Space System Architecture of India's Aditya-L1 Mission to study the Sun

Abstract Chelyabinsk event of Feb 15, 2013 clearly demonstrated that decameter sizeNear EarthObjects (NEO) should be considered as hazardous ones. Another important lesson is that bodies approaching the Earth from day sky could not be discovered by any ground-based or near Earth space telescopes and the only way to detect these bodies reasonably well beforehand is to put the telescope(s) relatively far fromthe Earth.We proposed the project of space system SODA (System of Observation of Day-time Asteroids) for exhaustive detection of decameter (and larger) bodies approaching the Earth from the Sun direction (Chelyabinsk type meteoroids). The medium-size (30 cm) wide field telescopes are to be put into vicinity of L1 (Earth-Sun) point. Observations will be performed in barrier mode. Two options are considered: single spacecraft (SC) or pair of SCs. We describe major constituents and options of the project. The entire project could be implemented with off-shelf components and fits to low-cost project requirements. Special attention is paid to accuracy of orbit of the NEO. In a variant of two SCs capable to perform observation in triangulation mode accuracy of atmosphere entry point for Chelyabinsk-like body could be as high as few tens of kilometers.

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Chromospheric activity as a function of age in main-sequence stars

Symposium - International Astronomical Union ◽

10.1017/s0074180900053146 ◽

1966 ◽

Vol 24 ◽

pp. 40-43

Author(s):

O. C. Wilson ◽

A. Skumanich

Keyword(s):

Main Sequence ◽

The Sun ◽

Main Sequence Stars ◽

Tentative Conclusion ◽

Chromospheric Activity ◽

General Field ◽

Large Clusters

Evidence previously presented by one of the authors (1) suggests strongly that chromospheric activity decreases with age in main sequence stars. This tentative conclusion rests principally upon a comparison of the members of large clusters (Hyades, Praesepe, Pleiades) with non-cluster objects in the general field, including the Sun. It is at least conceivable, however, that cluster and non-cluster stars might differ in some fundamental fashion which could influence the degree of chromospheric activity, and that the observed differences in chromospheric activity would then be attributable to the circumstances of stellar origin rather than to age.

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Galactic orbits of stars

Symposium - International Astronomical Union ◽

10.1017/s0074180900105340 ◽

1966 ◽

Vol 25 ◽

pp. 93-97

Author(s):

Richard Woolley

Keyword(s):

Globular Cluster ◽

Potential Field ◽

High Velocity ◽

Velocity Vector ◽

Variable Stars ◽

The Sun ◽

Proper Motions ◽

Rr Lyrae ◽

The Galaxy

It is now possible to determine proper motions of high-velocity objects in such a way as to obtain with some accuracy the velocity vector relevant to the Sun. If a potential field of the Galaxy is assumed, one can compute an actual orbit. A determination of the velocity of the globular clusterωCentauri has recently been completed at Greenwich, and it is found that the orbit is strongly retrograde in the Galaxy. Similar calculations may be made, though with less certainty, in the case of RR Lyrae variable stars.

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Seti Space Missions

International Astronomical Union Colloquium ◽

10.1017/s0252921100015372 ◽

1997 ◽

Vol 161 ◽

pp. 761-776 ◽

Cited By ~ 1

Author(s):

Claudio Maccone

Keyword(s):

Electromagnetic Waves ◽

Space Missions ◽

Gravitational Lens ◽

The Sun ◽

Space Antenna ◽

Focal Distance ◽

Large Space ◽

The Earth ◽

Space Antennas ◽

New Space

AbstractSETI from space is currently envisaged in three ways: i) by large space antennas orbiting the Earth that could be used for both VLBI and SETI (VSOP and RadioAstron missions), ii) by a radiotelescope inside the Saha far side Moon crater and an Earth-link antenna on the Mare Smythii near side plain. Such SETIMOON mission would require no astronaut work since a Tether, deployed in Moon orbit until the two antennas landed softly, would also be the cable connecting them. Alternatively, a data relay satellite orbiting the Earth-Moon Lagrangian pointL2would avoid the Earthlink antenna, iii) by a large space antenna put at the foci of the Sun gravitational lens: 1) for electromagnetic waves, the minimal focal distance is 550 Astronomical Units (AU) or 14 times beyond Pluto. One could use the huge radio magnifications of sources aligned to the Sun and spacecraft; 2) for gravitational waves and neutrinos, the focus lies between 22.45 and 29.59 AU (Uranus and Neptune orbits), with a flight time of less than 30 years. Two new space missions, of SETI interest if ET’s use neutrinos for communications, are proposed.

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A Search for Dyson Spheres around Late-Type Stars in the Solar Neighborhood II

International Astronomical Union Colloquium ◽

10.1017/s0252921100015281 ◽

1997 ◽

Vol 161 ◽

pp. 707-709 ◽

Cited By ~ 1

Author(s):

Jun Jugaku ◽

Shiro Nishimura

Keyword(s):

Solar Neighborhood ◽

The Sun ◽

Late Type ◽

Solar Type

AbstractWe continued our search for partial (incomplete) Dyson spheres associated with 50 solar-type stars (spectral classes F, G, and K) within 25 pc of the Sun. No candidate objects were found.

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