Thread by @EmDwarf

We've got a very exciting announcement today!

✨ A Whole New World ✨

Introducing, TOI-700 e! TESS’s 2nd Earth-sized planet in the habitable zone of its host star and sibling to TOI-700 d (the first Earth-sized planet in the habitable zone from TESS)

Here is the press release talking about this new planet in the TOI-700 system!
nasa.gov/feature/nasa-s…

TOI-700 e joins planets b, c, and d that we announced back in 2020. For a full explainer of the initial system discovery, please check out this thread!

https://twitter.com/EmDwarf/status/1214370072375906305?s=20&t=1xikV3zHc1EmDZdK76FsIg

(I’ll leave the background science to that thread rather than reiterate it all here)

This new world, TOI-700 e is a small (95% the radius of Earth) planet, that is likely rocky (like the inner Solar System planets)

We found it using data from @NASA_TESS, which re-observed this star in its 3rd year of operations.

@NASA_TESS Because of the timing of these transits and the small size of the planet, we needed this additional year of data in order to detect TOI-700 e. Here you can see the planet signal build up over time as TESS observed more and more transits:

@NASA_TESS TOI-700 e has an orbital period of 27.8 days, which puts it within the optimistic habitable zone of TOI-700. This is the slightly expanded version of the conservative habitable zone, which accounts for the fact that we know Venus and Mars once had liquid water on their surfaces.

Because we found TOI-700 e after planets b, c, and d, it gets the moniker ‘TOI-700 e’ even though it breaks alphabetical order. So from inner to outer, the planets in this system go: b, c, e, d!

TOI-700 now hosts *TWO* habitable zone planets, which lets us study how different planetary properties affect their potential habitability.

We think this planet is likely tidally locked, meaning one side of the planet always faces the star and the other is in perpetual night.

Let me know if you have any questions and peep the Easter egg of TOI-700 d hanging out in the distance behind planet e in this animation : )

https://twitter.com/NASAExoplanets/status/1612885376019927056?s=20&t=GKwxtch9JG8s14u_ICI4XQ

Special thanks to all of the coauthors who contributed to this work! including but not limited to @amvanderburg @Astro_JRod @benhord @mrtommyb @elsisrad @ExoCytherean @twitspek

(the conference wifi, twitter search, and my brain are all struggling right now)

Bonus content! As far as I know, TOI-700 is the only exoplanet system with a custom emoji! Here’s a graphic you can add to slack, and track me down at #AAS241 if you want a TOI-700 emoji sticker!

Read the full TOI-700 e discovery paper here!

arxiv.org/abs/2301.03617