Debris disks from an astronomical and an astrobiological viewpoint Gianni Cataldi
... where a is the semi-major axis (in AU) of the parent body producing the dust, and M∗ the mass of the host star (in units of M⊕ ). Note that tbl is nothing but the orbital period of the parent planetesimal. For the β Pic system tbl ≈ 750 yr, whereas the age is estimated to be 10–20 Myr (Mentuch et al ...
... where a is the semi-major axis (in AU) of the parent body producing the dust, and M∗ the mass of the host star (in units of M⊕ ). Note that tbl is nothing but the orbital period of the parent planetesimal. For the β Pic system tbl ≈ 750 yr, whereas the age is estimated to be 10–20 Myr (Mentuch et al ...
THE NEW GALAXY: Signatures of Its Formation
... billion stars, within a sphere of diameter 20 kpc (the Gaiasphere). In “The Gaiasphere and The Limits of Knowledge” below, we look forward to a time when all stars within the Gaiasphere have complete chemical abundance measurements (including all heavy metals). Even with such a vast increase in info ...
... billion stars, within a sphere of diameter 20 kpc (the Gaiasphere). In “The Gaiasphere and The Limits of Knowledge” below, we look forward to a time when all stars within the Gaiasphere have complete chemical abundance measurements (including all heavy metals). Even with such a vast increase in info ...
Multiwavelength Observations of Massive Stellar Cluster Candidates
... center were uncovered with infrared spectroscopic observations, and are responsible for heating and shaping much of the surrounding ISM (Cotera et al. 1996; Figer et al. 1999ab; Lang et al. 1997, 2001a, 2002). In addition, several other young, massive clusters in the Galaxy have been recently studie ...
... center were uncovered with infrared spectroscopic observations, and are responsible for heating and shaping much of the surrounding ISM (Cotera et al. 1996; Figer et al. 1999ab; Lang et al. 1997, 2001a, 2002). In addition, several other young, massive clusters in the Galaxy have been recently studie ...
MAXI J1659-152 - UvA-DARE
... GRB 100925A and which had brightened since 2010 September 25 02:30 UTC (Negoro et al. 2010). The discovery initiated several multi-wavelength observations (ground and space-based; e.g., van der Horst et al. 2010; Kuulkers et al. 2010b,c; see also Kuulkers et al. 2012a). The Galactic origin of MAXI J ...
... GRB 100925A and which had brightened since 2010 September 25 02:30 UTC (Negoro et al. 2010). The discovery initiated several multi-wavelength observations (ground and space-based; e.g., van der Horst et al. 2010; Kuulkers et al. 2010b,c; see also Kuulkers et al. 2012a). The Galactic origin of MAXI J ...
A FUSE Survey of Coronal Forbidden Lines in Late
... Because of our relatively poor knowledge of the rest wavelengths of these lines, the relatively weak signal of the coronal lines, and the moderate likelihood of coincidental blends with low-temperature lines, labeling spectral features located at wavelengths coincident with an expected coronal line ...
... Because of our relatively poor knowledge of the rest wavelengths of these lines, the relatively weak signal of the coronal lines, and the moderate likelihood of coincidental blends with low-temperature lines, labeling spectral features located at wavelengths coincident with an expected coronal line ...
Planet or brown dwarf? Inferring the companion mass in HD 100546
... existed, with an estimated companion mass of ∼10 MJup . The gap was later confirmed using mid-infrared nulling interferometry (Liu et al. 2003), UV spectroscopy (Grady et al. 2005), nearinfrared CO spectroscopy (Brittain et al. 2009; Van Der Plas et al. 2009), and mid-infrared interferometry (Panić ...
... existed, with an estimated companion mass of ∼10 MJup . The gap was later confirmed using mid-infrared nulling interferometry (Liu et al. 2003), UV spectroscopy (Grady et al. 2005), nearinfrared CO spectroscopy (Brittain et al. 2009; Van Der Plas et al. 2009), and mid-infrared interferometry (Panić ...
The 0.5-2.22µm Scattered Light Spectrum of the Disk Around TW
... 2006). The TW Hya stars may not be coeval, and TW Hya could even be at the young end of their age distribution (Weinberger et al. 2013). Associations just a bit older than TW Hya, such as β Pic, have no optically thick, massive protoplanetary disks. Despite reservations about its representativeness, ...
... 2006). The TW Hya stars may not be coeval, and TW Hya could even be at the young end of their age distribution (Weinberger et al. 2013). Associations just a bit older than TW Hya, such as β Pic, have no optically thick, massive protoplanetary disks. Despite reservations about its representativeness, ...
Volatiles in protoplanetary disks
... Volatiles are compounds with low sublimation temperatures, and they make up most of the condensible mass in typical planet-forming environments. They consist of relatively small, often hydrogenated, molecules based on the abundant elements carbon, nitrogen and oxygen. Volatiles are central to the pr ...
... Volatiles are compounds with low sublimation temperatures, and they make up most of the condensible mass in typical planet-forming environments. They consist of relatively small, often hydrogenated, molecules based on the abundant elements carbon, nitrogen and oxygen. Volatiles are central to the pr ...
Volatiles in protoplanetary disks
... Volatiles are compounds with low sublimation temperatures, and they make up most of the condensible mass in typical planet-forming environments. They consist of relatively small, often hydrogenated, molecules based on the abundant elements carbon, nitrogen and oxygen. Volatiles are central to the pr ...
... Volatiles are compounds with low sublimation temperatures, and they make up most of the condensible mass in typical planet-forming environments. They consist of relatively small, often hydrogenated, molecules based on the abundant elements carbon, nitrogen and oxygen. Volatiles are central to the pr ...
Compact High-Redshift Galaxies Are the Cores of the Most Massive
... from photometry and spectroscopy in Kriek et al. (2006, 2008b,a). We plot the profile of each system over the maximum radial range observed: from the scale of a single pixel at the observed redshift to the limiting surface brightness depth of the best images. Both the low and high-redshift systems a ...
... from photometry and spectroscopy in Kriek et al. (2006, 2008b,a). We plot the profile of each system over the maximum radial range observed: from the scale of a single pixel at the observed redshift to the limiting surface brightness depth of the best images. Both the low and high-redshift systems a ...
Michell, Laplace and the Origin of the Black Hole Concept
... Herschel’s two 1782 papers, and especially the catalogue of double stars, provided Michell with the ‘means’ on which to base his second astronomical paper, which bears the exceedingly long and laborious title, “On the Means of Discovering the Distance, Magnitude, &c. of the Fixed Stars, in Consequen ...
... Herschel’s two 1782 papers, and especially the catalogue of double stars, provided Michell with the ‘means’ on which to base his second astronomical paper, which bears the exceedingly long and laborious title, “On the Means of Discovering the Distance, Magnitude, &c. of the Fixed Stars, in Consequen ...
Hint of a transiting extended atmosphere on 55 Cancri b⋆
... to its star and a farther out giant planet (55 Cnc b), found in milder irradiation conditions with respect to other known hot Jupiters. This system raises important questions on the evolution of atmospheres for close-in exoplanets, and the dependence with planetary mass and irradiation. These questi ...
... to its star and a farther out giant planet (55 Cnc b), found in milder irradiation conditions with respect to other known hot Jupiters. This system raises important questions on the evolution of atmospheres for close-in exoplanets, and the dependence with planetary mass and irradiation. These questi ...
Title The molecular envelope around the red supergiant VY CMa
... The morphology and kinematics of the 12CO(2–1) emission around VY CMa do not reproduce those of a typical spherical expanding shell. We interpret the east and west offset bright peaks, with high velocity relative to the systemic velocity, as the signature of a east-west bipolar outflow. Shinnaga et ...
... The morphology and kinematics of the 12CO(2–1) emission around VY CMa do not reproduce those of a typical spherical expanding shell. We interpret the east and west offset bright peaks, with high velocity relative to the systemic velocity, as the signature of a east-west bipolar outflow. Shinnaga et ...
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... The ages of individual Vega-type stars span their whole main-sequence lifetime. We are thus not merely witnessing the “excesses of the youth,” phenomena found only in Young Stellar Objects and the pre-main sequence stars, lasting for a few million years (denoted Myr hereafter). While there is a grow ...
... The ages of individual Vega-type stars span their whole main-sequence lifetime. We are thus not merely witnessing the “excesses of the youth,” phenomena found only in Young Stellar Objects and the pre-main sequence stars, lasting for a few million years (denoted Myr hereafter). While there is a grow ...
PowerPoint file - Departament d`Astronomia i Meteorologia
... Weak continuum emission at 230 GHz (at a 6 level) is found associated with IRS 1 with a flux density of 18.3 mJy. For a dust temperature between 20 K (from NH3 Miralles et al. 1994) and 44 K (derived from the SED, Sridharan et al. 2002), the mass of gas and dust toward IRS 1 results in 0.3-0.6 M. ...
... Weak continuum emission at 230 GHz (at a 6 level) is found associated with IRS 1 with a flux density of 18.3 mJy. For a dust temperature between 20 K (from NH3 Miralles et al. 1994) and 44 K (derived from the SED, Sridharan et al. 2002), the mass of gas and dust toward IRS 1 results in 0.3-0.6 M. ...
3 science case - Giant Magellan Telescope Organization
... Astronomy is a science driven by discovery. Bereft of physical contact with the celestial objects we study, astronomers can rarely carry out the controlled experiments that are the hallmark of the scientific method. Progress in our understanding of the cosmos often proceeds from the discovery of new ...
... Astronomy is a science driven by discovery. Bereft of physical contact with the celestial objects we study, astronomers can rarely carry out the controlled experiments that are the hallmark of the scientific method. Progress in our understanding of the cosmos often proceeds from the discovery of new ...
The Massive Star Population of Cygnus OB2
... The Massive Star Population of Cygnus OB2 Wright et al. (2010b) found the lower-mass IMF to be in agreement with the Salpeter value. Work over the past decade has assembled the data needed to form a much fuller view of the OB population in Cyg OB2, thanks to a combination of new spectroscopic surve ...
... The Massive Star Population of Cygnus OB2 Wright et al. (2010b) found the lower-mass IMF to be in agreement with the Salpeter value. Work over the past decade has assembled the data needed to form a much fuller view of the OB population in Cyg OB2, thanks to a combination of new spectroscopic surve ...
The X-ray emission from shock cooling zones in O star winds
... Hillier et al. achieved a reasonable fit to the observations with the assumption that all shocks were characterized by a single temperature of log T [K] ≈ 6.60 (see their Fig. 2). But the flux deficiency in the calculated spectrum for energies below 0.45 keV indicated that a cooler shock component o ...
... Hillier et al. achieved a reasonable fit to the observations with the assumption that all shocks were characterized by a single temperature of log T [K] ≈ 6.60 (see their Fig. 2). But the flux deficiency in the calculated spectrum for energies below 0.45 keV indicated that a cooler shock component o ...
Cygnus X-1
Cygnus X-1 (abbreviated Cyg X-1) is a well-known galactic X-ray source, thought to be a black hole, in the constellation Cygnus. It was discovered in 1964 during a rocket flight and is one of the strongest X-ray sources seen from Earth, producing a peak X-ray flux density of 6977229999999999999♠2.3×10−23 Wm−2 Hz−1 (7003230000000000000♠2.3×103 Jansky). Cygnus X-1 was the first X-ray source widely accepted to be a black hole and it remains among the most studied astronomical objects in its class. The compact object is now estimated to have a mass about 14.8 times the mass of the Sun and has been shown to be too small to be any known kind of normal star, or other likely object besides a black hole. If so, the radius of its event horizon is about 7004440000000000000♠44 km.Cygnus X-1 belongs to a high-mass X-ray binary system about 7019574266339685654♠6070 ly from the Sun that includes a blue supergiant variable star designated HDE 226868 which it orbits at about 0.2 AU, or 20% of the distance from the Earth to the Sun. A stellar wind from the star provides material for an accretion disk around the X-ray source. Matter in the inner disk is heated to millions of degrees, generating the observed X-rays. A pair of jets, arranged perpendicular to the disk, are carrying part of the energy of the infalling material away into interstellar space.This system may belong to a stellar association called Cygnus OB3, which would mean that Cygnus X-1 is about five million years old and formed from a progenitor star that had more than 7001400000000000000♠40 solar masses. The majority of the star's mass was shed, most likely as a stellar wind. If this star had then exploded as a supernova, the resulting force would most likely have ejected the remnant from the system. Hence the star may have instead collapsed directly into a black hole.Cygnus X-1 was the subject of a friendly scientific wager between physicists Stephen Hawking and Kip Thorne in 1975, with Hawking betting that it was not a black hole. He conceded the bet in 1990 after observational data had strengthened the case that there was indeed a black hole in the system. This hypothesis has not been confirmed due to a lack of direct observation but has generally been accepted from indirect evidence.