX saw something in that map that no one could explain: a vast ribbon dancing across this boundary that produced many more energetic neutral atoms than the surrounding areas."
""What we are learning with IBEX is that the interaction between the sun's magnetic fields and the galactic magnetic field is much more complicated than we previously thought," says Eric Christian, the mission scientist for IBEX at NASA's Goddard Space Flight Center in Greenbelt, Md. "By modifying an earlier model, this paper provides the best explanation so far for the ribbon IBEX is seeing.""
"The third largest solar proton event in the past thirty years took place during July 14-16, 2000, and had a significant impact on the earth's atmosphere."
"Beta-particles leaving the upper surface of the lunar sample could trigger the upper beta detector, while the lower beta-detector was triggered by beta particles from the lower surface of the sample."
"The suprathermal electrons in the solar wind and in solar particle events have excellent properties for this application: they move rapidly, they remain tightly bound to their field lines, and they may arrive "scatter-free" even at low energies, and from deep in the solar atmosphere (Lin 1985)."
During solar flares “[s]everal radioactive nuclei that emit positrons are also produced; [which] slow down and annihilate in flight with the emission of two 511 keV photons or form positronium with the emission of either a three gamma continuum (each photon < 511 keV) or two 511 keV photons."
"A few hours later, ANTARES looked up at the sky for the first time and caught sight of its first muons."
Gamma-ray bursts (GRBs) are flashes of gamma rays associated with extremely energetic explosions that have been observed in distant galaxies. They are the most luminous electromagnetic events known to occur in the universe. Bursts can last from ten milliseconds to several minutes, although a typical burst lasts 20–40 seconds. The initial burst is usually followed by a longer-lived "afterglow" emitted at longer wavelengths (X-ray, ultraviolet, optical, infrared, microwave and radio).
The high temperature of the coronal cloud gives it unusual spectral features. These features have been traced to highly ionized atoms of elements such as iron which indicate a plasma's temperature in excess of 106 K (MK) and associated emission of X-rays.
"The Sun had been the first astronomical source of X-rays to be discovered, although it was in fact a comparatively weak source. Its face, being at a temperature of only a few thousand degrees, did not produce X-rays at all. The solar corona, especially around active regions of the Sun’s surface, reached much higher temperatures than the surface itself, because of its continual bombardment by the solar wind, and was entirely responsible for the few X-rays that the Sun did emit."
The "puddles of X-ray emission seen around the centres of galaxies were not the only diffuse X-ray sources. Around the galaxy clusters in Virgo and Coma, puddles measuring nearly 3° across could be seen, and other, more distant, galaxy clusters were accompanied by similar, smaller halos. The familiar optical images of these clusters revealed that they typically contained hundreds to thousands of galaxies, spread over tens of millions of light years, but the X-ray emission showed that there was also some smooth distribution of material in between the galaxies – an intergalactic medium. The significance of its X-ray emission was that for the first time, the amount of gas lying in the vast spaces between galaxies could be estimated, and surprisingly, it seemed that there was ten times as much invisible gas between galaxies as there was within them. This gas was understood to have reached temperatures of tens of millions of degrees in the process of falling in towards the immense gravitational attraction of the galaxy cluster, and hence to have become a source of X-rays."
Super soft X-ray sources
Acquiring a suntan may be a student's first encounter with an astronomical ultraviolet source. This probably occurs at the secondary level.
"The color of a star, as determined by the peak frequency of the visible light, depends on the temperature of the star's outer layers, including its photosphere. The effective temperature of the surface of the Sun's photosphere is 5,778 K. That's a peak emittance wavelength of 501.5 nm (~0.5 eV) making the photosphere a primarily green radiation source. The temperature of the photosphere is way too cool to generate appreciable amounts of ultraviolet. In fact, the Sun's photosphere probably generates little or no ultraviolet rays.
The transition region is visible in far-ultraviolet (FUV) images from the TRACE spacecraft, as a faint nimbus above the dark (in FUV) surface of the Sun and the corona. The nimbus also surrounds FUV-dark features such as solar prominences, which consist of condensed material that is suspended at coronal altitudes by the magnetic field.
"This is the first astronomical source observed by the Extreme Ultraviolet Explorer (EUVE) in its calibration phase and is source EUVE 1257 + 220 in the EUVE".
"Gyro-synchrotron emission from the material moving at semi-relativistic velocity in the jets is a mechanism which can produce UV radiation with properties consistent with all the observations. SS433 would then be the first astronomical source known to emit gyro-synchrotron radiation at non-radio frequencies."
At right is a set of images from different years for Neptune. These images "show that Neptune's brightness has increased significantly since 1996. The rise is due to an increase in the amount of clouds observed in the planet's southern hemisphere. These increases may be due to seasonal changes caused by a variation in solar heating. Because Neptune's rotation axis is inclined 29 degrees to its orbital plane, it is subject to seasonal solar heating during its 164.8-year orbit of the Sun. This seasonal variation is 900 times smaller than experienced by Earth because Neptune is much farther from the Sun. The rate of seasonal change also is much slower because Neptune takes 165 years to orbit the Sun. So, springtime in the southern hemisphere will last for several decades! Remarkably, this is evidence that Neptune is responding to the weak radiation from the Sun. These images were taken in visible and near-infrared light by Hubble's Wide Field and Planetary Camera 2."
"According to Gruson and Brugsch the Egyptians were acquainted with, and even worshipped, the zodiacal light from the very earliest times, as a phenomenon visible throughout the East before sunrise and after sunset. It was described as a glowing sheaf or luminous pyramid perpendicular to the horizon in summer, and inclined more or less during the winter. Indeed the Egyptians represented the zodiacal light under the form of a triangle which sometimes stood upright and at other times was inclined."
"[T]he notions of mantis [/Kaggen or Cagn ]and moon worship [by the Nharo, Bushmen, or San people] were European fabrications". Cagn is said to have created the moon. But, if these gods are European fabrications either by the San people for the Europeans, or by the Europeans of the San, then it may be unlikely that /Kaggen created the Moon. Or, perhaps that the Mantis created the Moon but neither, nor the Sun, are or were worshipped by the San.
The Moon is one candidate for the first visual source. A source that may have been created within the memory of the hominins.
Violet photographs of the planet Venus taken in 1927 “recorded two nebulous bright streaks, or bands, running ... approximately at right angles to the terminator” that may be from the upper atmosphere.
The "earliest known astronomy anywhere in the world [is] that of the Australian Aborigines, whose culture has existed for some 40,000 years".
"The Aranda tribes of Central Australia, for example, distinguish red stars from white, blue and yellow stars."
“The distribution of the high-latitude faint blue stars over Teff ... [shows] that the principal sequence [has] two gaps, at colors corresponding to log Teff ~ 4.11 (gap 1) and log Teff ~ 4.33 (gap 2). ... [T]he gaps [may be] a horizontal-branch phenomenon. ... [C]urrent theoretical concepts of the advanced evolution of Population II stars can explain the majority of blue halo stars.”
Stellar classification places the range of effective surface temperatures for conventional color blue, bluish, or blue white stars as the class K stars as class O ≥33,000 K blue, 10,000-33,000 K blue to blue white, and 7,500-10,000 K to white, or white to blue white (apparent color).
* Not a standard star.
Both Luna 24 and Apollo 12 soil samples are from mare soils that reflect primarily cyan that is likely due to the presence of TiO2 in the soils.
The iron (Fe XIV) green line has been observed in the plasma of the coronal cloud about the Sun.
"Carroll and McCormack (1972) in Dublin reported complex spectra in the blue and green wavelength regions of both FeH and FeD".
During the limb flares of December 18, 1956, a coronal line at 569.4 nm, a yellow line, occurred at 1822 UTC, 1900 UTC, undiminished up to 20,000 km above the solar limb, and at 2226 UTC, is identified as Ca XV. "The coronal temperature was 4000000°." "The December 18, 1956, flare appears to have been a violent condensation of material from a dense coronal cloud above an active region."
The first yellow source in Aquila is unknown.
"It is well known that [β Aquilae] has sensibly diminished in brightness within memory of persons living; but no change has taken place in this respect for many years past, nor is there any reason to suppose that it was ever brighter than γ [Aquilae]. ... Flamsteed rated β Aquilae as 3 1/2; whilst Hevelius, remarkably enough, estimated it as only (what it is now) the fourth, although later observers reckoned it, like Flamsteed, of the 3 1/2 magnitude."
In 1908, β Aql is listed as a spectral class K II with a suspected period of variability of two months.
In 1922, "The variable and comparison stars are, in the Harvard system, ... . H.R. 7602, β Aquilae, magnitude 3.90, spectrum K. The Mt. Wilson spectral types are ... β Aquilae, G7." "[T]oward the end of the series [of observations] β Aquilae was fainter than at the beginning."
Since 1943, the spectrum of this star Alshain (Beta Aquilae) has served as one of the stable anchor points by which other stars are classified. But, "The Atlas of Stellar Spectra was published fifty years ago by W.W. Morgan, P.C. Keenan, and E. Kellman(1943). Since then, there have been supplementary lists of standard stars and atlases published by Morgan and/or Keenan in 1953, 1973, 1976, and 1978. In these later publications, some of the types for the standard stars were modified in the light of better data."
In 1953, β Aql is listed as the standard star for G8 IV. A G8 IV is a yellow (or orange-yellow) star.
Beta Aquilae on 21 March 2012 at 16:35 in the Wikipedia article "Beta Aquilae", does not include the word "yellow" in the text but by the star classification and spectral type G8 IVvar in the Starbox it is a yellow star.
The variability of BD +50 961 (SY Persei, an orange star) is confirmed.
"From col. iv, lines 2-3, we have Saturn in Pisces and Jupiter in Cancer on August 1. Tuckerman's tablesd show that this configuration occurred in A.D. 21-22, and thereafter at intervals of roughly 59 years."
"Ideally all intrinsic colours should be found from unreddened stars. This is possible for dwarf and giant stars later than about A0 (Johnson, 1964) ... However, it cannot be used for stars of other spectral classes since they are all relatively infrequent in space, and generally reddened."
"Spectra from the Voyager I IRIS experiment confirm the existence of enhanced infrared emission near Jupiter's north magnetic pole in March 1979."
"[F]or wavelengths between 0.35 and 0.45 mm ... the radiances can be matched by models which include NH3 ice particles which are between 30 and 100 µm in size, regardless of the scale height characterizing the cloud."
The first detection of nonflare microwave emission from the coronae of single late-type dwarf stars has been reported.
In 1955, Bernard Burke and Kenneth Franklin detected bursts of radio signals coming from Jupiter at 22.2 MHz. The period of these bursts matched the rotation of the planet, and they were also able to use this information to refine the rotation rate. Radio bursts from Jupiter were found to come in two forms: long bursts (or L-bursts) lasting up to several seconds, and short bursts (or S-bursts) that had a duration of less than a hundredth of a second.
"It would have been difficult to imagine the wonders that would later be revealed when Karl Jansky identified the first astronomical source of radio waves."
"The existence of superluminal energy transfer has not been established so far, and one may ask why. There is the possibility that superluminal quanta just do not exist, the vacuum speed of light being the definitive upper bound. There is another explanation, the interaction of superluminal radiation with matter is very small, the quotient of tachyonic and electric fine-structure constants being q2/e2 ≈ 1.4 x 10-11 , and therefore superluminal quanta are hard to detect."
"The very fast neon nova GK Persei rivalled the brightness of Vega at the peak of its outburst in 1901 (see Bode, O’Brien & Simpson 1994, and references therein). Early observations showed it to possess optical nebulosities on arcminute scales apparently expanding at super-light velocities and subsequently explained as light echoes (Kapteyn 1902). Indeed, it was the first astronomical source in which such motion was observed and one of only three novae where such an effect has been noted (the other two being V732 Sgr (Swope 1940) and V1974 Cyg (Casalegno et al. 2000) - see next section)."
"The 1901 nova outburst was therefore the first of ultimately very many that this system will undergo."
"The classical nova GK Persei ... has turned out to be the longest lived and most energetic among the classical novae and appears more like a supernova remnant (SNR) in miniature but evolving on human timescales."
"The object 3C 279 is a "typical" blazar with a compact, variable, flat-spectrum radio core and a highly polarized and violently variable optical continuum. It was the first source discovered to show superluminal expansion (Whitney et al. 1971)."
"A best-fit calculation mixed with atoms and molecules confirmed the first discovery of bands in the UV meteor [2001 Leonid fireball at 18:58:20 UT on 2001 November 18] spectrum. The temperature was estimated to be 10,000 K with a low number density of 1.55 x 105 cm−3. Such unexpectedly strong ultraviolet emission, in particular for (1,0) at 353.4 nm, is supposed to be formed through the wide dimensions of high-temperature regions caused by a large meteoroid."
"Jenniskens, & Laux (2004a) found excessive emissions between 770 and 840 nm with the maximums centered at ~789 and ~815 nm, which could be caused by the “first negative A–X” band of the molecular nitrogen ion Meinel bands. The evidence of a Meinel system was identified in two fireballs (with magnitudes of – 1 and – 7) obtained during the Leonid meteor shower in 2001 and 2002 Leonid Multi-Instrument Aircraft Campaign (MAC; (Jenniskens 2002a). Because their unintensified slitless CCD spectrograph could provide a high spectral resolution with the precise determination of wavelength in the near-IR region, these must be reliable findings."
"The D type asteroids are among the darkest objects known in our solar system. Here, we present infrared spectra of one of the main-belt D type asteroids, 773 Irmintraud. In contrast to previous observations of D type asteroids, we found a gap of reflectance around 3 µm in wavelength. The 3 µm gap is one of the spectral signatures of OH or H2O as water ice or in hydrous minerals, which had formed in the processes of aqueous alteration in the early solar system."
"A number of low-albedo asteroids have spectra indicating the presence of the broad absorption around 3 µm [e.g., Jones et al., 1990]. This absorption is sometimes a combination of a sharp 2.7-µm feature due to structural OH ions and a much broader 2.9 µm absorption due to interlayer H2O molecules in hydrous minerals, and the possible 3.1 µm water ice feature [e.g., Lebofsky et al., 1981]."
"The 3 µm band is, however, difficult to observe from ground-based telescopes due to telluric water and other technical considerations related to telescopes and spectrometers."
"The depth and shape of the 3 µm absorption band in carbonaceous chondrites are influenced by many factors such as mineral assemblage, chemical compositions of component minerals, water content, and the grain sizes of minerals. Differences of the surface albedo and other factors, space weathering [Sasaki et al., 2001] for example, may also affect the depth and shape of the absorption in asteroids’ spectra. It was also demonstrated that the degree of thermal metamorphism (or the maximum heating temperature) of carbonaceous chondrites influences the 3 µm absorption feature [e.g., Hiroi et al., 1996]."
"Water ice is one of the possible candidates that can explain the flat 3.0–3.5 µm spectral feature of 773 Irmintraud because of its similarity to the spectrum of asteroid 1 Ceres [Lebofsky et al., 1981]. The 3.1 µm feature of 1 Ceres imposes the presence of possible water ice such as frost on the asteroid [Lebofsky et al., 1981]."
"Although 773 Irmintraud, which is 99 km in diameter [Gradie and Tedesco, 1982] at 2.857 AU in semimajor axis is under the condition that water ice is not retained on the surface, it might be possible that the ice is surviving for a long time just under the covered surface materials where sublimation temperature is high with the depth."
The "efforts to study the 21 cm hydrogen line from the northern and southern hemispheres in 1954 and 1959 [...] were combined and provided the first full-galaxy radio map of neutral hydrogen in the Milky Way".
"Instrumental neutron activation analyses of Kilauean aerosols collected in 1984 show Ir:Au:Re ratios of 1:12:2000 normalized to CI chondrites. The large Re enrichment in these volcanic aerosols may explain the 3 to 15-fold Re excess, relative to chondritic, in the observed siderophile element signature of the Cretaceous-Tertiary boundary clay layer.2,3 Strong evidence exists that an impact of an extraterrestrial body on the Earth caused mass extinctions at the end of the Cretaceous period.4,5 ... A Kilauean aerosol contribution of only 0.01 % of the chondritic component in the boundary clay layer would produce the observed Re enrichments."
"The Kilauea volcano on Hawaii represents hot spot volcanism in oceanic crust. Eruptive activity increased in 1983, resulting in the discovery of siderophile element enrichments in Kilauean aerosols, including an Ir:Al ratio 17,000 times its value in Hawaiian basalts.1"
"HC5N is the second molecule, after HC3N, in terms of total number of lines detected in the millimeter spectrum of CRL 618. It is a linear molecule with a rotational constant of 1331.330 MHz and a dipole moment of 4.33 Debyes, first discovered in space by Little et al. (1978)."
"On the other hand, HC7N was first discovered in space by Kroto et al. (1978)."
The "gas shells surrounding the protoplanetary nebula CRL618, [have] the pure rotational lines of HC5N in its fundamental and the lowest 4 vibrationally excited states (first astronomical source in which vibrationally excited HC5N has been detected), and HC7N rotational lines in its fundamental vibrational state."
"The Tagish Lake meteorite was identified as the first possible meteorite that came from a D type asteroid [Hiroi et al., 2001]. The Tagish Lake meteorite is a very carbon rich (4–5 wt.%), aqueously altered carbonaceous chondrite, containing an exceptionally high concentration of presolar grains and Ca-Fe-Mg carbonates, but an unusually low amount of high-temperature nebular materials such as chondrules and calcium-aluminum rich inclusions (CAI) [Brown et al., 2000]."
"The Martian (SNC) meteorites are critically important for understanding Mars because they provide details of petrography and chemistry that cannot (yet) be measured in situ, and they provide ‘‘ground truths’’ for spectral analyses from the Martian surface using Mo¨ssbauer, thermal emission, and visible, near-IR, and mid-IR reflectance techniques. The recent discovery of a new 815 g Martian meteorite in the Miller Range of Antarctica [Satterwhite and Righter, 2004] provides us with a new sample with which to test hypotheses developed in studies of other nakhlite samples."
The first recorded occurrence of smectite in an ordinary chondrite have been documented.
"[James Stanley Hey is] credited with discovering radio emissions from the Sun in early 1942. As with many important discoveries, his was accidental. He had been trying to resolve interference problems in England's defense radar systems during World War II and on one particular day noticed "the directions of maximum interference recorded by the operators appeared to follow the Sun." He checked with the Royal Observatory in Greenwich and was told an exceptionally active sunspot was moving across the solar disk, and on the day in question it was on a north-south line passing through the center of the Sun's disk as viewed from the Earth (the central meridian). He wrote a report on his findings but met skepticism from several radio scientists, partly because he was a comparative novice at the time. However, later in 1942, another radar scientist, G.C. Southworth in the USA, used the Sun in testing radar receivers, thus confirming the emissions."
"Magnetite was detected in the first two rocks ground by Spirit."
"Magnesian clay or clay-type minerals have been conclusively detected in the martian regolith."
"Near-IR (0.65-2.55 µm) spectral observations of Mars using the Mauna Kea 2.2-m telescope in April 1980 show weak but definite absorption bands near 2.35 µm. ... The absorption band positions and widths match those produced by combined OH stretch and Mg-OH lattice modes and are diagnostic of minerals with structural OH such as clays and amphiboles. Likely candidate minerals include serpentine, talc, hectorite, and saponite."
"In 2000, 433 Eros became the first asteroid to be orbited by a spacecraft, NEAR Shoemaker (Yeomans et al., 2000)."
"More than 150 years after the discovery of 4 Vesta in 1807, Hertz (1966) made the first asteroid mass determination by analyzing its perturbation on 197 Arete."
"The masses of 253 Mathide (Yeomans et al., 1998) and Eros (Yeomans et al., 2000) are the first two asteroid masses determined by observing the perturbation of a spacecraft in the vicinity of the asteroid."
Over the history of radiation astronomy a number of sources have been found. These are located on the celestial sphere using coordinate systems, including behind, in, on, or above the Earth.
- Looking for a first astronomical source that may be further back in time than the currently accepted oldest source is original research.
- First astronomical X-ray source
- First blue source in Boötes
- First cyan source in Caelum
- First gamma-ray source in Triangulum Australe
- First orange source in Cancer
- First red source in Canis Major
- First X-ray source in Andromeda
- First X-ray source in Antlia
- First X-ray source in Apus
- First X-ray source in Aquarius
- First yellow source in Aquila
- Serpens X-1
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