NASA New Earth-sister Kepler 452b announced by NASA

[lpetrich]

Wikipedia's contributors have added it: Kepler-452, Kepler-452b

Its star, Kepler-452, is very Sunlike.

Mass = 1.04 Msun, Radius = 1.1 Rsun, Lum = 1.2 Lsun, Temp = 5905 K, Age = 6 billion years, Distance = 1400 ly / 450 pc

Its planet, Kepler-452b, is the most Earthlike that the Kepler team has found.

Its size is 1.63 times the Earth's, the only observable physical feature of it so far. It orbits its star with a period of 385 days, meaning that it was likely seen transiting only 3 times during Kepler's 4-year primary-mission run. Its mean distance is about 1.04 times the Earth's. Scaling from the Earth's mean surface temperature of 15 C gives one of 21 C. So it may be close to having a Venus-like runaway greenhouse effect.

The Wikipedia article quotes a mass estimate of 5 times more than the Earth's, and I'll use it. That is presumably from it being all-rocky. If it had an ocean several thousand km deep, then it would be much less massive.

Surface gravity = 1.9 * Earth's or 18 m/s^2, orbital/escape velocity = 1.8 or (14 km/s, 20 km/s)

So while that planet can retain an atmosphere better than the Earth, it is more difficult to escape from. One will likely need an additional rocket stage to get into orbit.

 

[mfb]

So while that planet can retain an atmosphere better than the Earth, it is more difficult to escape from. One will likely need an additional rocket stage to get into orbit.

If intelligent life has developed there, they could have been at that stage a billion years ago. Enough time to find better techniques. The atmosphere is probably more dense, but it also falls of more quickly with height, even some non-rocket spacelaunch ideas we have today should work.

 

[Raman Choudhary]

Why is it that suddenly(why not earlier,is it because kepler is not fixed in space??) we found it as the telescope is there for many years??
How is the identification of the surface type(terrestrial,gaseous etc.) done from such a long distance??

 

[mfb]

Kepler needed to observe at least three transits to make sure it is a repeating pattern. With an orbital period of about one year, that takes two to three years of data-taking even in the best case. Add some telescope down-time and it can take four years. And that is just data-taking. There are many other effects that can mimic a planet signal (double stars, background stars, ...), so scientists have to look at the data in more detail. Often follow-up observations by other telescopes are necessary to rule out all other possible interpretations of the signal. All that takes a while.

How is the identification of the surface type(terrestrial,gaseous etc.) done from such a long distance??

The radius can be measured based on the amount of light the planet blocks. The orbital period also allows to determine the orbit. For Kepler 452b, everything else is educated speculation for now. It is too small to be a pure gas giant. It is possible to set upper limits on the mass based on radial velocity measurements, a direct measurement is not yet possible with the available telescopes. If other planets are found in the system, the mutual interaction between them can allow to measure the mass precisely.

 

[castor]

would be interesting to do ...

keeping in mind any tech advanced civilisation there would have to be well ahead of ours
We didn't have radio 300 yrs ago, let alone 1300 yrs ago any radio signal you received would have
been broadcast 1300 yrs ago Dave

PS ... unless of course, they advanced faster than we did

Not to mention, any intelligent life that may have developed over there wouldn't have much incentive to beam anything towards the Earth. Remember, the distance of 1400 ly works both ways. If any hypothetical life sent out signals 1400 years back, they would have done so following data they received from Earth, which is 1400 ly away from them. And the Earth was quite quiet in 785 BC.

Anyway, calling Kepler 452b Earth's sister or cousin or whatever is stupidity. Remember, they used to call Venus Earth's twin before the Venera probes crashed on its' surface.

 

[mfb]

And the Earth was quite quiet in 785 BC.

We still had a lot of oxygen in the atmosphere, which is very reactive and doesn't stay around for long unless nonequilibrium reactions produce it. In addition, the atmosphere has methane and various other chemicals that do not live long in an oxygen-rich atmosphere. Sure, we did not emit radio waves back then, but the atmosphere has been unusual for a very long time.

 

[rootone]

... they used to call Venus Earth's twin before the Venera probes crashed on its' surface.

Actually several of them soft landed and sent back images, though none lasted more than about an hour in the extreme temperature and pressure of Venus' atmosphere.
It wasn't at all what was expected, and the probes just were not built to take that kind of punishment.

 

[castor]

Don't take that literally. Crashed, soft landing, it doesn't really matter.

We really thought Venus might hold some form of life before the Venera probes dispelled that notion.

 

[Raman Choudhary]

How is this name assigned to the star and the planet

http://www.nasa.gov/keplerbriefing0723

As I type this, NASA is announcing discovery of a new planet Kepler 452b that is
- small and (probably) rocky like Earth
- orbits a G2 star
- is in the star's habitable zone
This is the first candidate that meets all three criteria. (Most Earth-twins so far discovered are around tiny red dwarfs, and orbit in a matter of days) It has a 385 day long year, almost exactly the same as Earth.

Kepler 452b is a slightly older sibling of Earth - it has lived in its habitable zone for 6 billion years. It's a little bigger, surface gravity is about 2x Earth, but it probably has a thick atmosphere as well as volcanism.

One implication of this discovery is that these are surely common. We only detect 1 in 50 planets because of alignment issues, so detection of one suggests another 50 out there we can't see with current equipment.

The one imperfection in this otherwise ideal Earth-sister is that it is more than 1300 light years away.

Sir,
How is this name assigned to the star(what's a G2??) and the planet??

 

[rootone]

Stars are classified by luminosity and size.
https://en.wikipedia.org/wiki/Stellar_classification
The star in this system is G class yellow star similar to our sun.

When a new star is registered it is the 'a' object for that system.
Second and subsequent objects found in the same system are denoted 'b' 'c' and so on.

 

[castor]

How is this name assigned to the star and the planet

Sir,
How is this name assigned to the star(what's a G2??) and the planet??

It's a part of the Hertzsprung-Russell classification or the Morgan-Keenan of stellar bodies, depending on their heat output from what I understood. Depending on their surface temperatures, stars are labelled O, B, A, F, G, K, and M in the decreasing order. Therefore, the hottest stars are O-type stars (which usually are extremely massive blue supergiants) to M stars (which are red stars). M stars are the most common type of star, and the O types are the rarest.

Our Sun is a G-type star. In addition to the alphabet G, the numeral 2 indicates the temperature of the star relative to the other classifications. That is, how close the star is to the next classification. The numerals range from 0 to 9, with 0 being the hottest and 9 being the coolest. Therefore, a G0 star which has nearly the same temperature as an F9 star.

Our Sun is a G2 type star, and so is Kepler-452.

The name Kepler-452d was assigned to the planet because it was the third planet found in the Kepler-452 system. The first object, which is the star itself, is Kepler-452. The first planet discovered will be named Kepler-452b, the second planet Kepler-452c, third planet Kepler-452d and so on.

 

[mfb]

The name Kepler-452d was assigned to the planet because it was the third planet found in the Kepler-452 system. The first object, which is the star itself, is Kepler-452. The first planet discovered will be named Kepler-452b, the second planet Kepler-452c, third planet Kepler-452d and so on.

The planet is b, not d, as there is only one planet found so far.

The name Kepler-452 for the star system does not have a deeper meaning. The star did not have a name before, Kepler found something interesting that makes a name useful, and it is the 452th system that got a name by the Kepler scientists.

 

[Monsterboy]

We still had a lot of oxygen in the atmosphere, which is very reactive and doesn't stay around for long unless nonequilibrium reactions produce it. In addition, the atmosphere has methane and various other chemicals that do not live long in an oxygen-rich atmosphere. Sure, we did not emit radio waves back then, but the atmosphere has been unusual for a very long time.

Is it possible to find the atmospheric composition of Kepler 452b by spectral analysis or something , with current technology ?

 

[Monsterboy]

it is the 452th system that got a name by the Kepler scientists.

You mean 452nd solar system ?

 

[philton]

I'd like to bet that 452-b is not the only planet of the planetary system, considering the scale of the 452 system. Anybody follows?

 

[Borg]

You mean 452nd solar system ?

Here's the Wiki article on naming conventions for Kepler objects of interest (KOIs). It goes into a little detail on where the names come from and how they are assigned.

 

[|Glitch|]

http://www.nasa.gov/keplerbriefing0723

As I type this, NASA is announcing discovery of a new planet Kepler 452b that is
- small and (probably) rocky like Earth
- orbits a G2 star
- is in the star's habitable zone
This is the first candidate that meets all three criteria. (Most Earth-twins so far discovered are around tiny red dwarfs, and orbit in a matter of days) It has a 385 day long year, almost exactly the same as Earth.

Kepler 452b is a slightly older sibling of Earth - it has lived in its habitable zone for 6 billion years. It's a little bigger, surface gravity is about 2x Earth, but it probably has a thick atmosphere as well as volcanism.

One implication of this discovery is that these are surely common. We only detect 1 in 50 planets because of alignment issues, so detection of one suggests another 50 out there we can't see with current equipment.

The one imperfection in this otherwise ideal Earth-sister is that it is more than 1300 light years away.

There is apparently some question as to whether Kepler-452b meets your first criteria.

Most 1.6 Earth-radius Planets are Not Rocky - Leslie A. Rogers 2015 ApJ 801 41. doi:10.1088/0004-637X/801/1/41 (arXiv free reprint)

Furthermore, based upon Weiss & Marcy (2014) the density of Kepler-452b should be 7.956 (+1.123, -0.976) g/cm³, giving the exoplanet a gravity of 4.237 (+0.598, -0.520), or 41.554 m/s².

 

[|Glitch|]

Other articles put the star at 1400 ly.

http://www.npr.org/sections/thetwo-...ope-introduces-earth-to-a-very-distant-cousin

The planet is about 1.6 times the size of earth. It would be interesting to know the mass.

http://www.nasa.gov/keplerbriefing0723
Technical paper - http://www.nasa.gov/sites/default/files/atoms/files/ms-r1b.pdf

Based upon Weiss & Marcy (2014) the mass can be estimated based upon the planet's radius.

Exoplanets with a radius in the range of 1.5 ≤ R_P/R_⊕ < 4 have an estimated mass of M_P/M_⊕ = 2.69(R_P/R_⊕)^0.93. Which would put Kepler-452b's estimated mass at 4.237 (+0.598, -0.520) M_⊕.

 

[DaveC426913]

There is apparently some question as to whether Kepler-452b meets your first criteria.

Yep. That's why I said probably. Scientists are saying 'a better than even chance it's rocky'.

 

[mfb]

Is it possible to find the atmospheric composition of Kepler 452b by spectral analysis or something , with current technology ?

I would be surprised, the planet is far away, small and next to a relatively bright star. On the other hand, I'm surprised by science frequently...
E-ELT is under construction, spectroscopy of exoplanet atmospheres is one of the main science goals.

 

[|Glitch|]

I would be surprised, the planet is far away, small and next to a relatively bright star. On the other hand, I'm surprised by science frequently...
E-ELT is under construction, spectroscopy of exoplanet atmospheres is one of the main science goals.

Kepler-452b has one advantage going for it - the exoplanet was discovered using the transit method. Which should make the spectroscopy of Kepler-452b much more likely. Exoplanet atmospheres would be extremely difficult to discern if they did not transit in front of their parent star. We would have to wait until the James Webb Space Telescope came on-line in late 2018.

 

[DaveC426913]

Kepler-452b has one advantage going for it - the exoplanet was discovered using the transit method.

True. Though that makes me wonder why they don't already know whether its rocky or gaseous. Surely the light curve would be markedly different for each.

 

[mfb]

True. Though that makes me wonder why they don't already know whether its rocky or gaseous. Surely the light curve would be markedly different for each.

Why?
The orbital speed is about 30 km/s, an atmosphere of ~50 km (with relevant density) would influence the light curve by less than a percent (1% of a 0.01%-effect!), and only alter the shape for about 2 seconds each. There is no way to see such a small and short effect with Kepler.

 

[Bandersnatch]

True. Though that makes me wonder why they don't already know whether its rocky or gaseous. Surely the light curve would be markedly different for each.

Head to:
http://www.planethunters.org/
where you can help classify light curves collected by the Kepler mission. The follow up observations are somewhat more detailed, and their data can be seen in the discovery papers listed on that site.
It should help appreciate what kind of data constitutes a transit and how much can you read out of it.

Here's an example for Kepler-289 d:

 

[DaveC426913]

Head to:
http://www.planethunters.org/
where you can help classify light curves collected by the Kepler mission. The follow up observations are somewhat more detailed, and their data can be seen in the discovery papers listed on that site.
It should help appreciate what kind of data constitutes a transit and how much can you read out of it.

Yeah, I've done a fair bit of planet hunting there.

 

[LeDragonian]

They might be broadcasting their own version of Star-Trek!

Maybe they have a less annoying Cpt. T. Kirk.

 

[Mad scientist]

Is there any similar telescope planned to replace it eventually?

The James Webb Space Telescope is due to be launched in 2018:

http://jwst.nasa.gov/about.html

 

[rootone]

Yes I knew of the JWST, but this seems to be more of a replacement for Hubble (with extended infrared sensitivity).
I'm not sure if it could be used for the same type of planet-finding work which Kepler is doing.

 

[mfb]

TESS is basically an improved Kepler telescope.

It can reveal interesting candidates for observations with JWST which has a much broader science mission (JWST cannot keep observing the same stars for years).

PLATO could be even better, but certainly later.

See also the "Exoplanet search projects" navigation bar at the end of the article for more missions.

 

[Mad scientist]

Yes I knew of the JWST, but this seems to be more of a replacement for Hubble (with extended infrared sensitivity).
I'm not sure if it could be used for the same type of planet-finding work which Kepler is doing.

One of its main objectives is to study the atmospheres of exoplanets and search for the building blocks of life.