Tag Archives: Proxima Centauri

Free Astronomy Magazine – July-August 2020 Issue Available For Reading And Download

And Happy 4th, fellow astrophiles!

The most recent issue of Free Astronomy Magazine (July-August 2020) is available for your reading and downloading pleasure at www.astropublishing.com (click the link to go directly to the issue).

July-August 2020 includes a selected survey of astronomical content of local and cosmological interest from NASA/ESA, ESO, ALMA, as well as three feature articles from our fearless leader/editor Michele Ferrara. The feature articles in this issue discuss:

  1. “All the planets of Proxima Centauri” – the science for this article was quite literally being published as the article itself was being put together, about as fast a processing of journal-article-to-magazine as one can do while putting others together.
  2. “A supernova or Sagittarius – which should we thank?” – I’ve mentioned in many lectures that our own Sun is either the second or third stellar inhabitant in our vicinity, with a local supernova sparking the formation of it and our Solar System way back when. Recent studies indicate that other events 5-ish billion years ago might have instigated the events that lead to “us.”
  3. “The principle of mediocrity and the habitability of galaxies” – lump this use of the word “mediocrity” with the scientific use of the word “theory,” please. It is a joy to know that fundamental debates are being had in the astronomy and astrophysics literature and that there remains plenty, plenty yet to know for those pondering their futures in STEM.

For those wanting a quick look at what the issue has to offer, the Table of Contents is reproduced below.

The web browser-readable version: www.astropublishing.com/4FAM2020/

Jump right to the PDF download (15 MB): July-August 2020

Free Astronomy Magazine – May-June 2018 Issue Available For Reading And Download

Greetings, fellow astrophiles!

The most recent issue of Free Astronomy Magazine (May-June 2018) is available for your reading and downloading pleasure at www.astropublishing.com (click the link to go directly to the issue).

Free Astronomy Magazine was featured as the first of a series of articles on great free online content for amateur astronomers (see A Universe Of Free Resources Part 1) and we’ll be keeping track of future publications under the Online Resources category on the CNYO website.

You can find previous Free Astronomy Magazine issues by checking out our Free Astronomy Magazine Category (or look under the Education link in our menu).

For those wanting a quick look at what the issue has to offer, the Table of Contents is reproduced below.

May-June 2018

The web browser-readable version of the issue can be found here:

May-June 2018 – www.astropublishing.com/3FAM2018/

For those who want to jump right to the PDF download (27 MB), Click here: May-June 2018

NASA Space Place – Is Proxima Centauri’s ‘Earth-like’ Planet Actually Like Earth At All?

Poster’s Note: One of the many under-appreciated aspects of NASA is the extent to which it publishes quality science content for children and Ph.D.’s alike. NASA Space Place has been providing general audience articles for quite some time that are freely available for download and republishing. Your tax dollars help promote science! The following article was provided for reprinting in October, 2016.

By Dr. Ethan Siegel

2013february2_spaceplaceJust 25 years ago, scientists didn’t know if any stars—other than our own sun, of course—had planets orbiting around them. Yet they knew with certainty that gravity from massive planets caused the sun to move around our solar system’s center of mass. Therefore, they reasoned that other stars would have periodic changes to their motions if they, too, had planets.

This change in motion first led to the detection of planets around pulsars in 1991, thanks to the change in pulsar timing it caused. Then, finally, in 1995 the first exoplanet around a normal star, 51 Pegasi b, was discovered via the “stellar wobble” of its parent star. Since that time, over 3000 exoplanets have been confirmed, most of which were first discovered by NASA’s Kepler mission using the transit method. These transits only work if a solar system is fortuitously aligned to our perspective; nevertheless, we now know that planets—even rocky planets at the right distance for liquid water on their surface—are quite common in the Milky Way.

On August 24, 2016, scientists announced that the stellar wobble of Proxima Centauri, the closest star to our sun, indicated the existence of an exoplanet. At just 4.24 light years away, this planet orbits its red dwarf star in just 11 days, with a lower limit to its mass of just 1.3 Earths. If verified, this would bring the number of Earth-like planets found in their star’s habitable zones up to 22, with ‘Proxima b‘ being the closest one. Just based on what we’ve seen so far, if this planet is real and has 130 percent the mass of Earth, we can already infer the following:

* It receives 70 percent of the sunlight incident on Earth, giving it the right temperature for liquid water on its surface, assuming an Earth-like atmosphere.

* It should have a radius approximately 10 percent larger than our own planet’s, assuming it is made of similar elements.

* It is plausible that the planet would be tidally locked to its star, implying a permanent ‘light side’ and a permanent ‘dark side’.

* And if so, then seasons on this world are determined by the orbit’s ellipticity, not by axial tilt.

Yet the unknowns are tremendous. Proxima Centauri emits considerably less ultraviolet light than a star like the sun; can life begin without that? Solar flares and winds are much greater around this world; have they stripped away the atmosphere entirely? Is the far side permanently frozen, or do winds allow possible life there? Is the near side baked and barren, leaving only the ‘ring’ at the edge potentially habitable?

Proxima b is a vastly different world from Earth, and could range anywhere from actually inhabited to completely unsuitable for any form of life. As 30m-class telescopes and the next generation of space observatories come online, we just may find out!

Looking to teach kids about exoplanet discovery? NASA Space Place explains stellar wobble and how this phenomenon can help scientists find exoplanets: spaceplace.nasa.gov/barycenter/en/

This article was provided by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

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Caption: An artist’s conception of the exoplanet Kepler-452b (R), a possible candidate for Earth 2.0, as compared with Earth (L). Image credit: NASA/Ames/JPL-Caltech/T. Pyle.

About NASA Space Place

With articles, activities, crafts, games, and lesson plans, NASA Space Place encourages everyone to get excited about science and technology. Visit spaceplace.nasa.gov (facebook|twitter) to explore space and Earth science!

Free Astronomy Magazine – September-October 2016 Issue Available For Reading And Download

Greetings, fellow astrophiles!

2016sept8_freeastroThe most recent issue of Free Astronomy Magazine (September-October, 2016) is available for your reading and downloading pleasure at www.astropublishing.com (click the link to go directly to the issue).

Free Astronomy Magazine was featured as the first of a series of articles on great free online content for amateur astronomers (see A Universe Of Free Resources Part 1) and we’ll be keeping track of future publications under the Online Resources category on the CNYO website.

You can find previous Free Astronomy Magazine issues by checking out our Free Astronomy Magazine Category (or look under the Education link in our menu).

For those wanting a quick look at what the issue has to offer, the Table of Contents is reproduced below.

September-October 2016

The web browser-readable version of the issue can be found here:

September/October 2016 – www.astropublishing.com/FAM-5-2016/index.html

For those who want to jump right to the PDF download (27 MB), Click here: September-October 2016

2016sept8_fam-5-2016-3

NASA Space Place – Is There A Super-Earth In The Solar System Out Beyond Neptune?

Poster’s Note: One of the many under-appreciated aspects of NASA is the extent to which it publishes quality science content for children and Ph.D.’s alike. NASA Space Place has been providing general audience articles for quite some time that are freely available for download and republishing. Your tax dollars help promote science! The following article was provided for reprinting in August, 2016.

By Dr. Ethan Siegel

2013february2_spaceplaceWhen the advent of large telescopes brought us the discoveries of Uranus and then Neptune, they also brought the great hope of a Solar System even richer in terms of large, massive worlds. While the asteroid belt and the Kuiper belt were each found to possess a large number of substantial icy-and-rocky worlds, none of them approached even Earth in size or mass, much less the true giant worlds. Meanwhile, all-sky infrared surveys, sensitive to red dwarfs, brown dwarfs and Jupiter-mass gas giants, were unable to detect anything new that was closer than Proxima Centauri. At the same time, Kepler taught us that super-Earths, planets between Earth and Neptune in size, were the galaxy’s most common, despite our Solar System having none.

The discovery of Sedna in 2003 turned out to be even more groundbreaking than astronomers realized. Although many Trans-Neptunian Objects (TNOs) were discovered beginning in the 1990s, Sedna had properties all the others didn’t. With an extremely eccentric orbit and an aphelion taking it farther from the Sun than any other world known at the time, it represented our first glimpse of the hypothetical Oort cloud: a spherical distribution of bodies ranging from hundreds to tens of thousands of A.U. from the Sun. Since the discovery of Sedna, five other long-period, very eccentric TNOs were found prior to 2016 as well. While you’d expect their orbital parameters to be randomly distributed if they occurred by chance, their orbital orientations with respect to the Sun are clustered extremely narrowly: with less than a 1-in-10,000 chance of such an effect appearing randomly.

Whenever we see a new phenomenon with a surprisingly non-random appearance, our scientific intuition calls out for a physical explanation. Astronomers Konstantin Batygin and Mike Brown provided a compelling possibility earlier this year: perhaps a massive perturbing body very distant from the Sun provided the gravitational “kick” to hurl these objects towards the Sun. A single addition to the Solar System would explain the orbits of all of these long-period TNOs, a planet about 10 times the mass of Earth approximately 200 A.U. from the Sun, referred to as Planet Nine. More Sedna-like TNOs with similarly aligned orbits are predicted, and since January of 2016, another was found, with its orbit aligning perfectly with these predictions.

Ten meter class telescopes like Keck and Subaru, plus NASA’s NEOWISE mission, are currently searching for this hypothetical, massive world. If it exists, it invites the question of its origin: did it form along with our Solar System, or was it captured from another star’s vicinity much more recently? Regardless, if Batygin and Brown are right and this object is real, our Solar System may contain a super-Earth after all.

This article was provided by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

August2016.en

Caption: A possible super-Earth/mini-Neptune world hundreds of times more distant than Earth is from the Sun. Image credit: R. Hurt / Caltech (IPAC)

About NASA Space Place

With articles, activities, crafts, games, and lesson plans, NASA Space Place encourages everyone to get excited about science and technology. Visit spaceplace.nasa.gov (facebook|twitter) to explore space and Earth science!