First life in primordial-planet oceans: the
... settling on free-fall timescales ~(ρG)-1/2 less than a million years. Melted by friction and gravitational potential energy of mergers, iron-nickel and molten rocky cores will be the first to form, surrounded by hot organic soup oceans under very high pressures arising from overlying massive H-He at ...
... settling on free-fall timescales ~(ρG)-1/2 less than a million years. Melted by friction and gravitational potential energy of mergers, iron-nickel and molten rocky cores will be the first to form, surrounded by hot organic soup oceans under very high pressures arising from overlying massive H-He at ...
1. INTRODUCTION
... We report results of a search for planets around 530 main-sequence stars using the Keck HIRES spectrometer, which has provided Doppler precision of 3 m s~1 during the past 3 yr. We report six new strong planet candidates having complete Keplerian orbits, with periods ranging from 24 days to 3 yr. Th ...
... We report results of a search for planets around 530 main-sequence stars using the Keck HIRES spectrometer, which has provided Doppler precision of 3 m s~1 during the past 3 yr. We report six new strong planet candidates having complete Keplerian orbits, with periods ranging from 24 days to 3 yr. Th ...
Reconstructing the evolution of double helium white dwarfs
... We use a parametric approach to describe mass transfer in low-mass binaries, where both stars are of comparable mass and find that the orbital characteristics of the observed double helium white dwarfs can be well reproduced if the envelope of the primary is lost with ∼1.5 times the specific angular m ...
... We use a parametric approach to describe mass transfer in low-mass binaries, where both stars are of comparable mass and find that the orbital characteristics of the observed double helium white dwarfs can be well reproduced if the envelope of the primary is lost with ∼1.5 times the specific angular m ...
Camelopardalis-Better-Know-A-Constellation
... • Although Camelopardalis is the 18th largest constellation, (757 sq. deg. ) it is not a particularly bright constellation, as the brightest stars are only of fourth magnitude. • β Camelopardalis is the brightest star, at apparent magnitude 4.03. This star is a double star, with components of magnit ...
... • Although Camelopardalis is the 18th largest constellation, (757 sq. deg. ) it is not a particularly bright constellation, as the brightest stars are only of fourth magnitude. • β Camelopardalis is the brightest star, at apparent magnitude 4.03. This star is a double star, with components of magnit ...
A Compact Central Object in the Supernova Remnant Kes 79
... the remnant of the core of the star which exploded to produce Kes 79. It was not detected in previous X-ray observations because the counting rate of the central source is only ∼ 10−2 that of the entire remnant in the 1-10 keV energy band. The luminosity at 10 kpc distance, in the band 0.3-8 keV, is ...
... the remnant of the core of the star which exploded to produce Kes 79. It was not detected in previous X-ray observations because the counting rate of the central source is only ∼ 10−2 that of the entire remnant in the 1-10 keV energy band. The luminosity at 10 kpc distance, in the band 0.3-8 keV, is ...
X-ray emission from young pulsar, PWN and SNRs
... • Most of the filaments contain point-like sources at their heads. • All the filaments cometaryare morphology. The X-ray show filaments most • The spectra are non-thermal, with photon indices probably close to Sgr A* and ...
... • Most of the filaments contain point-like sources at their heads. • All the filaments cometaryare morphology. The X-ray show filaments most • The spectra are non-thermal, with photon indices probably close to Sgr A* and ...
MOLECULAR OUTFLOWS AND A MID
... PAH emission features stimulated by UV radiation from the cluster. The subject of this paper is the dark filament in the top left which is forming early B stars. The mid-IR emission from the UC H ii region G34.4+0.23 is significantly less than that of G34.26, as expected due to the lower luminosity ...
... PAH emission features stimulated by UV radiation from the cluster. The subject of this paper is the dark filament in the top left which is forming early B stars. The mid-IR emission from the UC H ii region G34.4+0.23 is significantly less than that of G34.26, as expected due to the lower luminosity ...
File
... Not all electromagnetic radiation coming from space reaches the Earth's surface. The diagram shows how far radiation from each part of the electromagnetic spectrum travels down through the atmosphere. ...
... Not all electromagnetic radiation coming from space reaches the Earth's surface. The diagram shows how far radiation from each part of the electromagnetic spectrum travels down through the atmosphere. ...
Classical Oe Stars in the Field of the Small Magellanic Cloud
... shape the evolution of their host galaxies through strong stellar winds and radiative feedback, which shock heat and ionize the surrounding gas, injecting energy into the interstellar medium (ISM). Moreover, when massive stars end their lives as core-collapse supernovae, the shockwaves can trigger o ...
... shape the evolution of their host galaxies through strong stellar winds and radiative feedback, which shock heat and ionize the surrounding gas, injecting energy into the interstellar medium (ISM). Moreover, when massive stars end their lives as core-collapse supernovae, the shockwaves can trigger o ...
Gaia - STScI
... Bright stars will give rigid tie between LSST and Gaia. Faint stars (down to 26th and beyond) will deliver the new science. Gaia has 2 fields of regard in same focal plane. At some star density, confusion will degrade accuracy. LSST has bigger images but a single field of regard. LSST can do differe ...
... Bright stars will give rigid tie between LSST and Gaia. Faint stars (down to 26th and beyond) will deliver the new science. Gaia has 2 fields of regard in same focal plane. At some star density, confusion will degrade accuracy. LSST has bigger images but a single field of regard. LSST can do differe ...
Planetary system formation in thermally evolving viscous
... two-dimensional simulations were performed for 5 M⊕ planets embedded in discs with scale height h = 0.03, 0.05, 0.07 and 0.1. Additional simulations for 10 M⊕ planets embedded in a disc with h = 0.1 were also performed. Eccentricities in the range 0 ≤ e ≤ 0.3 were considered. Figure 1a shows the tim ...
... two-dimensional simulations were performed for 5 M⊕ planets embedded in discs with scale height h = 0.03, 0.05, 0.07 and 0.1. Additional simulations for 10 M⊕ planets embedded in a disc with h = 0.1 were also performed. Eccentricities in the range 0 ≤ e ≤ 0.3 were considered. Figure 1a shows the tim ...
Classification of Variable Stars
... V1668 Cyg. These are stars in constellations for which all of the letter combinations have been exhausted. (i.e. V746 Oph is the 746th variable to be discovered in Ophiuchus.) Variable star names are determined by a committee appointed by the International Astronomical Union (I.A.U.). The assignment ...
... V1668 Cyg. These are stars in constellations for which all of the letter combinations have been exhausted. (i.e. V746 Oph is the 746th variable to be discovered in Ophiuchus.) Variable star names are determined by a committee appointed by the International Astronomical Union (I.A.U.). The assignment ...
uv surface environment of earth-like planets orbiting
... We focus on four geological epochs from Earth’s history to model the UV environment on the surface of an Earth-like planet at the 1 AU equivalent distance from its host star. The geological evidence from 2.8–3.5 Ga is consistent with an atmosphere with similar atmospheric pressure as modern Earth (S ...
... We focus on four geological epochs from Earth’s history to model the UV environment on the surface of an Earth-like planet at the 1 AU equivalent distance from its host star. The geological evidence from 2.8–3.5 Ga is consistent with an atmosphere with similar atmospheric pressure as modern Earth (S ...
A Digital Spectral Classification Atlas
... autonomy of the system as well as ensuring that different observers will classify stars on the same system. When the MK system was first defined, it was based on photographic spectra in the blue-violet part of the spectrum. This was done by necessity, as scientific photographic emulsions in the 1940 ...
... autonomy of the system as well as ensuring that different observers will classify stars on the same system. When the MK system was first defined, it was based on photographic spectra in the blue-violet part of the spectrum. This was done by necessity, as scientific photographic emulsions in the 1940 ...
THE ABSOLUTE MAGNITUDE OF RR LYRAE - Cosmos
... distance scale to the globular clusters by subdwarf main-sequence tting, using Hipparcos parallax data, leading to MV =0.15 at [Fe/H]={2.1. These bright values of MV give much younger age for the oldest globular clusters than the previous estimation (Bolte & Hogan 1995, Chaboyer et al. 1996b). Howe ...
... distance scale to the globular clusters by subdwarf main-sequence tting, using Hipparcos parallax data, leading to MV =0.15 at [Fe/H]={2.1. These bright values of MV give much younger age for the oldest globular clusters than the previous estimation (Bolte & Hogan 1995, Chaboyer et al. 1996b). Howe ...
The rebirth of Supernova 1987A a study of the ejecta-ring collision
... ejecta with the inner circumstellar ring, SN 1987A is dramatically evolving at all wavelengths on time scales less than a year. This makes SN 1987A a great “laboratory” for studies of shock physics. Repeated observations of the ejecta-ring collision have been carried out using the UVES echelle spect ...
... ejecta with the inner circumstellar ring, SN 1987A is dramatically evolving at all wavelengths on time scales less than a year. This makes SN 1987A a great “laboratory” for studies of shock physics. Repeated observations of the ejecta-ring collision have been carried out using the UVES echelle spect ...
Nuclear astrophysics: the unfinished quest for the origin of the
... Most of the ordinary (visible) matter in the Universe, from a tiny terrestrial pebble to a giant star, is composed of protons and neutrons (nucleons). These nucleons can assemble in a suite of different nuclear configurations. The masses of such bound nuclei are actually smaller than the sum of the ...
... Most of the ordinary (visible) matter in the Universe, from a tiny terrestrial pebble to a giant star, is composed of protons and neutrons (nucleons). These nucleons can assemble in a suite of different nuclear configurations. The masses of such bound nuclei are actually smaller than the sum of the ...
The Kuiper Belt and Other Debris Disks - UCLA
... Comets are icy bodies which sublimate in the heat of the Sun, producing observationally diagnostic unbound atmospheres or “comae”. For most known comets, the sublimation is sufficiently strong that mass loss cannot be sustained for much longer than ∼104 yr, a tiny fraction of the age of the Solar sy ...
... Comets are icy bodies which sublimate in the heat of the Sun, producing observationally diagnostic unbound atmospheres or “comae”. For most known comets, the sublimation is sufficiently strong that mass loss cannot be sustained for much longer than ∼104 yr, a tiny fraction of the age of the Solar sy ...
Star formation
Star formation is the process by which dense regions within molecular clouds in interstellar space, sometimes referred to as ""stellar nurseries"" or ""star-forming regions"", collapse to form stars. As a branch of astronomy, star formation includes the study of the interstellar medium (ISM) and giant molecular clouds (GMC) as precursors to the star formation process, and the study of protostars and young stellar objects as its immediate products. It is closely related to planet formation, another branch of astronomy. Star formation theory, as well as accounting for the formation of a single star, must also account for the statistics of binary stars and the initial mass function.In June 2015, astronomers reported evidence for Population III stars in the Cosmos Redshift 7 galaxy at z = 6.60. Such stars are likely to have existed in the very early universe (i.e., at high redshift), and may have started the production of chemical elements heavier than hydrogen that are needed for the later formation of planets and life as we know it.