scholarly journals On the abundance of extraterrestrial life after the Kepler mission

2015 ◽  
Vol 14 (3) ◽  
pp. 511-516 ◽  
Author(s):  
Amri Wandel
Keyword(s):  
Significant Fraction ◽  
Habitable Zone ◽  
Radio Telescopes ◽  
Extraterrestrial Life ◽  
Space Density ◽  
Astronomical Data ◽  
Unknown Probability ◽  
Kepler Mission ◽  
Average Longevity ◽  
Electromagnetic Signals

AbstractThe data recently accumulated by the Kepler mission have demonstrated that small planets are quite common and that a significant fraction of all stars may have an Earth-like planet within their habitable zone. These results are combined with a Drake-equation formalism to derive the space density of biotic planets as a function of the relatively modest uncertainty in the astronomical data and of the (yet unknown) probability for the evolution of biotic life, Fb. I suggest that Fb may be estimated by future spectral observations of exoplanet biomarkers. If Fb is in the range 0.001–1, then a biotic planet may be expected within 10–100 light years from Earth. Extending the biotic results to advanced life I derive expressions for the distance to putative civilizations in terms of two additional Drake parameters – the probability for evolution of a civilization, Fc, and its average longevity. For instance, assuming optimistic probability values (Fb~Fc~1) and a broadcasting longevity of a few thousand years, the likely distance to the nearest civilizations detectable by searching for intelligent electromagnetic signals is of the order of a few thousand light years. The probability of detecting intelligent signals with present and future radio telescopes is calculated as a function of the Drake parameters. Finally, I describe how the detection of intelligent signals would constrain the Drake parameters.

One Step Short of Life

2018 ◽  
Author(s):  
Karel Schrijver
Keyword(s):  
Liquid Water ◽  
Radio Telescopes ◽  
Speed Of Light ◽  
Extraterrestrial Life ◽  
True Nature ◽  
One Step ◽  
New Strategies ◽  
Present Focus

This chapter briefly reviews some the challenges encountered in the search for extraterrestrial life. So far, no signs of extraterrestrial life have been found. The search started with radio telescopes, looking for technology-based civilizations, but new strategies have emerged that take on the primary challenges in this search: the enormous distances to exoplanets and the question of the true nature of life. The author outlines the development of new tools for the search, and why the present focus is on Earth-sized exoplanets with a potential for liquid water on their surfaces. Not having been visited by an alien civilization presents us with a paradox: if life develops as quickly elsewhere as on Earth, then why have we not been contacted? Is the speed of light too slow to cross interstellar distances, is life intrinsically rare, or should we conclude that civilizations are intrinsically short-lived?

scholarly journals Selection Functions in Astronomical Data Modeling, with the Space Density of White Dwarfs as a Worked Example

2021 ◽  
Vol 162 (4) ◽  
pp. 142
Author(s):  
Hans-Walter Rix ◽  
David W. Hogg ◽  
Douglas Boubert ◽  
Anthony G. A. Brown ◽  
Andrew Casey ◽  
...  
Keyword(s):  
White Dwarfs ◽  
Data Modeling ◽  
Space Density ◽  
Astronomical Data ◽  
Worked Example

scholarly journals TheKepler Missionand Eclipsing Binaries

2006 ◽  
Vol 2 (S240) ◽  
pp. 236-243 ◽  
Author(s):  
David Koch ◽  
William Borucki ◽  
Gibor Basri ◽  
Timothy Brown ◽  
Douglas Caldwell ◽  
...  
Keyword(s):  
Eclipsing Binaries ◽  
Light Curves ◽  
Field Of View ◽  
Habitable Zone ◽  
Target List ◽  
Kepler Mission ◽  
Photometric Observations ◽  
Single Field ◽  
Verification Process

AbstractTheKepler Missionis a space-based photometric mission with a differential photometric precision of 14 ppm (atV= 12 for a 6.5 hour transit). It is designed to continuously observe a single field of view (FOV) of greater then 100 square degrees in the Cygnus-Lyra region for four or more years. The primary goal of the mission is to monitor more than one-hundred thousand stars for transits of Earth-size and smaller planets in the habitable zone of solar-like stars. In the process, many eclipsing binaries (EB) will also be detected and light curves produced. To enhance and optimize the mission results, the stellar characteristics for all the stars in theKeplerFOV withV< 16 will have been determined prior to launch. As part of the verification process, stars with transit candidates will have radial-velocity follow-up observations performed to determine the component masses and thereby separate eclipses caused by stellar companions from transits caused by planets. The result will be a rich database on EBs. The community will have access to the archive for further analysis, such as, for EB modeling of the high-precision light curves. A guest observer program is also planned to allow for photometric observations of objects not on the target list but within the FOV.

scholarly journals Kepler mission highlights

2010 ◽  
Vol 6 (S276) ◽  
pp. 34-43 ◽  
Author(s):  
William J. Borucki ◽  
David G. Koch ◽  
Keyword(s):  
Binary Stars ◽  
Variable Stars ◽  
Habitable Zone ◽  
Data Set ◽  
Eclipsing Binary Stars ◽  
The Earth ◽  
Kepler Mission ◽  
Period Orbit ◽  
Short Period ◽  
Data Release

AbstractDuring the first 33.5 days of science-mode operation of the Kepler Mission, the stellar flux of 156,000 stars were observed continuously. The data show the presence of more than 1800 eclipsing binary stars, over 700 stars with planetary candidates, and variable stars of amazing variety. Analyses of the commissioning data also show transits, occultations and light emitted from the known exoplanet HAT-P7b. The depth of the occultation is similar in amplitude to that expected from a transiting Earth-size planet and demonstrates that the Mission has the precision necessary to detect such planets. On 15 June 2010, the Kepler Mission released most of the data from the first quarter of observations. At the time of this data release, 706 stars from this first data set have exoplanet candidates with sizes from as small as that of the Earth to larger than that of Jupiter. More than half the candidates on the released list have radii less than half that of Jupiter. Five candidates are present in and near the habitable zone; two near super-Earth size, one similar in size to Neptune, and two bracketing the size of Jupiter. The released data also include five possible multi-planet systems. One of these has two Neptune-size (2.3 and 2.5 Earth-radius) candidates with near-resonant periods as well as a super-Earth-size planet in a very short period orbit.

scholarly journals The science of EChO

2010 ◽  
Vol 6 (S276) ◽  
pp. 359-370 ◽  
Author(s):  
Giovanna Tinetti ◽  
James Y-K. Cho ◽  
Caitlin A. Griffith ◽  
Olivier Grasset ◽  
Lee Grenfell ◽  
...  
Keyword(s):  
Solar System ◽  
Emission Spectroscopy ◽  
European Space Agency ◽  
Habitable Zone ◽  
The Past ◽  
Space Agency ◽  
Kepler Mission ◽  
The Galaxy ◽  
Earth Like Planets ◽  
Exoplanetary Atmospheres

AbstractThe science of extra-solar planets is one of the most rapidly changing areas of astrophysics and since 1995 the number of planets known has increased by almost two orders of magnitude. A combination of ground-based surveys and dedicated space missions has resulted in 560-plus planets being detected, and over 1200 that await confirmation. NASA's Kepler mission has opened up the possibility of discovering Earth-like planets in the habitable zone around some of the 100,000 stars it is surveying during its 3 to 4-year lifetime. The new ESA's Gaia mission is expected to discover thousands of new planets around stars within 200 parsecs of the Sun. The key challenge now is moving on from discovery, important though that remains, to characterisation: what are these planets actually like, and why are they as they are?In the past ten years, we have learned how to obtain the first spectra of exoplanets using transit transmission and emission spectroscopy. With the high stability of Spitzer, Hubble, and large ground-based telescopes the spectra of bright close-in massive planets can be obtained and species like water vapour, methane, carbon monoxide and dioxide have been detected. With transit science came the first tangible remote sensing of these planetary bodies and so one can start to extrapolate from what has been learnt from Solar System probes to what one might plan to learn about their faraway siblings. As we learn more about the atmospheres, surfaces and near-surfaces of these remote bodies, we will begin to build up a clearer picture of their construction, history and suitability for life.The Exoplanet Characterisation Observatory, EChO, will be the first dedicated mission to investigate the physics and chemistry of Exoplanetary Atmospheres. By characterising spectroscopically more bodies in different environments we will take detailed planetology out of the Solar System and into the Galaxy as a whole.EChO has now been selected by the European Space Agency to be assessed as one of four M3 mission candidates.

scholarly journals Flares from ultracool L dwarfs with Kepler

2015 ◽  
Vol 11 (S320) ◽  
pp. 153-154
Author(s):  
John E. Gizis ◽  
Rishi Paudel ◽  
Peter K. G. Williams ◽  
Adam J. Burgasser ◽  
Sarah J. Schmidt
Keyword(s):  
White Light ◽  
Habitable Zone ◽  
Dwarf Stars ◽  
Kepler Mission ◽  
L Dwarfs ◽  
M Dwarf

AbstractWe report on our search for L dwarf flares using NASA's Kepler mission. Spectroscopically confirmedflares were detected with the original Kepler mission from an L1 dwarf stars. We discuss the physicalcharacteristics of these white light flares and compare them to M dwarf flares. For “habitable zone” planets, the apparent flare brightnesses would be comparable to the most powerful M dwarf flares. Weare monitoring more L dwarfs with the Kepler K2 mission. We discussthe prospect for more detections during the remainder of the K2 mission.

Steps towards eta-Earth, from Kepler data

2014 ◽  
Vol 14 (3) ◽  
pp. 359-363 ◽  
Author(s):  
Wesley A. Traub
Keyword(s):  
Region Of Interest ◽  
Analytical Form ◽  
Terrestrial Planets ◽  
Model Parameters ◽  
Habitable Zone ◽  
Underlying Distribution ◽  
Habitable Zones ◽  
Kepler Mission ◽  
Instrument Noise ◽  
Minimal Bias

AbstractThe goal of this paper is to take steps towards estimating the frequency of terrestrial planets in the habitable zones of their host stars, using planet counts from the Kepler mission. The method is to assume that an analytical form for the underlying distribution function, numerically simulate the observing procedure, compare the simulated and real observations, and iterate the model parameters to achieve convergence in the sense of least-squares. The underlying distribution can then be extrapolated to a region of interest, here the terrestrial habitable-zone range. In this regime (small radii, long periods), the instrument noise makes such detections essentially impossible below a fairly sharply defined threshold signal level. This threshold can be estimated from the existing data. By taking this cutoff into account, the distribution of planets, as a function of radius and period, can be estimated with minimal bias. Extending this distribution to terrestrial planets in habitable-zone orbits can yield an estimate of eta-sub-Earth.

scholarly journals Building a VO-compliant Radio Astronomical DAta Model for Single-dish radio telescopes (RADAMS)

2012 ◽  
Vol 34 (3) ◽  
pp. 623-652 ◽  
Author(s):  
Juan de Dios Santander-Vela ◽  
Emilio García ◽  
Stephane Leon ◽  
Victor Espigares ◽  
José Enrique Ruiz ◽  
...  
Keyword(s):  
Data Model ◽  
Radio Telescopes ◽  
Astronomical Data

scholarly journals Detecting Distant Planets with Space Telescope

1985 ◽  
Vol 112 ◽  
pp. 85-89
Author(s):  
Thornton Page
Keyword(s):  
Graduate Students ◽  
Significant Fraction ◽  
Research Projects ◽  
Life Space ◽  
Extraterrestrial Life ◽  
Space Telescope ◽  
Science Institute ◽  
University Of Houston ◽  
Scientists And Engineers ◽  
The University

In 1981 and in 1984, I offered at the University of Houston, CLC, a course on Space Telescope, the first of its kind. The 22 graduate students were assigned research projects of their own choosing designed for ST. Several chose the detection of planets of other stars, showing the popularity of the search for extraterrestrial life. Space Telescope's six instruments can be used for this purpose in several ways, and the students, most of them scientists and engineers at the NASA Johnson Space Center, proposed to use most of these after ST is launched in 1986 or 1987. The student proposals require a significant fraction of ST observing time over a period of five to ten years, indicating the over-subscription that faces the ST Science Institute. In this paper, I summarize the capability of ST instruments, and recount the techniques likely to be most effective in using them to detect planets of other stars.

scholarly journals A Step Toward Eta-sub-Earth

2012 ◽  
Vol 8 (S293) ◽  
pp. 84-87
Author(s):  
Wesley A. Traub
Keyword(s):  
Type Star ◽  
Terrestrial Planets ◽  
Habitable Zone ◽  
Reaction Wheel ◽  
Expected Number ◽  
Initial Examination ◽  
True Value ◽  
Kepler Mission ◽  
Solar Type ◽  
Solar Type Star

AbstractThe Kepler mission observed exoplanet transits for 4 full years (greater than its expected lifetime of 3.5 years) until it became inoperable for its original purpose, as a result of a reaction wheel failure. Kepler was spectacularly successful in its goal of observing exoplanet transits of host star disks for the purpose of measuring the statistics of such transits in its target star sample. The Kepler data, when fully analyzed, will determine the statistics of planets in the underlying population, and in particular the expected number of terrestrial planets in habitable zone orbits per solar-type star, the quantity known as eta-sub-Earth. This report is an initial examination of Kepler's third catalog (Feb. 2012) of planets and candidate planets. I find that the apparent projected value of eta-sub-Earth is several times smaller than I had found from the second catalog, but that the data are now approaching the point where intrinsic biases can be uncovered. When all bias factors are eventually found, it is likely that the true value of eta-sub-Earth will be substantially greater than its current apparent value.

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