scholarly journals Astroecology, cosmo-ecology, and the future of life

2014 ◽  
Vol 83 (4) ◽  
pp. 449-464
Author(s):  
Michael N. Mautner
Keyword(s):  
Agricultural Soils ◽  
Extraterrestrial Life ◽  
Solar Sails ◽  
Dwarf Stars ◽  
Nutrient Contents ◽  
Solar Systems ◽  
System A ◽  
The Galaxy ◽  
Red Dwarf Stars ◽  
The Universe

Astroecology concerns the relations between life and space resources, and cosmo-ecology extrapolates these relations to cosmological scales. Experimental astroecology can quantify the amounts of life that can be derived from space resources. For this purpose, soluble carbon and electrolyte nutrients were measured in asteroid/meteorite materials. Microorganisms and plant cultures were observed to grow on these materials, whose fertilities are similar to productive agricultural soils. Based on measured nutrient contents, the 10<sup>22</sup> kg carbonaceous asteroids can yield 10<sup>18</sup> kg biomass with N and P as limiting nutrients (compared with the estimated 10<sup>15</sup> kg biomass on Earth). These data quantify the amounts of life that can be derived from asteroids in terms of time-integrated biomass [<em>BIOTA</em><sub>int</sub> = biomass (kg) × lifetime (years)], as 10<sup>27</sup> kg-years during the next billion years of the Solar System (a thousand times the 10<sup>24</sup> kg-years to date). The 10<sup>26</sup> kg cometary materials can yield biota 10 000 times still larger. In the galaxy, potential future life can be estimated based on stellar luminosities. For example, the Sun will develop into a white dwarf star whose 10<sup>15</sup> W luminosity can sustain a <em>BIOTA</em><sub>int</sub> of 10<sup>34</sup> kg-years over 10<sup>20</sup> years. The 10<sup>12</sup> main sequence and white and red dwarf stars can sustain 10<sup>46</sup> kg-years of <em>BIOTA</em><sub>int</sub> in the galaxy and 10<sup>57</sup> kg-years in the universe. Life has great potentials in space, but the probability of present extraterrestrial life may be incomputable because of biological and ecological complexities. However, we can establish and expand life in space with present technology, by seeding new young solar systems. Microbial representatives of our life-form can be launched by solar sails to new planetary systems, including extremophiles suited to diverse new environments, autotrophs and heterotrophs to continually form and recycle biomolecules, and simple multicellulars to jump-start higher evolution. These programs can be motivated by life-centered biotic ethics that seek to secure and propagate life. In space, life can develop immense populations and diverse new branches. Some may develop into intelligent species that can expand life further in the galaxy, giving our human endeavors a cosmic purpose.

scholarly journals The Red Dwarf Star Population in the Galaxy

1995 ◽  
Vol 151 ◽  
pp. 55-56 ◽  
Author(s):  
L.V. Mirzoyan
Keyword(s):  
Star Clusters ◽  
Space Distribution ◽  
Dwarf Star ◽  
Star Clusters And Associations ◽  
Dwarf Stars ◽  
The Galaxy ◽  
Flare Stars ◽  
Red Dwarf Stars ◽  
T Tau ◽  
Stellar Associations

Red dwarf stars in the Galaxy occur in three forms: as flare stars, T Tau stars and red dwarf stars of constant brightness. Haro (1957) suggested that all these stars present regular evolutionary stages of red dwarf stars.The space distribution of UV Cet flare stars in the solar vicinity indicates that these low luminosity stars belong to the disk population of the Galaxy. Therefore one can suppose that all red dwarf stars have a space distribution which is similar to that of the flare stars (Mirzoyan et al. 1988a). Only a small part of them is found in star clusters and associations. The T Tau stars are an exception: because of their very short lifetime, all of them are found in stellar associations.The space distribution of red dwarf stars is determined by the fact that all of them are formed in star clusters and associations and are finally lost from their stellar systems and merge into the general galactic field (Mirzoyan 1995).

scholarly journals Distribution of red dwarfs in general galactic field on the basis of stellar star statistics

1990 ◽  
Vol 137 ◽  
pp. 59-62
Author(s):  
A.T. Garibjanian ◽  
V.V. Hambarian ◽  
L.V. Mirzoyan ◽  
A.L. Mirzoyan
Keyword(s):  
Uniform Distribution ◽  
Total Mass ◽  
Luminosity Function ◽  
Stellar Flare ◽  
Dwarf Stars ◽  
Galactic Field ◽  
Red Dwarfs ◽  
The Galaxy ◽  
Ceti Type ◽  
Red Dwarf Stars

The mathematical expectation for detection of stellar flare on UV Ceti type stars in the solar vicinity during photographic patrol observations with 40″ Shcmidt camera of the Byurakan Astrophysical Observatory is estimated. We use the luminosity function of the flaring red dwarfs the assume a uniform distribution in the general galactic field. Comparison with the results of photographic patrol supports this assumption. The numbers and total mass of the flare and non-flare red dwarf stars in the Galaxy for the uniform distribution are determined. They are not in contradiction with Oort's estimate of total mass of red dwarfs.

scholarly journals High-dispersion spectroscopy of extrasolar planets: from CO in hot Jupiters to O 2 in exo-Earths

2014 ◽  
Vol 372 (2014) ◽  
pp. 20130075 ◽  
Author(s):  
Ignas Snellen
Keyword(s):  
Carbon Monoxide ◽  
Image Quality ◽  
Extrasolar Planets ◽  
Low Cost ◽  
High Dispersion ◽  
Extraterrestrial Life ◽  
Dwarf Stars ◽  
Hot Jupiters ◽  
Red Dwarf Stars ◽  
Large Telescopes

Ground-based high-dispersion spectroscopy could reveal molecular oxygen as a biomarker gas in the atmospheres of twin-Earths transiting red dwarf stars within the next 25 years. The required contrasts are only a factor of 3 lower than that already achieved for carbon monoxide in hot Jupiter atmospheres today but will need much larger telescopes because the target stars will be orders of magnitude fainter. If extraterrestrial life is very common and can therefore be found on planets around the most nearby red dwarf stars, it may be detectable via transmission spectroscopy with the next-generation extremely large telescopes. However, it is likely that significantly more collecting area is required for this. This can be achieved through the development of low-cost flux collector technology, which combines a large collecting area with a low but sufficient image quality for high-dispersion spectroscopy of bright stars.

scholarly journals Wide-Field Photographic Versus Wide-Field CCD Techniques in the Activity Analysis of dM Stars

1994 ◽  
Vol 161 ◽  
pp. 61-64
Author(s):  
G. Szécsényi-Nagy
Keyword(s):  
Variable Stars ◽  
Activity Level ◽  
Wide Field ◽  
Dwarf Stars ◽  
Photoelectric Photometry ◽  
Stellar Flares ◽  
Red Dwarfs ◽  
The Galaxy ◽  
Flare Stars ◽  
Red Dwarf Stars

The Galaxy is abundant in red dwarf stars. According to statistical analyses, their majority is unstable. Simultaneously, more than 60% of the variable stars known in the solar vicinity (r &lt; 20 pc) are flare stars and taking into account the number of BY Dra stars too the proportion of red dwarfs amongst local variables is superior to three quarters. Their absolute visual magnitudes range from +6 to +17.5 or even more (Szécsényi-Nagy 1986a). During flare events their brightness may reach a maximum corresponding to an enhancement of 1000–10,000 times. The amplitude of a large flare in the U band may be as high as 8–10 magnitudes. The events take place nonperiodically in unpredictable moments; no unquestionable periodicity has been found in the time distribution of stellar flares. However the activity level of various flare stars is considerably different. Some of them show observable flare ups with a mean frequency of 1 per hour whilst others produce only one event per annum. For the scarcity of the phenomenon, traditional photoelectric photometry of individual stars is not an adequate means to a better understanding of flare stars.

scholarly journals Optical and H-Alpha Emission from Unresolved Red Dwarf Stars in the Galaxy

1990 ◽  
Vol 139 ◽  
pp. 107-109
Author(s):  
G. Szécsényi-Nagy
Keyword(s):  
Main Sequence ◽  
Stellar Content ◽  
Main Sequence Stars ◽  
M Dwarfs ◽  
Dwarf Stars ◽  
Alpha Emission ◽  
Cool Stars ◽  
Red Dwarfs ◽  
The Galaxy ◽  
Red Dwarf Stars

Although many of the nearest dim and cool stars (the red dwarfs) were catalogued in the early sixties, the majority of the astronomers did not realize that these objects provide almost nine tenths of all the stars in our Galaxy. In fact 90-95% of the stars in the solar vicinity (r ≤ 25 pc) are main sequence stars, and at least 80% of them are M dwarfs. Outside the main sequence (MS) one can find a few subdwarfs and somewhat more white dwarfs, but the contribution of this latter type is not known precisely. Estimates range between 4% and 8%. The relative frequency of giants and supergiants can not be determined from the census of the local star population because they are not represented in a statistically meaningful number. But investigations of much greater cosmic volumes demonstrate that luminosity classes Ia, Ib, II, III, and IV altogether contribute fewer than 1% of the stellar content of the Galaxy.

scholarly journals On the origin and evolution of life in the Galaxy

2010 ◽  
Vol 9 (4) ◽  
pp. 217-226 ◽  
Author(s):  
Michael McCabe ◽  
Holly Lucas
Keyword(s):  
Extraterrestrial Life ◽  
Evolutionary Transitions ◽  
Origin And Evolution ◽  
A Value ◽  
Evolution Of Life ◽  
Life On Mars ◽  
The Galaxy ◽  
The Origin Of Life ◽  
The Universe ◽  
Present Understanding

AbstractA simple stochastic model for evolution, based upon the need to pass a sequence of n critical steps is applied to both terrestrial and extraterrestrial origins of life. In the former case, the time at which humans have emerged during the habitable period of Earth suggests a value of n=4. Progressively adding earlier evolutionary transitions gives an optimum fit when n=5, implying either that their initial transitions are not critical or that habitability began around 6 Ga ago. The origin of life on Mars or elsewhere within the Solar System is excluded by the latter case and the simple anthropic argument is that extraterrestrial life is scarce in the Universe because it does not have time to evolve. Alternatively, the timescale can be extended if the migration of basic progenotic material to Earth is possible. If extra transitions are included in the model to allow for Earth migration, then the start of habitability needs to be even earlier than 6 Ga ago. Our present understanding of Galactic habitability and dynamics does not exclude this possibility. We conclude that Galactic punctuated equilibrium, proposed as a way round the anthropic problem, is not the only way of making life more common in the Galaxy.

Flaring red dwarf stars: news from Crimea

1998 ◽  
Vol 168 (8) ◽  
pp. 891 ◽  
Author(s):  
Roald E. Gershberg
Keyword(s):  
Dwarf Stars ◽  
Red Dwarf Stars

The Long View of Planetary Systems

2018 ◽  
Author(s):  
Karel Schrijver
Keyword(s):  
Solar System ◽  
Milky Way ◽  
Planetary Systems ◽  
Giant Planets ◽  
Milky Way Galaxy ◽  
Population Statistics ◽  
The Past ◽  
General Terms ◽  
The Galaxy ◽  
The Universe

How many planetary systems formed before our’s did, and how many will form after? How old is the average exoplanet in the Galaxy? When did the earliest planets start forming? How different are the ages of terrestrial and giant planets? And, ultimately, what will the fate be of our Solar System, of the Milky Way Galaxy, and of the Universe around us? We cannot know the fate of individual exoplanets with great certainty, but based on population statistics this chapter sketches the past, present, and future of exoworlds and of our Earth in general terms.

The Cosmic Mystery Tour

2019 ◽  
Author(s):  
Nicholas Mee
Keyword(s):  
Science Fiction ◽  
Particle Physics ◽  
Cultural Context ◽  
Big Bang ◽  
Galactic Centre ◽  
Red Giants ◽  
Extraterrestrial Life ◽  
Modern Physics ◽  
Recent Developments ◽  
The Universe

The Cosmic Mystery Tour is a brief account of modern physics and astronomy presented in a broad historical and cultural context. The book is attractively illustrated and aimed at the general reader. Part I explores the laws of physics including general relativity, the structure of matter, quantum mechanics and the Standard Model of particle physics. It discusses recent discoveries such as gravitational waves and the project to construct LISA, a space-based gravitational wave detector, as well as unresolved issues such as the nature of dark matter. Part II begins by considering cosmology, the study of the universe as a whole and how we arrived at the theory of the Big Bang and the expanding universe. It looks at the remarkable objects within the universe such as red giants, white dwarfs, neutron stars and black holes, and considers the expected discoveries from new telescopes such as the Extremely Large Telescope in Chile, and the Event Horizon Telescope, currently aiming to image the supermassive black hole at the galactic centre. Part III considers the possibility of finding extraterrestrial life, from the speculations of science fiction authors to the ongoing search for alien civilizations known as SETI. Recent developments are discussed: space probes to the satellites of Jupiter and Saturn; the discovery of planets in other star systems; the citizen science project SETI@Home; Breakthrough Starshot, the project to develop technologies to send spacecraft to the stars. It also discusses the Fermi paradox which argues that we might actually be alone in the cosmos

Sign in / Sign up

Export Citation Format

Share Document