18 research outputs found
The Architectural Design Rules of Solar Systems based on the New Perspective
On the basis of the Lunar Laser Ranging Data released by NASA on the Silver
Jubilee Celebration of Man Landing on Moon on 21st July 1969-1994, theoretical
formulation of Earth-Moon tidal interaction was carried out and Planetary
Satellite Dynamics was established. It was found that this mathematical
analysis could as well be applied to Star and Planets system and since every
star could potentially contain an extra-solar system, hence we have a large
ensemble of exoplanets to test our new perspective on the birth and evolution
of solar systems. Till date 403 exoplanets have been discovered in 390
extra-solar systems. I have taken 12 single planet systems, 4 Brown Dwarf -
Star systems and 2 Brown Dwarf pairs. Following architectural design rules are
corroborated through this study of exoplanets. All planets are born at inner
Clarke Orbit what we refer to as inner geo-synchronous orbit in case of
Earth-Moon System. By any perturbative force such as cosmic particles or
radiation pressure, the planet gets tipped long of aG1 or short of aG1. Here
aG1 is inner Clarke Orbit. The exoplanet can either be launched on death spiral
as CLOSE HOT JUPITERS or can be launched on an expanding spiral path as the
planets in our Solar System are. It was also found that if the exo-planet are
significant fraction of the host star then those exo-planets rapidly migrate
from aG1 to aG2 and have very short Time Constant of Evolution as Brown Dwarfs
have. This vindicates our basic premise that planets are always born at inner
Clarke Orbit. This study vindicates the design rules which had been postulated
at 35th COSPAR Scientific Assembly in 2004 at Paris, France, under the title
,New Perspective on the Birth & Evolution of Solar Systems.Comment: This paper has been reported to Earth,Moon and Planets Journal as
MOON-S-09-0007
Opening a new window to other worlds with spectropolarimetry
A high level of diversity has already been observed among the planets of our
own Solar System. As such, one expects extrasolar planets to present a wide
range of distinctive features, therefore the characterisation of Earth- and
super Earth-like planets is becoming of key importance in scientific research.
The SEARCH (Spectropolarimetric Exoplanet AtmospheRe CHaracerisation) mission
proposal of this paper represents one possible approach to realising these
objectives. The mission goals of SEARCH include the detailed characterisation
of a wide variety of exoplanets, ranging from terrestrial planets to gas
giants. More specifically, SEARCH will determine atmospheric properties such as
cloud coverage, surface pressure and atmospheric composition, and may also be
capable of identifying basic surface features. To resolve a planet with a semi
major axis of down to 1.4AU and 30pc distant SEARCH will have a mirror system
consisting of two segments, with elliptical rim, cut out of a parabolic mirror.
This will yield an effective diameter of 9 meters along one axis. A phase mask
coronagraph along with an integral spectrograph will be used to overcome the
contrast ratio of star to planet light. Such a mission would provide invaluable
data on the diversity present in extrasolar planetary systems and much more
could be learned from the similarities and differences compared to our own
Solar System. This would allow our theories of planetary formation, atmospheric
accretion and evolution to be tested, and our understanding of regions such as
the outer limit of the Habitable Zone to be further improved.Comment: 23 pages, accepted for publication in Experimental Astronom
Type Ia Supernovae and the Hubble Constant
The focus of this review is the work that has been done during the 1990s on
using Type Ia supernovae (SNe Ia) to measure the Hubble constant (). SNe
Ia are well suited for measuring . A straightforward maximum-light color
criterion can weed out the minority of observed events that are either
intrinsically subluminous or substantially extinguished by dust, leaving a
majority subsample that has observational absolute-magnitude dispersions of
less than mag.
Correlations between absolute magnitude and one or more distance-independent SN
Ia or parent-galaxy observables can be used to further standardize the absolute
magnitudes to better than 0.2 mag. The absolute magnitudes can be calibrated in
two independent ways --- empirically, using Cepheid-based distances to parent
galaxies of SNe Ia, and physically, by light curve and spectrum fitting. At
present the empirical and physical calibrations are in agreement at or -19.5. Various ways that have been used to match
Cepheid-calibrated SNe Ia or physical models to SNe Ia that have been observed
out in the Hubble flow have given values of distributed throughout the
range 54 to 67 km/s Mpc. Astronomers who want a consensus value of
from SNe Ia with conservative errors could, for now, use km/s
Mpc^{-1}$.Comment: 46 pages. Hard copies of figures, all from the published literature,
can be obtained from the author. With permission, from the Annual Review of
Astronomy and Astrophysics, Volume 36, copyright 1998, by Annual Review
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HAT-P-32b and HAT-P-33b: Two Highly Inflated Hot Jupiters Transiting High-jitter Stars
We report the discovery of two exoplanets transiting high-jitter stars. HAT-P-32b orbits the bright V = 11.289 late-Fâearly-G dwarf star GSC 3281-00800, with a period P = 2 . 150008 ± 0 . 000001 d. The stellar and planetary masses and radii depend on the eccentricity of the system, which is poorly constrained due to the high-velocity jitter ( ⌠80 m s â 1 ). Assuming a circular orbit, the star has a mass of 1 . 16 ± 0 . 04 M and radius of 1 . 22 ± 0 . 02 R , while the planet has a mass of 0 . 860 ± 0 . 164 M J and a radius of 1 . 789 ± 0 . 025 R J . The second planet, HAT-P-33b, orbits the bright V = 11.188 late-F dwarf star GSC 2461-00988, with a period P = 3 . 474474 ± 0 . 000001 d. As for HAT-P-32, the stellar and planetary masses and radii of HAT-P-33 depend on the eccentricity, which is poorly constrained due to the high jitter ( ⌠50 m s â 1 ). In this case, spectral line bisector spans (BSs) are significantly anti-correlated with the radial velocity residuals, and we are able to use this correlation to reduce the residual rms to ⌠35 m s â 1 . We find that the star has a mass of 1 . 38 ± 0 . 04 M and a radius of 1 . 64 ± 0 . 03 R while the planet has a mass of 0 . 762 ± 0 . 101 M J and a radius of 1 . 686 ± 0 . 045 R J for an assumed circular orbit. Due to the large BS variations exhibited by both stars we rely on detailed modeling of the photometric light curves to rule out blend scenarios. Both planets are among the largest radii transiting planets discovered to date
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HAT-P-20b-HAT-P-23b: Four Massive Transiting Extrasolar Planets
We report the discovery of four relatively massive (2â7 M J ) transiting extrasolar planets. HAT-P-20b orbits the moderately bright V = 11.339 K3 dwarf star GSC 1910-00239 on a circular orbit, with a period P = 2 . 875317 ± 0 . 000004 days, transit epoch T c = 2455080 . 92661 ± 0 . 00021 (BJD UTC ), and transit dura- tion 0 . 0770 ± 0 . 0008 days. The host star has a mass of 0 . 76 ± 0 . 03 M , radius of 0 . 69 ± 0 . 02 R , effective temperature 4595 ± 80 K, and metallicity [Fe / H] = +0 . 35 ± 0 . 08. The planetary companion has a mass of 7 . 246 ± 0 . 187 M J and a radius of 0 . 867 ± 0 . 033 R J yielding a mean density of 13 . 78 ± 1 . 50 g cm â 3 . HAT-P-21b orbits the V = 11.685 G3 dwarf star GSC 3013-01229 on an eccentric ( e = 0 . 228 ± 0 . 016) orbit, with a period P = 4 . 124481 ± 0 . 000007 days, transit epoch T c = 2454996 . 41312 ± 0 . 00069, and transit duration 0 . 1530 ± 0 . 0027 days. The host star has a mass of 0 . 95 ± 0 . 04 M , radius of 1 . 10 ± 0 . 08 R , effective temperature 5588 ± 80 K, and metallicity [Fe / H] = +0 . 01 ± 0 . 08. The planetary companion has a mass of 4 . 063 ± 0 . 161 M J and a radius of 1 . 024 ± 0 . 092 R J yielding a mean density of 4 . 68 +1 . 59 â 0 . 99 gcm â 3 . HAT-P-21b is a borderline ob- ject between the pM and pL class planets, and the transits occur near apastron. HAT-P-22b orbits the bright V = 9.732 G5 dwarf star HD 233731 on a circular orbit, with a period P = 3 . 212220 ± 0 . 000009 days, transit epoch T c = 2454930 . 22001 ± 0 . 00025, and transit duration 0 . 1196 ± 0 . 0014 days. The host star has a mass of 0 . 92 ± 0 . 03 M , radius of 1 . 04 ± 0 . 04 R , effective temperature 5302 ± 80 K, and metallicity [Fe / H] = +0 . 24 ± 0 . 08. The planet has a mass of 2 . 147 ± 0 . 061 M J and a compact radius of 1 . 080 ± 0 . 058 R J yielding a mean density of 2 . 11 +0 . 40 â 0 . 29 gcm â 3 . The host star also harbors an M-dwarf companion at a wide separation. Finally, HAT-P-23b orbits the V = 12.432 G0 dwarf star GSC 1632-01396 on a close to circular orbit, with a period P = 1 . 212884 ± 0 . 000002 days, transit epoch T c = 2454852 . 26464 ± 0 . 00018, and transit duration 0 . 0908 ± 0 . 0007 days. The host star has a mass of 1 . 13 ± 0 . 04 M , radius of 1 . 20 ± 0 . 07 R , effective temperature 5905 ± 80 K, and metallicity [Fe / H] = +0 . 15 ± 0 . 04. The planetary companion has a mass of 2 . 090 ± 0 . 111 M J and a radius of 1 . 368 ± 0 . 090 R J yielding a mean density of 1 . 01 ± 0 . 18 g cm â 3 . HAT-P-23b is an inflated and massive hot Jupiter on a very short period orbit, and has one of the shortest characteristic infall times (7 . 5 +2 . 9 â 1 . 8 Myr) before it gets engulfed by the star