Star may have drawn scorching 'hell planet' into super-close orbit

[Admin]

The super-Earth exoplanet Janssen is so close to its star, a year is only 18 hours long.

Star may have drawn scorching 'hell planet' into super-close orbit : Read more

 

[rod]

Some other reports are out on this exoplanet now too.

How the 'hell planet' got so hot: New measurements reveal the orbital path of planet 55 Cnc e, https://phys.org/news/2022-12-hell-planet-hot-reveal-orbital.html

My note. This is a five-exoplanet system where the planets do not orbit around the host star in a flat plane. 55 Cnc e seems to do this, the other four are exceptions. Planet migration scenarios are used to explain the present orbit of 55 Cnc e.

ref - Measured spin–orbit alignment of ultra-short-period super-Earth 55 Cancri e, https://www.nature.com/articles/s41550-022-01837-2, 08-Dec-2022. “Abstract A planet’s orbital alignment places important constraints on how a planet formed and consequently evolved. The dominant formation pathway of ultra-short-period planets (P < 1 day) is particularly mysterious as such planets most likely formed further out, and it is not well understood what drove their migration inwards to their current positions..."

My note. "The spin–orbit alignment of 55 Cnc e favours dynamically gentle migration theories for ultra-short-period planets, namely tidal dissipation through low-eccentricity planet–planet interactions and/or planetary obliquity tides." My note, gentle migration theories. 55 Cnc e is documented at http://exoplanet.eu/catalog/55_cnc_e/

This is a five-exoplanet system. Using properties at exoplanet.eu for 55 Cnc e I calculate P = 6.9550E-01 day or 0.6955 day. The published value = 0.7365478 day. In 1 Gyr, 5.2516E+11 revolutions could be completed or more than 525 billion revolutions. The host star is said to be 10.2 Gyr old. More than 5 trillion revolutions now. Apparently, some type of gentle migration scenario is required to explain this exoplanet and five planet system.

Observing trillions of revolutions around the host star - looks difficult

 

[rod]

Exoplanet studies now are very interesting. Here is a new report on exoplanet masses and densities using 10^6 number in simulations. Efforts to quantify mass, density, and radius, exoplanets with radii 2 or less earth radii.

The Nominal Range of Rocky Planet Masses, Radii, Surface Gravities and Bulk Densities, https://arxiv.org/abs/2212.03934

My notes. From the 41-page PDF report. “1. INTRODUCTION The compositions of small (R <= 2Rearth) exoplanets provide considerable information about their formation (e.g., Unterborn et al. 2018a; Adibekyan et al. 2021), interior dynamics (Ballmer et al. 2017; Spaargaren et al. 2020), and potential habitability (e.g., Unterborn et al. 2022). Attempts to quantify the composition of small exoplanets has been ongoing for over a decade, by attempting to match a planet's measured density to those predicted by mass-radius models (e.g., Valencia et al. 2006; Seager et al. 2007; Valencia et al. 2007a,b; Zeng & Seager 2008; Dorn et al. 2015; Unterborn et al. 2016, 2018a; Huang et al. 2022). Recent work has used mass-radius modeling to identify high-density super-Mercuries (e.g., Bonomo et al. 2019) as well as small planets that contain significant surface water (e.g., Unterborn et al. 2014) or thick atmosphere (e.g, Brinkman et al. 2022), which lower their bulk densities considerably, making them water-worlds and mini-Neptunes, respectively.”

"Table 1. Sample of planets with uncertainties less than 30% in both mass and radius with the highest and lowest likelihood of being in NRPZ"

"Table 2. Sample of well-characterized exoplanets with available host-star abundances. Host star elemental ratios are expressed as molar ratios derived using the solar abundances of Lodders et al. (2009). All masses and radii taken from the NASA Exoplanet Archive (Akeson et al. (2013), 10.26133/NEA1) and stellar abundance data are from the Hypatia Catalog. The classifications in the last column are illustrated in Figure 21, where SM = Super-Mercury, and IHS = indistinguishable from host star. CMF values correspond to the median values and 1sigma confidence intervals"

Another note I make, presently 133 exoplanets have atmospheres studied and listed, http://research.iac.es/proyecto/exoatmospheres/index.php This is another critical parameter when thinking about if any exoplanets are earthlike.

The NASA exoplanet archive site presently shows 1474 exoplanets with radius 2 or less earth radii.
NASA Exoplanet Archive (caltech.edu)

The exoplanet.eu site shows 1404, The Extrasolar Planets Encyclopaedia (exoplanet.eu)

Exoplanet studies like this raise questions about are there indeed, habitable earthlike planets out there? Knowing and confirming specific properties of exoplanets is required to answer. Astrobiology at some point, must show biological life exists, somewhere other than here on Earth and abiogenesis doctrine for the origin of life on Earth needs this too.