TOI-2155 b Brown Dwarf Or Red Dwarf?

Jul 21, 2026 9:51 AM

Oktay74tn

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TOI-2155 b Brown Dwarf Or Red Dwarf?
Oktay Yürük aka Oktay74tn, science and tech content
https://imgur.com/user/Oktay74tn

This is an artist's impression of a brown dwarf in a close orbit around a bright star. TOI-2155 b (TOI TESS Object of Interest) is a substellar object at a distance of 1,350 light years from Earth. It orbits the massive F-type star TOI-2155 with 1.3 solar masses.

The TESS (Transiting Exoplanet Survey Satellite) target pixel file illustrates the flux distribution within the sector. The red outlines mark the photometric aperture from SPOC ?, the data supplied by the Science Processing Operations Center. The massive star with a surface temperature of 6,085 Kelvin contributes 97% of the total flux.

This diagram shows the TESS data from the transit of TOI-2155 b as gray points. The red curve is from a model. Binned data is shown in blue. The companion has an orbital period of 3.7 days.

The brown dwarf desert describes the scarcity of brown dwarfs on short orbital periods. TOI-2155 b is in the lower part of the brown dwarf desert. Its origin is currently being researched. For a sun-like star, the desert extends up to 5 Astronomical Units (Sun-Jupiter distance, 1 AU is the Earth-Sun distance of 150 million kilometers or 93 million miles).

This is a mass–radius diagram for known transiting brown dwarfs in blue and low-mass stars in orange. TOI-2155 b with 80.6 Jupiter masses is highlighted in red. It is in the transition zone between brown dwarfs and red dwarf stars. The hydrogen burning minimum mass, the critical mass required to sustain nuclear fusion of hydrogen-1, is at 66 to 82 Jupiter masses. It depends on several factors, such as metallicity (abundance of chemical elements other than hydrogen and helium) and cloud properties.

(The gray zone on the left of the diagram is the deuterium burning limit that separates brown dwarfs from gas giants.)

TOI-2155 b is a very massive brown dwarf or a low-mass hydrogen-burning star. It has a high density of 109 grams per cubic centimeter. Its core is probably dominated by electron degeneracy pressure. The object has cooled and contracted significantly over its lifetime of 3.2 billion years.
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TOI-2155 b: A Massive Brown Dwarf or a Very Low-mass Star?
Md Redyan Ahmed, Tansu Daylan, Theron W. Carmichael, et al.
https://iopscience.iop.org/article/10.3847/1538-3881/ae7370

What makes a star a star? A strange 'in‑between' celestial object is testing astronomers' boundaries
by Md Redyan Ahmed, The Conversation, edited by Gaby Clark, reviewed by Robert Egan
https://phys.org/news/2026-07-star-strange-inbetween-celestial-astronomers.html

Wikipedia articles
https://en.wikipedia.org/wiki/Brown_dwarf
https://en.wikipedia.org/wiki/Brown-dwarf_desert
https://en.wikipedia.org/wiki/Red_dwarf
https://en.wikipedia.org/wiki/F-type_main-sequence_star
https://en.wikipedia.org/wiki/Transiting_Exoplanet_Survey_Satellite
https://en.wikipedia.org/wiki/Electron_degeneracy_pressure
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Check out https://imgur.com/user/Oktay74tn for many more astronomy and technology videos.

😊👍

1 week ago | Likes 1 Dislikes 0

When you're a super planet. But people were expecting more and say you're barely a star. This hurts the planet's feelings.

1 week ago | Likes 1 Dislikes 0

Why the obsession with color? Can't astronomers move past that?

1 week ago | Likes 1 Dislikes 0

Brown Dwarfs are planets that almost became a star, red dwarfs are stars that just crossed the line from been just a planet ...

1 week ago | Likes 1 Dislikes 0

The way to tell is if it cold outside and if there is no kind of atmosphere. Are you all alone?

1 week ago | Likes 4 Dislikes 0

More-or-less.

1 week ago | Likes 2 Dislikes 0

Massive dwarf? Is that like jumbo shrimp, or Mobil Station?

1 week ago | Likes 2 Dislikes 0

It's cold outside, there's no kind of atmosphere

1 week ago | Likes 2 Dislikes 0

They doesn't look like a spaceship so it must be a brown Dwarf

1 week ago | Likes 5 Dislikes 1

1 week ago | Likes 1 Dislikes 0

Pepperoni star

1 week ago | Likes 3 Dislikes 0

1,350 light years ≈ 7936000000000 miles

1 week ago | Likes 2 Dislikes 1

6,085 Kelvin ≈ -267.06 ° Celsius or -448.72 ° Fahrenheit

1 week ago | Likes 2 Dislikes 2

109 grams ≈ .01716 stone or 3 7/8 ounces

1 week ago | Likes 1 Dislikes 0

1 week ago | Likes 20 Dislikes 0

In the beginning, God created the heavens and the earth and TOI-2155b

1 week ago | Likes 4 Dislikes 0

v

1 week ago | Likes 6 Dislikes 0

I love to bits what a nerd he is.

1 week ago | Likes 3 Dislikes 0

I think they prefer the term small people nowadays...

1 week ago | Likes 4 Dislikes 0

There will be more dwarf videos, e.g. dwarf planets, white dwarfs or dwarf galaxies :) .

1 week ago | Likes 2 Dislikes 0

I prefer the Tolkien way, Dwarves

1 week ago | Likes 1 Dislikes 0