First rocky extra solar panet discovered

[kane007]

Astronomers have announced - http://spaceflightnow.com/news/n0506/13planet/ - they have found the 1st rocky - earth like - extra solar world, albeit over 7 times as massive as earth, twice our girth, and dam hot!<br /><br />Also at http://www.space.com/scienceastronomy/050613_super_earth.html<br />

 

[najab]

This is <b>BIG</b> news - literally!

 

[5stone10]

<font color="yellow">they have found the 1st rocky - earth like - extra solar world...</font><br /><br />...not orbiting a pulsar.

 

[emperor_of_localgroup]

Artist's conception? Dont get me wrong, if it's a real earthlike planet , i'd be one of the happiest. But the artist drew something that very much looks like a picture of the earth seen from space. Where is the actual photo? Have to wonder, are these real planets or paper publishing frenzy. <div class="Discussion_UserSignature"> <font size="2" color="#ff0000"><strong>Earth is Boring</strong></font> </div>

 

[absolutezero]

This is awesome! But yeah,lets see the photo!!!

 

[formulaterp]

I don't think there is an actual photo. The planet along with it's 2 Jupiter sized neighbors, were discovered by analyzing the gravitationally induced wobble of the star itself. A visible light photo may be difficult if not impossible to capture with current technology. I would guess the best bet to actually image this planet would be in the IR portion of the spectrum. Perhaps they will task Spitzer to take a look. Either way don't expect to see much more than a fuzzy blob. All the more reason to fund and complete JWST and TPF.

 

[kdavis007]

That is true.. It seems that we are finding more planets not using the Hubble Space Telescope.. Why are keeping this worthless thing again???

 

[formulaterp]

Please. Hubble is a telescope. Like telescopes any amateur can buy, it is suited for certain uses. No telescope can image absolutely everthing in the heavens. Over the past decade or so NASA has launched giant scopes which covered the visible light, IR, X-Ray and Gamma Ray portions of the spectrum. Hubble is our visible light eyes on the universe. Hubble is expensive to maintain certainly, but it arguably the most useful and succesful space science project ever undertaken. There are no current plans (nor funds) to replace it. Until there are, why WOULDN'T we keep that worthless thing. <br /><br />JWST and TPF would offer new windows on the universe, exciting ones at that. And I hope work continues on both. But are they better than the worthless Hubble? I would say no, if only because Hubble actually exists.

 

[kane007]

We don't have the technological infrastructure yet to image in the visible spectrum such an extra solar world. In fact as I understand it only one super Jupiter exo planet has been observed directly in this spectrum.<br /><br />I believe TPF, Darwin (ESA), and SAFIR observe in the infrared not visible (HST) wavelengths. <br /><br />We may have to wait for something akin to TAU before we can gaze upon strange new continents.

 

[igorsboss]

What would its escape velocity be?<br /><br />Assuming it cooled down to standard temperature, would it be possible to construct a rocket capable of achieving escape velocity from this world?

 

[formulaterp]

"What would its escape velocity be?"<br /><br />Given a mass of 7.5x the Earth and 2x the radius, escape velocity will be on the order of 21.6 km/s (compared to 11.2 km/s for Earth)<br /><br />Could you build a rocket to blast off the planet? Sure you could, won't be easy though. Why do you ask?<br /><br />

 

[najab]

><i>It seems that we are finding more planets not using the Hubble Space Telescope.</i><p>Largely because the 'wobble' method of finding extra-solar planets requires long integration times, a luxury we don't have with HST.</p>

 

[silylene old]

Well, I am not convinced, from the scanty and contradictory press releases we have seen, that this is a hot rocky planet with little or no atmosphere. Perhaps it could be a medium-sized gas-ball, another Neptune that has spiraled in close to its sun. (yes, I know Neptune is 17.5 earth masses, not 7.5 as is the new planet). Perhaps it could be an intermediate rocky-gas ball..... an earth-sized rocky/iron core surrounded by a super-thick dense hell-hole atmosphere (think a hybrid of Venus and Neptune).<br /><br />I'd really like to see some serious simulation work before we conclude that this new planet is definately a rocky ball. Sound like too much hand-waving to me at this stage.<br /><br />The space.com article is nicely self-contradictory on whether this planet could hold an atmosphere or not:<br /><i>Orbiting so close to its star, scientists speculate that the planet’s temperature is a toasty 400 to 750 degrees Fahrenheit (200 to 400 degrees Celsius). This is likely too hot for the planet to retain much gas, like Jupiter does. Therefore, the planet must be mostly solid. <br /><br />"The planet's mass could easily hold onto an atmosphere," said Gregory Laughlin from UC Santa Cruz. "It would still be considered a rocky planet, probably with an iron core and a silicon mantle. It could even have a dense steamy water layer.” <br /></i> <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>

 

[najab]

><i>The space.com article is nicely self-contradictory on whether this planet could hold an atmosphere or not...</i><p>No, that's not a contradiction. What they said is that it's too hot to be a gaseous planet (ie to be almost entirely gas like the gas giants in our Solar system), but that doesn't preclude that it may hold on to <i>some</i> atmosphere like the Earth (our atmosphere is less than 1% of the total mass of the planet).</p>

 

[silylene old]

I am still unconvinced that this new planet is not a mini-Neptune. I'd like to see this modeled. Too much conjecture at this point! <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>

 

[silylene old]

thanks, that's a good explanation and much better than the news reports. <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>

 

[robnissen]

You wrote: "If the pressure at the bottom of the atmosphere is twenty or thirty times as great as on Earth a water ocean is possible at 200 celsius; however the greenhouse effect would probably make the surface temperature even higher than that." <br /><br />But being a couple million miles from its star, this planet must be tidally locked. That being the case, the temperature on the dark side would be lower. But if this planet has a thick atmosphere, there should be heat flows from the sunlit side to the dark side. That being the case, even with a greenhouse effect, it seems likely that somewhere on this planet, there would be a very real likelihood of liquid water. <br /><br />Speaking of which, does anyone know if there is model somewhere, on what the heat flows would be on a tidally locked planet that contains a thick atmosphere?<br /><br /><br />

 

[thalion]

I agree with the press releases that this is probably a rocky planet, though like Eburacum I think it has a dense atmosphere. However, I don't think it's a smaller version of Neptune, with a vast gaseous envelope, for two reasons:<br /><br />1.) IIRC, this planet isn't quite massive enough to accrete a deep, jovian-like blanket of gas, something that I've heard happens around 9-10 Earth masses.<br /><br />2.) The planet--though very hot--is not quite hot enough, IIRC, for it to have lost most of its atmosphere to ablation from its parent star, making it a stripped-down gas giant.<br /><br />I think a major weakness of theorizing at this point is that I don't think much modeling has been done at all on how planets might form around red dwarf stars. So I would agree that more simulation and calculation must be done.

 

[teije]

Rocky or not, atmosphere or not,<br />if it is confirmed it will certainly be the lightest and probably be the smallest object found so far around another star. That in itself already makes it a breakthrough.<br />Go planethunters!<br /><img src="/images/icons/smile.gif" />

 

[dragon04]

"But being a couple million miles from its star, this planet must be tidally locked. That being the case, the temperature on the dark side would be lower."<br /><br />How cool is the "dark side" of Venus? While I understand that Venus does rotate, it's a very slow rotational rate (approximately 243 days).<br /><br />I'd guess that Venus could be used as a comparative model depending on how dense an atmosphere this newly discovered planet may have.<br /><br />"That being the case, even with a greenhouse effect, it seems likely that somewhere on this planet, there would be a very real likelihood of liquid water."<br /><br />http://www.extrasolar.net/planettour.asp?StarCatId=&PlanetId=296<br /><br />I don't think liquid water is going to exist at any atmospheric pressure at a mean temp of 626K.<br /><br />According to the above link, the habitable zone for Gliese 876 is almost 3x the distance of this planet's current orbit.<br /><br />Using the above link's data, this planet would be orbiting Sol at roughly 17.5 million miles for comparison.<br /><br /><br /><br /> <div class="Discussion_UserSignature"> <em>"2012.. Year of the Dragon!! Get on the Dragon Wagon!".</em> </div>

 

[robnissen]

"I don't think liquid water is going to exist at any atmospheric pressure at a mean temp of 626K."<br /><br />While I agree with that statement as far as it goes, that doesn't really address my question. First, looking at the link you provided, the mean temperature appears to be the mean based on the planet's orbit, i.e., the average temp of the planet between when it is closest to its star and furthest. But it seems to me that any value calculated must be the average high temp., that is the average temp on the star lit side, NOT the average temp of the planet. How could they possibly guess what the temp on the dark side of the planet was, without knowing a lot more about the planet's atmosphere. That being the case, just because the average temp. on the star lit side is 626k, all we could know for sure, is that the average temp on the dark side would be substantially less. And, I don't think its unreasonble to believe that the side that is always dark could easily be 200K less than the sun lit side. At 426K, there could certainly be liquid water at the atmospheric pressures that seem likely to exist on that planet.<br /><br />

 

[gavino]

This discovery proves that are planet finding tools are getting much better. <div class="Discussion_UserSignature"> <p><span style="font-style:italic" class="Apple-style-span">gavinovz</span></p><p> </p> </div>

 

[dragon04]

Okay Rob. You got me interested in the substance of your question.<br /><br />So I did a little surfing. I found this very interesting link.<br /><br />http://www.treitel.org/Richard/rass/tidelock01.txt <div class="Discussion_UserSignature"> <em>"2012.. Year of the Dragon!! Get on the Dragon Wagon!".</em> </div>

 

[robnissen]

Thx for the link. That was EXACTLY what I was looking for. From that link, it appears that this new planet might be even more interesting than first appears.