Citizen scientists discover 2 gas giants around a distant sun-like star

rod

Oct 22, 2019
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Here is another report on this interesting exoplanet find. https://phys.org/news/2021-06-citizen-scientists-gaseous-planets-bright.html

My observation. Using 12 earth mass and 3.41 earth radii, b has mean density ~ 1.7 g cm^-3. Planets b and c masses and sizes with short orbital periods, our solar system has no planets like these. This is an important statement in the phys.org report. "Studying them together, both of them at the same time, is really interesting to constrain theories of how planets both form and evolve over time," said Nora Eisner, a doctoral student in astrophysics at the University of Oxford in the United Kingdom and lead author of the study."

HD 152843 is a star with two exoplanets (multiple exoplanet system) that is very different than our solar system configuration. The space.com report stated, "The star has a mass similar to that of the sun but is nearly 1.5 times bigger and slightly brighter, according to a NASA statement."

The host star is closer to 1.15 solar masses as reported at these sites.


 
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Yes, and using the canonical dust mass ratio to stellar mass (10^-4) (https://ui.adsabs.harvard.edu/abs/2015A&A...579A..82R/abstract),...
Isn't that just CO dust ratio? I think the typical overall dust ratio for a disk is something like 10^-3, IIRC.

...we could have 38.29 earth masses with total dust and gas disk mass 3829 earth masses, when the star is a proto-star evolving according to models.
This is interesting. How did you get these figures?
 
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rod

Oct 22, 2019
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Helio, ref your question in post #5. The puzzle of protoplanetary disk masses, https://ui.adsabs.harvard.edu/abs/2019asrc.confE..19M/abstract, December 2019.

My observation. Reference link, https://zenodo.org/record/3585204#.YMbQzfKSmUk, 19-Dec-2019, 31 page report. Page 2 shows 1% for dust mass, 99% for gas mass. Page 15 graph shows CO gas mass relative to Msun, 10^-5 to 10^-1 Msun mass. This is 3.329 earth mass to 33294 earth masses, a large gas mass range in the disks. Most of the data points are 10^-5 to 10^-3 Msun, 3.329 earth masses to 332.94 earth masses. Page 27 shows disk masses clustering around 10^-4 Msun, 33.294 earth masses. Page 28 shows some data points clustering around 10^-2 Msun, 3329.4 earth masses. TW Hya is referenced too. MS BING search reports TW Hydrae is 196 light-years away and 5 to 10 million years old. The abstract shows ALMA is finding CO gas masses in the disks often < 318 earth masses or smaller than Jupiter mass.

There are many reports now available on ALMA and disk masses. Example, Protoplanetary disk masses in NGC 2024: Evidence for two populations, https://ui.adsabs.harvard.edu/abs/2020arXiv200413551V/abstract, April 2020.

From the report attached, "Table 1. Continuum fluxes and masses for the detected disks." The disk masses are listed ranging from 2.5 earth masses to 1055 earth masses shown. 1055 earth masses is 3.17E-3 solar mass. "5. Conclusions In this article, we presented observations of a large field towards the center of NGC 2024, containing 179 protoplanetary disks, as well as several YSOs at earlier stages of evolution. The purpose of these observations was to characterize the disk masses in a young, massive star-forming region, and to use these masses to study how disk evolution is affected by the strong radiation fields and high stellar densities in such environments by comparing NGC 2024 to other regions. This comparison depends sensitively on our knowledge of the stellar populations of NGC 2024. By comparing CO velocity measurements with multi-wavelength surveys of YSOs and stellar ages, we can interpret the disk masses of the distinct populations in our field in a coherent way. This approach allows us to locate the Class II objects of NGC 2024 in the interstellar environment in much greater detail. In the future, a Guaranteed Time Observations program on the James Webb Space Telescope towards this region (ID 1190, PI: M. Meyer) will allow the properties of the stellar and substellar populations in this region to be constrained in greater detail, and to confirm the results presented here."

My note. NGC 2024 is the Flame Nebula in Orion, I have viewed this with my telescopes, https://en.wikipedia.org/wiki/Flame_Nebula
 
Page 2 shows 1% for dust mass, 99% for gas mass. Page 15 graph shows CO gas mass relative to Msun, 10^-5 to 10^-1 Msun mass. This is 3.329 earth mass to 33294 earth masses, a large gas mass range in the disks. Most of the data points are 10^-5 to 10^-3 Msun, 3.329 earth masses to 332.94 earth masses.
Ok, I see where that comes from. Thanks. [The Sun is ~ 330,000x the mass of Earth so a 1% dust ratio for the Sun would be 3300 earth-masses. ]

CO is the main tracer in astronomy. Hydrogen soon become molecular (H2) once it cools. But H2 doesn't almost no EM, so CO is used as a proxy. [The outer region of GMCs have a lot of atomic H, which does emit EM, so it is the interior of clouds that is difficult.]

But a disk is about 100x the mass of the Sun, IIRC. So there is some sort of potential for a lot more planetary masses, so things like supersonic flows or nearby gravity interactions may have contributed to forming those massive planets. Just guessing.

There are many reports now available on ALMA and disk masses. Example, Protoplanetary disk masses in NGC 2024: Evidence for two populations, https://ui.adsabs.harvard.edu/abs/2020arXiv200413551V/abstract, April 2020.
Yes, this seems to demonstrate a lot of regional variation in dynamics. They note on (pg 11) "If NGC 2024 as a whole is like the ONC, we might not expect a strong dependence on Mdisk with stellar mass, or none at all."
 
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