Record-breaking alien planet spotted circling massive, superhot star duo (photo)

[Admin]

An exoplanet 11 times more massive than Jupiter resides in b Centauri, a young binary star system about 325 light-years from Earth, a new study reports.

Record-breaking alien planet spotted circling massive, superhot star duo (photo) : Read more

 

[Helio]

This is another rare direct image of an exoplanet and it is of a planet that is 550AU from the binary! At that distance, reflected light is very weak.

But the primary (b Centauri A), as the article states, is about 18,000K, so being a little more than 3x hotter. It's also a B2.5V class star, so it should have a also about 3x that of the Sun.

Temperature increases luminosity to the 4th power, and radius by the square.

Thus this star should be about 100x that of the Sun, allowing for much better illumination of the large planet.

This seems to be the paper.

The paper calls the planet “b Cen (AB)b" , where the "AB" reveals the planet orbits outside the binary. This may be the official way of presenting planets orbiting outside, but if not, it probably should be.

 

[rod]

I note near the end of the report, "This top-down model requires that the mass of the protoplanetary disk be so large that it causes part of the disk to collapse in on itself under the pull of its own gravity. When this happens, a small secondary body is created and starts to orbit the star," Kaitlin Kratter, of the University of Arizona's Steward Observatory, wrote in an accompanying "News and Views" piece in the same issue of Nature. "The gravitational-instability mechanism also tends to create objects that are very large — so large, in fact, that they fail to become planets," added Kratter, who is not a member of the study team. "Compared with the stars it orbits, this planet is small, making gravitational instability less likely than core accretion. Perhaps it is just a planet similar to Jupiter, flung out to the far reaches of its stellar system through an interaction with the stars it orbits. A broad census of planets associated with large stars will help to clarify the exact mechanism of its formation."

Large exoplanets orbiting far from their host stars are documented at the exoplanet sites and imaged too. Just plugging in the 550 au for a, e=0, exoplanet mass = 11 Mjup, host star mass = 1 solar, I get an orbital period more than 12800 years. Using the MMSN, a postulated protoplanetary disk mass could be 3330 earth masses. However, the 11 Mjup exoplanet is nearly 3500 earth masses, far from the parent star. Interesting juggling here to explain such an exoplanet origin.

 

[rod]

Helio's link post #2 says this about the star mass, "Here we demonstrate the existence of a planet at 560 times the Sun-Earth distance from the 6—10 solar mass binary b Centauri through direct imaging."

Using 7 solar mass host star, the MMSN suggests protoplanetary disk mass more than 23000 earth masses with an orbital period perhaps 5000 years or a bit longer for the exoplanet now.

 

[Helio]

Large exoplanets orbiting far from their host stars are documented at the exoplanet sites and imaged too.

The farthest one I see is only 200 AU. Are there others listed that are farther out?

Just plugging in the 550 au for a, e=0, exoplanet mass = 11 Mjup, host star mass = 1 solar, I get an orbital period more than 12800 years.

Yes, but the period will be reduced with greater mass for the host star. Here's the equation, though m can be set to 0.

a^3/T^2 = G(M+m)/(4*pi^2)

So for a 10 Sol mass binary, the period would be about 5,600 years, FWIW. But they likely don't know the eccentricity so if it happens to be near periapsis or apoapsis then this period will change. Given the margin of error, it may be decades to get something close to an accurate period, I would guess.

Using the MMSN, a postulated protoplanetary disk mass could be 3330 earth masses. However, the 11 Mjup exoplanet is nearly 3500 earth masses, far from the parent star. Interesting juggling here to explain such an exoplanet origin.

Yes, but I suspect there are more than one way this can happen based on current models. Discovering more will be helpful of course, especially if they are found in their protostellar phase.

It is interesting that we have a large planet at a distance about what Brown has predicted for our new hypothetical 9th planet.

 

[rod]

Helio, post #5 asks, "The farthest one I see is only 200 AU. Are there others listed that are farther out?"

Yes, example, S Ori 68, directly imaged at 1700 au, The Extrasolar Planet Encyclopaedia — S Ori 68 (exoplanet.eu)

USco 1621A b, directly imaged at 2270 au, The Extrasolar Planet Encyclopaedia — USco 1621A b (exoplanet.eu)

The site I show lists 156 directly imaged exoplanets, a number are very far away from their host stars. Some of those are moving around red dwarf stars. This site lists 54 imaged exoplanets, NASA Exoplanet Archive (caltech.edu)

Some of those exoplanets are at 7506 au from their host star, COCONUTS-2 b

Seems we have plenty to chew on in exoplanet studies now

 

[rod]

Helio et al. After reading different reports on this exoplanet find, for me the take away is a massive star with imaged exoplanet found in a binary system far away from the parent star some 6 to 10 solar masses perhaps. Some of the examples I cited are single stars with much smaller masses. A number of directly imaged exoplanets are documented with distances ranging in the hundreds of au from their stars. Here is another report on this find. Very Large Telescope images planet around most massive star pair to date (phys.org)

I point out this system is about 100 pc so 5 arcsecond angular resolution at the star is 500 au. Something that can be imaged

 

[Helio]

Helio, post #5 asks, "The farthest one I see is only 200 AU. Are there others listed that are farther out?"

Yes, example, S Ori 68, directly imaged at 1700 au, The Extrasolar Planet Encyclopaedia — S Ori 68 (exoplanet.eu)

USco 1621A b, directly imaged at 2270 au, The Extrasolar Planet Encyclopaedia — USco 1621A b (exoplanet.eu)

The site I show lists 156 directly imaged exoplanets, a number are very far away from their host stars. Some of those are moving around red dwarf stars. This site lists 54 imaged exoplanets, NASA Exoplanet Archive (caltech.edu)

Some of those exoplanets are at 7506 au from their host star, COCONUTS-2 b

Seems we have plenty to chew on in exoplanet studies now

Yes. When I used their catalog and selected distance (a) I, oddly, got a different result. It works fine now, apparently.

 

[Helio]

Helio et al. After reading different reports on this exoplanet find, for me the take away is a massive star with imaged exoplanet found in a binary system far away from the parent star some 6 to 10 solar masses perhaps. Some of the examples I cited are single stars with much smaller masses. A number of directly imaged exoplanets are documented with distances ranging in the hundreds of au from their stars. Here is another report on this find. Very Large Telescope images planet around most massive star pair to date (phys.org)

I point out this system is about 100 pc so 5 arcsecond angular resolution at the star is 500 au. Something that can be imaged

The ability to see planets with large orbits is greatly limited to luminous stars and large planets. Keep in mind even the HST cannot observe a Jupiter at about 10,000 AU from us, but it can see an exoplanet at 1 million AU with enough reflective light.

Better scopes are coming.

 

[rod]

Helio, et al. Here is another report on this very interesting exoplanet report. Giant Planet Imaged Around Massive Star - Sky & Telescope - Sky & Telescope (skyandtelescope.org), "The duo, which have a total mass of at least six Suns"

The 6 to 10 solar masses is the sum of the masses for the binary stars, something I learned last night when reading and reviewing more. I do not have the breakout for specifics so just illustrate using this example.

My note, b Centauri binary system, the sum of the masses is 6 to 10 solar mass, not the mass of a single star in the binary system. Using 7 solar mass star and 0.2 solar mass star, a=1000 au, P=1.0536E+04 years or 10,536 years. A 4 solar mass and 6 solar mass binary system with a = 20 au, P about 7 years. Okay, square root here so < 15,000 second period.

 

[Helio]

I note near the end of the report, "This top-down model requires that the mass of the protoplanetary disk be so large that it causes part of the disk to collapse in on itself under the pull of its own gravity. When this happens, a small secondary body is created and starts to orbit the star," Kaitlin Kratter, of the University of Arizona's Steward Observatory, wrote in an accompanying "News and Views" piece in the same issue of Nature. "The gravitational-instability mechanism also tends to create objects that are very large — so large, in fact, that they fail to become planets," added Kratter, who is not a member of the study team.

Yes, and most star systems have more than one star.

But I find this interesting in the paper, that I missed in my typical cusory-only read of these complicated papers:

"Earlier studies of planets in close-in orbits around high-mass stars have revealed an increase in giant planet frequency with increasing stellar mass until a turnover point at 1.9 solar masses, above which the frequency rapidly decreases . This could potentially imply that planet formation is impeded around more massive stars, and that giant planets around stars exceeding 3 solar masses may be rare or non-existent."

It's known that very massive stars form much quicker, perhaps too fast for planets even in a more massive disk. But this seems unlikely to me for stellar masses of only 3 Sols.

Large exoplanets orbiting far from their host stars are documented at the exoplanet sites and imaged too. Just plugging in the 550 au for a, e=0, exoplanet mass = 11 Mjup, host star mass = 1 solar, I get an orbital period more than 12800 years. Using the MMSN, a postulated protoplanetary disk mass could be 3330 earth masses. However, the 11 Mjup exoplanet is nearly 3500 earth masses, far from the parent star. Interesting juggling here to explain such an exoplanet origin.

The nascent disk would have been in the millions of earth masses, so I'm unclear what you're saying here. Typically, IIRC, only about 10% of the natal fragmented cloud would collapse into the protostar.

The paper does suggest some individual masses for the binary:

"...as a dominant star in the system leads to a mass of 6 solar masses, while the second edge 2 case gives individual masses for b Cen A and B of 5.6 and 4.4 solar masses respectively; i.e., a total system mass of 10 solar masses."

Any idea what "edge" means here?

 

[rod]

Helio, ref your post #11. I am not sure where you get the MMSN protoplanetary disk for our Sun as originally in the *millions of earth masses*. Today we see about 447 earth masses from Mercury to Pluto. Most MMSN disk masses for our early Sun are much smaller,
All sources science Query accretion disks

Publication
Minimum Mass Solar Nebulae and Planetary Migration The Minimum Mass Solar Nebula (MMSN) is a protoplanetary disk that contains the minimum amount of solids necessary to build the planets of the solar system. Assuming that the giant planets formed in the compact configuration they have at the beginning of the "Nice model," Desch built a new MMSN... ui.adsabs.harvard.edu

about 3300 earth masses. Concerning the paper ref to *second edge* I do not know. However, I corrected my spreadsheet for calculating the sum of masses in a binary star system and semi-major axis showing orbital period. For this case, M1=5.6 and M2=4.4 solar masses. I plugged in a=1000 au, P=10,000 years. If the binary stars are much closer the period gets much shorter too.

 

[rod]

Evolution of the Solar Nebula. II. Thermal Structure during Nebula Formation

Models of the thermal structure of protoplanetary disks are required for understanding the physics and chemistry of the earliest phases of planet formation. Numerical hydrodynamical models of the protostellar collapse phase have not been evolved far enough in time to be relevant to planet...

ui.adsabs.harvard.edu

This report from 1993 indicates only about 7,000 earth masses used in early simulations from the Sun out to about 10 au. MMSN needs specific boundaries and mass, solids and gas. Better definitions for mass, gas, solids is needed here for the MMSN and clearly presented to the public

 

[Helio]

Thanks Rod.

It's interesting that the model addressed is different with the Hayashi model by a factor of 10. That's a lot of difference, so models may have far to got to refine things.

MMSM model comparison with solar planets shows some big variation in that particular MMSM model.

IIRC, and I could be getting this wrong, only about 1% of typical solar natal nebulae consists of dust, the rest is gas. The heaveier elements of dust require a number of factors like SN and processes nuclear byproducts from nearby stars, especially massive ones. So I would suspect each cloud fragment to be different from one another, though a general view might be adequate for Pop I star systems.

It's interesting to me, espeically, that our solar accretion disk may have been blessed with more metals, as the graph demonstrates, perhaps spewed from locally massive stars. A few relatively massive stars nearby would have been luminous enough, especially in blue light, to illuminate the disk to a blue color to a human's eye, perhaps.

 

[rod]

FYI, another report popped up about another giant planet found far from its parent star, previously not detected. Giant planets forming far away from their parent stars is challenging

Citizen scientists find young-Jupiter-like object missed by previous exoplanet searches, https://phys.org/news/2021-12-citizen-scientists-young-jupiter-like-previous-exoplanet.html

Reference paper, A Wide Planetary Mass Companion Discovered through the Citizen Science Project Backyard Worlds: Planet 9, https://iopscience.iop.org/article/10.3847/1538-4357/ac2499, 09-Dec-2021.

My observation. The NASA ADS Abstract, A Wide Planetary Mass Companion Discovered Through the Citizen Science Project Backyard Worlds: Planet 9, https://ui.adsabs.harvard.edu/abs/2021arXiv211204678F/abstract, December 2021. I note that 37 arcsecond resolution = 1662 au, indicates the distance is some 45 pc from Earth. The 22 page arXiv paper near the end (page 18), "Table 1. Measured Parameters" list the distance as 44.957 pc. The exoplanet listed as 15 Mjup = 4.7673E+03 earth masses or nearly 4800 earth masses. The host star is 1 solar mass so applying the MMSN, the protoplanetary disk would be near 3300 earth masses. A simple accretion disk origin for this giant exoplanet found on a wide orbit from the parent star does not work.

 

[rod]

FYI, another report popped up about another giant planet found far from its parent star, previously not detected. Giant planets forming far away from their parent stars is challenging

Citizen scientists find young-Jupiter-like object missed by previous exoplanet searches, https://phys.org/news/2021-12-citizen-scientists-young-jupiter-like-previous-exoplanet.html

Reference paper, A Wide Planetary Mass Companion Discovered through the Citizen Science Project Backyard Worlds: Planet 9, https://iopscience.iop.org/article/10.3847/1538-4357/ac2499, 09-Dec-2021.

My observation. The NASA ADS Abstract, A Wide Planetary Mass Companion Discovered Through the Citizen Science Project Backyard Worlds: Planet 9, https://ui.adsabs.harvard.edu/abs/2021arXiv211204678F/abstract, December 2021. I note that 37 arcsecond resolution = 1662 au, indicates the distance is some 45 pc from Earth. The 22 page arXiv paper near the end (page 18), "Table 1. Measured Parameters" list the distance as 44.957 pc. The exoplanet listed as 15 Mjup = 4.7673E+03 earth masses or nearly 4800 earth masses. The host star is 1 solar mass so applying the MMSN, the protoplanetary disk would be near 3300 earth masses. A simple accretion disk origin for this giant exoplanet found on a wide orbit from the parent star does not work.