• Visit 'Mars' in Space.com's new 'Space Traveler' mini-documentary - Watch here! 🚀

Discovery of other planets with liquid water

Status
Not open for further replies.
D

dph2112

Guest
<p style="margin:0in0in0pt;text-align:justify" class="MsoNormal"><font face="Times New Roman" size="3">How are astronomers seeking planets with liquid water? The reason I ask is because as I understand it, our solar system is unique.&nbsp;Most planets in our solar system have fairly circular orbits around the sun. (As opposed to <u>very</u> elliptical orbits) Obviously, planets with very elliptical orbits probably do not remain temperate enough to either keep water between 0-100C. That being said, I would imagine planets with very large ellipses would have trouble keeping water (in any form) on the planet surface all together. </font></p><font face="Times New Roman" size="3">&nbsp;</font> <p style="margin:0in0in0pt;text-align:justify" class="MsoNormal"><font size="3"><font face="Times New Roman"><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span>So my question becomes, would a good starting point for discovery of water on other planets be to first identify planets with a more circular orbit around its star? (or even moons of other planets for water in any form) Thanks.</font></font></p><font face="Times New Roman" size="3">&nbsp;</font> <p style="margin:0in0in0pt;text-align:justify" class="MsoNormal"><font face="Times New Roman" size="3">(apologize if that is what astronomers are doing already)</font></p>
 
M

MeteorWayne

Guest
<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>How are astronomers seeking planets with liquid water? The reason I ask is because as I understand it, our solar system is unique.&nbsp;Most planets in our solar system have fairly circular orbits around the sun. (As opposed to very elliptical orbits) Obviously, planets with very elliptical orbits probably do not remain temperate enough to either keep water between 0-100C. That being said, I would imagine planets with very large ellipses would have trouble keeping water (in any form) on the planet surface all together. &nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; So my question becomes, would a good starting point for discovery of water on other planets be to first identify planets with a more circular orbit around its star? (or even moons of other planets for water in any form) Thanks.&nbsp; (apologize if that is what astronomers are doing already) <br />Posted by dph2112</DIV><br /><br />Welcome to Space.com!</p><p>&nbsp;Yes, a starting point is to find circular orbits at the right distance from the star for water to exist in liquid form. For our solar system that's about from the orbits from Venus to Mars.</p><p>However, Venus lost it's water due to a runaway greenhouse effect, and almost all (or all) water on Mars is frozen because Mars wasn't big enough to hang on to it's atmosphere so has no greenhouse effect.</p><p>BTW, circular orbits may not be rare, we are still developing the technology to discover them.</p><p>The easiest exoplanets to discover are those with highly elliptical obits of massive planets. SO those are the ones we've discovered first. BY 10 years from now, I suspect the types of stellar systems we know about will be more balanced.</p> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>
 
D

dph2112

Guest
<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Welcome to Space.com!&nbsp;Yes, a starting point is to find circular orbits at the right distance from the star for water to exist in liquid form. For our solar system that's about from the orbits from Venus to Mars.However, Venus lost it's water due to a runaway greenhouse effect, and almost all (or all) water on Mars is frozen because Mars wasn't big enough to hang on to it's atmosphere so has no greenhouse effect.BTW, circular orbits may not be rare, we are still developing the technology to discover them.The easiest exoplanets to discover are those with highly elliptical obits of massive planets. SO those are the ones we've discovered first. BY 10 years from now, I suspect the types of stellar systems we know about will be more balanced. <br />Posted by MeteorWayne</DIV><br /></p><p>&nbsp;</p><p style="margin:0in0in0pt" class="MsoNormal"><font face="Times New Roman" size="3">Thanks MeteorWayne! </font></p><p>&nbsp;</p>
 
D

doubletruncation

Guest
<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>How are astronomers seeking planets with liquid water? The reason I ask is because as I understand it, our solar system is unique.&nbsp;Most planets in our solar system have fairly circular orbits around the sun. (As opposed to very elliptical orbits) Obviously, planets with very elliptical orbits probably do not remain temperate enough to either keep water between 0-100C. That being said, I would imagine planets with very large ellipses would have trouble keeping water (in any form) on the planet surface all together. &nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; So my question becomes, would a good starting point for discovery of water on other planets be to first identify planets with a more circular orbit around its star? (or even moons of other planets for water in any form) Thanks.&nbsp; (apologize if that is what astronomers are doing already) <br /> Posted by dph2112</DIV></p><p>Just a note about the eccentricity of the planets. While it's true that there may be an eccentricity bias in the radial velocity surveys, most of the major searches for planets are more or less complete regardless of eccentricity for planets larger than ~saturn within an AU of their star (i.e. they've found all of the ~saturn or larger planets orbiting within an AU of the ~1000 or so stars that they've been monitoring for the last ~15 years). The distribution of eccentricity is interestingly quite broad (there are certainly some very low eccentricity planets, but there are also many high eccentricity ones) - an interesting place to see what the distribution looks like is at: http://exoplanet.eu/catalog-RV.php?mdAff=diag#tc set the x-axis to Planet semi-major axis or orbital period, and the y-axis to eccentricity, then choose a log-scale for the x-axis and a linear scale for the y-axis and click ok. The eccentricity varies from 0 (a perfect circle) to 1 (a parabola), the closer to 1 the more elliptical the orbit is. For reference Jupiter's eccentricity is ~0.05 and its semi-major axis is 5.2 AU (which corresponds to roughly the maximum distance that exo-planets have been found from their stars via RV), while Saturn has an eccentricity of ~0.05 and a semi-major axis of 9.5 AU. </p><p>I think it's a little premature though to make guesses as to the habitability of eccentric planets - particularly since we don't know the obliquity of these planets. After all, if you get more than ~45 degrees from the Earth's equator you find yourself in a location where water is frozen for a good chunk of the year and these places are still habitable, a good deal of life shuts down for half the year at these latitudes but comes back in full glory when it thaws out. I would guess that it'd be tougher for life if the planet was too hot during periastron but just right during apoastron than if the planet is just right at periastron but too cold at apoastron. </p> <div class="Discussion_UserSignature"> </div>
 
N

neilsox

Guest
Are we finding Saturn mass planets more than 400 million miles from even class M stars in approximately circular orbits by any method?&nbsp;&nbsp;&nbsp; Neil
 
Status
Not open for further replies.

ASK THE COMMUNITY

Latest posts