Super-Earth planet zips through the habitable zone of red dwarf star

[Admin]

Low mass and dim red dwarf stars account for 75% of stars in the Milky Way and astronomers are attempting to discover planets that orbit them.

Super-Earth planet zips through the habitable zone of red dwarf star : Read more

 

[rod]

Reference paper, A super-Earth orbiting near the inner edge of the habitable zone around the M4.5 dwarf Ross 508, https://academic.oup.com/pasj/advance-article/doi/10.1093/pasj/psac044/6623879?login=false, 30-June-2022. “Abstract We report the near-infrared radial velocity (RV) discovery of a super-Earth planet on a 10.77 d orbit around the M4.5 dwarf Ross 508 (Jmag = 9.1). Using precision RVs from the Subaru Telescope IRD (InfraRed Doppler) instrument, we derive a semi-amplitude of 3.92 +0.60/−0.58 ms^−1⁠, corresponding to a planet with a minimum mass m sini=4.00 +0.53/−0.55M⊕⁠..."

My observation. Using properties in the paper I calculated P = 1.0761E+01 or 10.761 day with e = 0. The abstract shows period is a "super-Earth planet on a 10.77 d orbit." Host star mass = 0.1774 Msun, exoplanet mass = 4.0045E+00 earth masses or 1.26E-2 Mjup. In 1 Gyr period, Ross 508 b could complete 3.3941E+10 or more than 33 billion revolutions around Ross 508 host star. The paper provides a system age spread of 1 to 10 Gyr - "We found no stellar companions at a separation wider than ∼0′′.1 from the central star. At separations exterior to 0′′.25 (rproj ∼ 2.8 au), the comparison of the contrast limits with the Baraffe et al. (2003) evolutionary models enables us to rule out companions that are more massive than 35 MJ or 70 MJ for an assumed system age of 1 Gyr or 10 Gyr, respectively."

I calculate mean density 5.3678 g cm^-3 for Ross 508 b using 4 earth mass and radius 1.6 earth radii.

 

[rod]

Details for Ross 508 b can be found at these sites.

The Extrasolar Planet Encyclopaedia — Ross 508 b (exoplanet.eu)

Ross 508 | NASA Exoplanet Archive (caltech.edu)

Using the exoplanet.eu site, I found another 86 exoplanets listed with masses 3 to 5 earth mass range. Host star masses range 0.06 Msun to 1.24 Msun. Orbital periods range 0.35 day to 98 days.