Astronomy

[Danik 2016]

'Monster' planet discovery challenges formation theory
Date:
October 31, 2017
Source:
Royal Astronomical Society
Summary:
A giant planet, which should not exist according to planet formation theory, has been discovered around a distant star.

"The existence of the 'monster' planet, 'NGTS-1b', challenges theories of planet formation which state that a planet of this size could not be formed around such a small star. According to these theories, small stars can readily form rocky planets but do not gather enough material together to form Jupiter-sized planets."

https://www.sciencedaily.com/release...1031105158.htm

[Dreamwoven]

Yes, this was interesting. The original post can be found here:
https://www.universetoday.com/137706...ary-formation/

"If this “wobbling” is not an unknown astrophysical phenomenon and in fact the result of the behaviour of dark matter, then it is inconsistent with the standard model of dark matter and can only be explained if dark matter particles can interact with each other – a strong contradiction to the current understanding of dark matter. This may indicate that new fundamental physics is required to solve the mystery of dark matter."

https://astronomynow.com/2017/10/26/...ling-galaxies/[/QUOTE]

[Dreamwoven]

https://www.universetoday.com/137706...ary-formation/

Some basic truths are starting to be questioned...

[Dreamwoven]

https://www.universetoday.com/137736...restrial-life/

"Despite the thousands of exoplanets that have been discovered by astronomers in recent years, determining whether or not any of them are habitable is a major challenge. Since we cannot study these planets directly, scientists are forced to look for indirect indications. These are known as biosignatures, which consist of the chemical byproducts we associate with organic life showing up in a planet’s atmosphere.

A new study by a team of NASA scientists proposes a new method to search for potential signs of life beyond our Solar System. The key, they recommend, is to takes advantage of frequent stellar storms from cool, young dwarf stars. These storms hurl huge clouds of stellar material and radiation into space, interacting with exoplanet atmospheres and producing biosignatures that could be detected."

[Danik 2016]

The first sign of exoplanets?
Overlooked Treasure: The First Evidence of Exoplanets
Date:
November 1, 2017
Source:
NASA/Jet Propulsion Laboratory
Summary:
Mount Wilson is the site where some of the key discoveries about our galaxy and universe were made in the early 20th century. But there is a far lesser known, 100-year-old discovery from Mount Wilson -- one that was unidentified and unappreciated until recently: the first evidence of exoplanets.
"A detective story

It started with Ben Zuckerman, professor emeritus of astronomy at the University of California, Los Angeles. He was preparing a talk about the compositions of planets and smaller rocky bodies outside our solar system for a July 2014 symposium at the invitation of Jay Farihi, whom he had helped supervise when Farihi was a graduate student at UCLA. Farihi had suggested that Zuckerman talk about the pollution of white dwarfs, which are faint, dead stars composed of mainly hydrogen and helium. By "pollution," astronomers mean heavy elements invading the photospheres -- the outer atmospheres -- of these stars. The thing is, all those extra elements shouldn't be there -- the strong gravity of the white dwarf should pull the elements into the star's interior, and out of sight.

The first polluted white dwarf identified is called van Maanen's Star (or "van Maanen 2" in the scientific literature), after its discoverer Adriaan van Maanen. Van Maanen found this object in 1917 by spotting its subtle motion relative to other stars between 1914 and 1917. Astronomer Walter Sydney Adams, who would later become director of Mount Wilson, captured the spectrum -- a chemical fingerprint -- of van Maanen's Star on a small glass plate using Mount Wilson's 60-inch telescope. Adams interpreted the spectrum to be of an F-type star, presumably based on the presence and strength of calcium and other heavy-element absorption features, with a temperature somewhat higher than our Sun. In 1919, van Maanen called it a "very faint star."

Today, we know that van Maanen's Star, which is about 14 light-years away, is the closest white dwarf to Earth that is not part of a binary system.

"This star is an icon," Farihi said recently. "It is the first of its type. It's really the proto-prototype."

While preparing his talk, Zuckerman had what he later called a "true 'eureka' moment." Van Maanen's Star, unbeknownst to the astronomers who studied it in 1917 and those who thought about it for decades after, must be the first observational evidence that exoplanets exist."

https://www.sciencedaily.com/release...1101175446.htm

[Dreamwoven]

https://www.universetoday.com/137706...ary-formation/

Some basic truths are starting to be questioned...

When it comes to how and where planetary systems form, astronomers thought they had a pretty good handle on things. The predominant theory, known as the Nebular Hypothesis, states that stars and planets form from massive clouds of dust and gas (i.e. nebulae). Once this cloud experiences gravitational collapse at the center, its remaining dust and gas forms a protoplanetary disk that eventually accretes to form planets.

However, when studying the distant star NGTS-1 – an M-type (red dwarf) located about 600 light-years away – an international team led by astronomers from the University of Warwick discovered a massive “hot Jupiter” that appeared far too large to be orbiting such a small star. The discovery of this “monster planet” has naturally challenged some previously-held notions about planetary formation.

[Dreamwoven]

https://www.universetoday.com/137739...ife-enceladus/

Ever since the Cassini mission entered the Saturn system and began studying its moons, Enceladus has become a major source of interest. Once the probe detected plumes of water and organic molecules erupting from the moon’s southern polar region, scientists began to speculate that Enceladus may possess a warm-water ocean in its interior – much like Jupiter’s moon Europa and other bodies in our Solar System.

In the future, NASA hopes to send another mission to this system to further explore these plumes and the interior of Enceladus. This mission will likely include a new instrument that was recently announced by NASA, known as the Submillimeter Enceladus Life Fundamentals Instrument (SELFI). This instrument, which was proposed by a team from the NASA Goddard Space Flight Center, recently received support for further development.

[Dreamwoven]

https://astronomynow.com/2017/10/14/...ntists-report/

Titan, the largest of Saturn’s more than 60 moons, has surprisingly intense rainstorms, according to research by a team of UCLA planetary scientists and geologists. Although the storms are relatively rare — they occur less than once per Titan year, which is 29 and a half Earth years — they occur much more frequently than the scientists expected.

“I would have thought these would be once-a-millennium events, if even that,” said Jonathan Mitchell, UCLA associate professor of planetary science and a senior author of the research, which was published Oct. 9 in the journal Nature Geoscience. “So this is quite a surprise.”

[Danik 2016]

When it comes to how and where planetary systems form, astronomers thought they had a pretty good handle on things. The predominant theory, known as the Nebular Hypothesis, states that stars and planets form from massive clouds of dust and gas (i.e. nebulae). Once this cloud experiences gravitational collapse at the center, its remaining dust and gas forms a protoplanetary disk that eventually accretes to form planets.

However, when studying the distant star NGTS-1 – an M-type (red dwarf) located about 600 light-years away – an international team led by astronomers from the University of Warwick discovered a massive “hot Jupiter” that appeared far too large to be orbiting such a small star. The discovery of this “monster planet” has naturally challenged some previously-held notions about planetary formation.

Interesting links, DW. I`ll come back for a closer reading after breakfast.
Anyway it looks as if the current stage of astronomy is one more of new discoveries than one of definite conclusions.

[Dreamwoven]

I agree there is very little about which we can draw definite conclusions. The last week has been particularly poor in that respect.

[Danik 2016]

A very interesting feature of Astronomy is the comparative method, which in your last links refers to wheater. Who would have thought two decades ago that it would be able to compare the weather on distant moons?

[Dreamwoven]

Good point, Danik. We take such things for granted.

[Dreamwoven]

Another query. I don't understand the carnival of space item: https://www.universetoday.com/137741...l-space-532-2/

[Danik 2016]

I suppose its this:
"If you run a space/astronomy related blog, and would like to get more awareness, participate in the Carnival of Space. Every week, a different webmaster or blogger hosts the carnival, showcasing articles written on the topic of space. It’s a great way to get to know the community, and to help your writing reach a wider audience. If you’d like to be a host for the carnival, please send email to [email protected]" Its followed by several topics.

https://www.universetoday.com/12019/carnival-of-space/

[Dreamwoven]

OK, thanks, that was similar to my impression.