Multiplanet system around sunlike star photographed for 1st time ever

rod

Oct 22, 2019
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The space.com report stated, "The two planets are huge and farflung. TYC 8998-760-1b is about 14 times more massive than Jupiter and orbits at an average distance of 160 astronomical units (AU), and TYC 8998-760-1c is six times heftier than Jupiter and lies about 320 AU from the host star. (One AU is the average Earth-sun distance — about 93 million miles, or 150 million kilometers. For comparison: Jupiter and Saturn orbit our sun at just 5 AU and 10 AU, respectively.) It's unclear whether the two worlds in TYC 8998-760-1 formed at their present locations or were pushed out there somehow. Further observations, including those made by huge future observatories such as the European Extremely Large Telescope (ELT), could help to solve that mystery, study team members said."

This is an important comment. Exoplanets that are large and orbiting far from their host stars, are very difficult and challenging to fit into the protoplanetary and accretion disk model(s ) in use. I ran a MS SQL query and found 70 such exoplanets documented now, most are direct imaging detection. Their semi-major axies > 50 AU. See http://exoplanet.eu/
 

Hammer

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I understand the ooo and aaaahhh factor of the giants, but what about the smaller ones? any in the habitable zone?
 
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This is an important comment. Exoplanets that are large and orbiting far from their host stars, are very difficult and challenging to fit into the protoplanetary and accretion disk model(s ) in use.
Yes, it is odd. Since stars come from clouds that allow for up to over 1 million stars to form, perhaps encounters with a close neighbor allowed some planet exchanges or captures. Otherwise, it seems unlikely that this star's accretion disk would allow any very large planet to either form that far out or find some way to get kicked out that far.
 
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rod

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FYI, post #3 asks a good question. From my exoplanet studies, it seems TRAPPIST-1 system is the most reported, exoplanet solar system that may have some exoplanets in the habitable zone. The host star however is a red dwarf, about 0.08 solar masses, very small compared to our Sun. The most recent reports show efforts to document atmospheres on some of these exoplanets, some may not have any atmosphere. Do the TRAPPIST-1 planets have atmospheres?, https://phys.org/news/2020-07-trappist-planets-atmospheres.html

My observation, at the present, it does not seem that TRAPPIST-1 seven exoplanets can be confirmed as having an earth like atmosphere and some may not have any atmosphere, note *(if present)* in the report.
 

Wolfshadw

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Ref: Post #3

Given the sizes and distances in comparison to our system I would not expect to be able to view the inner planets (if any). The CG simulation shows just how far outside the orbit of Pluto these planets would exist in our system

Our habitable zone only extends out approx. 1.4AU. Pluto is approx. 39.5AU. These planets are 4x and 8x more distant from it's star than Pluto is from our Sun.

-Wolf sends
 
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The inability to see planets with < 1 AU orbits limits our ability to understand what is happening. If those very distant outer planets formed that far out, what are the chances there are any inner planets? I would think the odds are more against it than for it.

If, however, the outer planets were captured, then inner planets are certainly possible, but serious stellar interactions will also limit planets that are beyond, say, Jupiter or Saturn due to disruption by the passing star(s).

This and other things puts the upper limit on the number our Sun had for neighbors to about 3000 stars. The IMF (Initial Mass Function) demonstrates that, likely, a few of these would have been massive stars, which form early and brightly, perhaps illuminating our disk if one or more were relatively close.
 
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rod

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FYI all. I went back and reviewed some reports I in my home database on multiple giant planets reported in the news recently. The space.com report here on exoplanets TYC 8998-760-1b and TYC 8998-760-1c, shows the first, multiple giant planet system that is directly imaged now (very cool, I like imaged binary stars and exoplanets). The host or parent star is 1 solar mass and said to be about 17E+6 years old, a very young solar analog star according to stellar evolution theory.

We have other reports of multiple giant planets, these are not imaged (primary transit and radial velocity detections). WASP-148 (example, http://exoplanet.eu/catalog/wasp-148_b/) and Kepler-88 system, (http://exoplanet.eu/catalog/kepler-88_b/ as an example). These are more like hot jupiters or warm Neptunes, orbiting very close to their host stars with host star masses near one solar mass too. Kepler-88 host star is considered to be about 2.45E+9 years old . Kepler-88 and WASP-148 multiple giant exoplanet systems all orbit their host stars much closer than 1 AU compared to the TYC 8998-760-1 system imaged.

Consider a collapsing gas cloud and protoplanetary accretion disk model(s). We have our solar system configuration with a one solar mass star and a very habitable Earth. Now we see multiple giant exoplanets imaged around a star about one solar mass much farther away, and other multiple giant planets detected, orbiting around their host stars much closer than Mercury's orbit in our solar system. Those collapsing gas clouds work wonders in planet formation, considering the exoplanet varieties reported now :)
 
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Do you see anything from the data of distant giants AND close smaller terrestrial planets? [Not that it would be easy for astronomers to see such things as distant orbits are extremely unlikely in number for transits and weak in spectral shifts.]
 
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rod

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Helio, your question in #10 post. No I did not see reports of multiple giant planet systems with smaller terrestrial planets. However, I have not done a deep dive here :) This exoplanet site, http://exoplanet.eu/catalog/, lists 4296 confirmed and 702 host stars are reported as multiple planet systems, i.e. 2 or more exoplanets found orbiting the host star. These 3 host stars show 7-8 exoplanets orbiting them, star_name HD 219134, Kepler-90, and TRAPPIST-1.

Here is another exoplanet site I use, https://exoplanetarchive.ipac.caltech.edu/index.html, 4183 confirmed. This site reports 706 host stars with multiple exoplanets. The host stars with 6-8 exoplanets orbiting them are: pl_hostname, HD 10180, HD 219134, HD 34445, Kepler-11, Kepler-20, Kepler-80, KOI-351, TRAPPIST-1.

Both sites I use and load into my home MS ACCESS database for MS SQL queries and reports. There is plenty of exoplanets now for deep dives and much fun studying---Rod
 
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Helio, your question in #10 post. No I did not see reports of multiple giant planet systems with smaller terrestrial planets. However, I have not done a deep dive here :) This exoplanet site, http://exoplanet.eu/catalog/, lists 4296 confirmed and 702 host stars are reported as multiple planet systems, i.e. 2 or more exoplanets found orbiting the host star. These 3 host stars show 7-8 exoplanets orbiting them, star_name HD 219134, Kepler-90, and TRAPPIST-1.

Here is another exoplanet site I use, https://exoplanetarchive.ipac.caltech.edu/index.html, 4183 confirmed. This site reports 706 host stars with multiple exoplanets. The host stars with 6-8 exoplanets orbiting them are: pl_hostname, HD 10180, HD 219134, HD 34445, Kepler-11, Kepler-20, Kepler-80, KOI-351, TRAPPIST-1.
Yep. It's been a while since I used either of them. About 15 years ago, I started plotting the number discovered per year and extrapolated into the numbers we see today. [I can't find any of those graphs, however.:) ]

Remind me why the EU version states M-Jupiter / M-Earth. Don't they just mean the M-Jupiter mass? If not, what do they do to distinguish between the two. I don't see M-Earth used in the Caltech catalog.

I understand, well enough, the sin(i) function used for some.
 
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rod

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"Remind me why the EU version states M-Jupiter / M-Earth. Don't they just mean the M-Jupiter mass? If not, what do they do to distinguish between the two. I don't see M-Earth used in the Caltech catalog."

Helio, the EU site allows you to switch the mass value between Jupiter masses and earth masses on the column for 'Mass'. Example, http://exoplanet.eu/catalog/, searching for PSR 1257 12 b, you can see the value differences. 0.00007 Mjup or 0.022 earth masses. In my home database, I convert and use both masses stored in my table including Mass*sin(i). I find it useful to perform MS SQL joins and compare data between the two sites, matched and unmatched queries, etc as well as develop my own reports. Also I find it very useful to review when various exoplanet reports are published in the popular science sites, e.g. space.com :)
 
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rod

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Sam in #16. The arcsecond for these two imaged giant exoplanets (TYC 8998-760-1b and TYC 8998-760-1c) at 95 pc distance from Earth, about 1.7" to 3.4" angular separation from the parent star for the AU reported (160 to 320 AU from the star). The two exoplanet reference sites I mention in post #11 show how many are confirmed and imaged now. The EU site shows 140 exoplanets imaged and the caltech site shows 50. The imaged exoplanets are large in size and orbit far from their parent stars too, that is expected if the exoplanets can be seen in visual light or infrared and imaged, especially when considering their arcsecond angular separation from the parent stars and different distances for them.
 
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The problem is that red dwarf stars are far more active than a Sun-sized star in it's main sequence. The surface of any exo planets orbiting one may be periodically scorched by radiation and flairs.

I am so amazed at these pictures though. Every time I see one I almost tear up. I have been waiting about 50 years to see photos like these. I only hope we can get some serious images even more resolved before I have to pass "beyond the rim".
 

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