Exoplanet, HD 137010 b and it's star, HD 137010

[Astronuc]

An article appeared recently about an earth-like planet, HD 137010 b, which is around an orange start, HD 137010. Of course, I wanted more information

HD 137010 b is an unconfirmed exoplanet detected around star HD 137010. More observations are needed to confirm its existence.
https://www.stellarcatalog.com/exoplanet.php?planetID=102153
Distance from the star: 0.88 AU
Orbit around star: 355 days
Temperature: 205 K | -68.15 °C
Estimated size ~ 1.06 earth diameter

Earth-like in the sense of size, but the environment is more like an icy planet.

Star HD 137010 - Orange star HD 137010 is located 146 light years away from the Sun. It is a single star of spectral class K3.5V, that has 73 % of solar mass. There is at least one exoplanet in this system.
https://www.stellarcatalog.com/stars/hd-137010
Location:
Right ascension: 15h 24m 21.513s
Declination: -19° 44' 25.649'' (equatorial region)
Parallax: 22.292
Sun distance: 146.309 ly | 44.9 pc
Basic characteristic
Mass: 72.6 % M Sun
Size: 71 % R Sun
Temperature: 4770 K | 0.83 T Sun. - what a difference 1000K can make
Age: 4.8 billions years | 1.04 Sun
Luminosity: 0.232 L Sun

https://science.nasa.gov/universe/exoplanets/discovery-alert-an-ice-cold-earth/

https://en.wikipedia.org/wiki/HD_137010_b

 

[sbrothy]

An article appeared recently about an earth-like planet, HD 137010 b, which is around an orange start, HD 137010. Of course, I wanted more information

HD 137010 b is an unconfirmed exoplanet detected around star HD 137010. More observations are needed to confirm its existence.
https://www.stellarcatalog.com/exoplanet.php?planetID=102153
Distance from the star: 0.88 AU
Orbit around star: 355 days
Temperature: 205 K | -68.15 °C
Estimated size ~ 1.06 earth diameter

Earth-like in the sense of size, but the environment is more like an icy planet.

Star HD 137010 - Orange star HD 137010 is located 146 light years away from the Sun. It is a single star of spectral class K3.5V, that has 73 % of solar mass. There is at least one exoplanet in this system.
https://www.stellarcatalog.com/stars/hd-137010
Location:
Right ascension: 15h 24m 21.513s
Declination: -19° 44' 25.649'' (equatorial region)
Parallax: 22.292
Sun distance: 146.309 ly | 44.9 pc
Basic characteristic
Mass: 72.6 % M Sun
Size: 71 % R Sun
Temperature: 4770 K | 0.83 T Sun. - what a difference 1000K can make
Age: 4.8 billions years | 1.04 Sun
Luminosity: 0.232 L Sun

https://science.nasa.gov/universe/exoplanets/discovery-alert-an-ice-cold-earth/

https://en.wikipedia.org/wiki/HD_137010_b

Intriguing, albeit hardly inviting!

 

[ioannisakousoulakos]

Good evening , very interesting . I dropped the data into my Model for predictions and the results are as it follows . Star mass ( HD 137010 ) = 0.7215 M☉ , planet mass (HD 137010b) = 1.19 M_Earth ( our prediction ) , orbital velocity = 26.97 km/s ( prediction matches observation by 99,99 % )

 

[sbrothy]

This link:

https://www.sciencealert.com/scientists-reveal-a-frozen-bizarro-earth-only-150-light-years-away

says 1.2 Earth mass, you 1,19. I guess not much practical difference, what would it mean for how high its gravity is? practically the same as Earth or a big difference?

 

[ioannisakousoulakos]

G x 1.19 = 11,6739 m/s2 , yes it's one not substantial difference that can be compatible with human life in the long term , if this is what you mean same as earth . Mars per example is a no no for extended stays

 

[sbrothy]

G x 1.19 = 11,6739 m/s2 , yes it's one not substantial difference that can be compatible with human life in the long term , if this is what you mean same as earth . Mars per example is a no no for extended stays

Oh yeah duh. That was a pretty inane question. I have no excuse. I\m not even inebtriated. I just had a movie running in the background.

 

[mjc123]

G x 1.19 = 11,6739 m/s2 , yes it's one not substantial difference that can be compatible with human life in the long term , if this is what you mean same as earth . Mars per example is a no no for extended stays

Remember to account for the different radius; g = GM/r².
So g x 1.19/1.06² = 10.39 m/s²

 

[sbrothy]

Remember to account for the different radius; g = GM/r².
So g x 1.19/1.06² = 10.39 m/s²

Ah thanks. So not completely inane. Just not thought through!

You saved a little of my honor there, didnt you? Im grateful. Its not much but Ill take it!

 

[ioannisakousoulakos]

Remember to account for the different radius; g = GM/r².
So g x 1.19/1.06² = 10.39 m/s²

This is right , I messed the Newtonian with my own formulas . My sovereign equation for surface gravity is:

α = K · Ξ · 𝒩 / (4πR²)

The radius squared is in the denominator. So the ratio to Earth is:

α_b / α_Earth = (M_b / M_Earth) / (R_b / R_Earth)²

= 1.19 / (1.06)²

= 1.19 / 1.1236

= 1.059

α_b = 1.059 × 9.81 = 10.39 m/s²

So the correct surface gravity is 10.39 m/s², not 11.67.

 

[Cerenkov]

My first question concerning this planet wouldn't be about the planet itself.

It would be about the host star.

It's listed as a K3.5V. But is it a flare star? Or, if it isn't, is it still much more active than our Sun.

Is there any data on that?

The way I see it is that if the host star is 'hostile' then that makes significant inroads into the possibility of its planets being 'life-friendly'.

I don't want to rain on anyone's parade here, but... what about HD137010 itself?

Cerenkov

 

[ioannisakousoulakos]

My first question concerning this planet wouldn't be about the planet itself.

It would be about the host star.

It's listed as a K3.5V. But is it a flare star? Or, if it isn't, is it still much more active than our Sun.

Is there any data on that?

The way I see it is that if the host star is 'hostile' then that makes significant inroads into the possibility of its planets being 'life-friendly'.

I don't want to rain on anyone's parade here, but... what about HD137010 itself?

Cerenkov

α_star / α_Sun = (M_star / M_Sun) · (R_Sun / R_star)²

= 0.726 / (0.707)²

= 0.726 / 0.4998 = 1.4524

α_star = 1.4524 × 274.0 = 397.96 m/s²

Observed (log g = 4.60): 10⁴·⁶⁰ cm/s² = 398.1 m/s²

Agreement: 99.96%

• Luminosity: Only 23.2% of the Sun's output.
• Temperature: About 4770 K, compared to the Sun's 5778 K.

Even though the planet orbits at a distance similar to Earth (0.88 AU), the star is just too faint. This results in an estimated surface temperature of around −68°C, which is colder than Mars. The search results do mention one theoretical possibility for warmth. If HD 137010 b has an atmosphere much denser and richer in carbon dioxide (CO₂) than Earth's, the greenhouse effect could potentially warm it enough for liquid water. But this is not a typical situation for planets on that kind of orbit .

EPILOGUE =
SO, NO. THE POSSIBILITIES OF LIFE EXISTENCE ON THE EXAMINED PLANET ARE MINIMAL TO NONE.

 

[Cerenkov]

Thanks for the information, ioannisakousoulakos.

But my bad for not making my point clearer.

I was interested to know if there's any data on the volatility of the host star in terms of flaring. We already know that M-class stars are prone to flaring and that over millions and billions of years this activity can seriously degrade or even strip the atmospheres of nearby planets. But are K-type stars prone to flaring too?

If so, then if HD137010 is known to flare powerfully this might render the whole topic of its suitability for life a moot point. Then it wouldn't matter that the planet is approximately Earth-sized or that it might possess a thick atmosphere that insulates it and raises its surface temperature. The host star might have already stripped or thinned its atmosphere so much as to make life impossible anyway.

However, I don't know a great deal about these things and I'm only going on what I've read in popular-level science articles. There's also the fact that the flaring M-class stars possess planets that orbit orbit much closer in that HD137010b. Which makes them extremely vulnerable to atmosphere-stripping.

Given that this is a K-type star and that planet b is much further out, my fears might be groundless. Hence my interest in the star's activity. It would be nice to know one way or another.

Thanks,

Cerenkov.