This release states that Fomalhaut b is 'one billion times fainter' than it's star.
http://hubblesite.org/newscenter/archive/r...s/2008/39/full/
That amounts to a difference of about 22 magnitudes, making the magnitude of the observed object around 23. If my figures are correct that's over a hundred times brighter than one would expect a 'naked' planet to appear by reflected light. That would mean that it is the inferred proto-galilean disc around the planet which has been directly imaged, making this an indirect observation of the planet itself. Can anybody clarify this issue - or spot the howling blunder in my calculations?
Of course I don't seek to detract in any way from the magnificent achievement that this observation represents.
Full Version: "major" extrasolar planet discovery by Hubble
Aah! Thanks a million Tman - we posted simultaneously there. I couldn't find the full article myself. (EDIT - of course I could have just followed the links from Stu's post (!) ) So it seems my back-of-the-envelope was not too far off. In that case one must question the appropriateness of the press release headline "Hubble Directly Observes Planet . . . ".
Several papers are up on arXiv:
Optical Images of an Exosolar Planet 25 Light Years from Earth
Paul Kalas, James R. Graham, Eugene Chiang, Michael P. Fitzgerald, Mark Clampin, Edwin S. Kite, Karl Stapelfeldt, Christian Marois, John Krist
Fomalhaut is a bright star 7.7 parsecs (25 light years) from Earth that harbors a belt of cold dust with a structure consistent with gravitational sculpting by an orbiting planet. Here, we present optical observations of an exoplanet candidate, Fomalhaut b. In the plane of the belt, Fomalhaut b lies approximately 119 astronomical units (AU) from the star, and within 18 AU of the dust belt. We detect counterclockwise orbital motion using Hubble Space Telescope observations separated by 1.73 years. Dynamical models of the interaction between the planet and the belt indicate that the planet's mass is at most three times that of Jupiter for the belt to avoid gravitational disruption. The flux detected at 800 nm is also consistent with that of a planet with mass no greater than a few times that of Jupiter. The brightness at 600 nm and the lack of detection at longer wavelengths suggest that the detected flux may include starlight reflected off a circumplanetary disk, with dimension comparable to the orbits of the Galilean satellites. We also observed variability of unknown origin at 600 nm.
Fomalhaut's Debris Disk and Planet: Constraining the Mass of Fomalhaut b From Disk Morphology
E. Chiang, E. Kite, P. Kalas, J. R. Graham, M. Clampin
Following the optical imaging of the exoplanet candidate Fomalhaut b (Fom B ), we present a numerical model of how Fomalhaut's debris disk is gravitationally shaped by a single interior planet. The model is simple, adaptable to other debris disks, and can be extended to accommodate multiple planets. We find that to not disrupt the belt, Fom b must have a mass < 3 Jupiter masses. Previous mass constraints based on disk morphology rely on several oversimplifications. We explain why our constraint is more reliable. It is based on a global model of the disk that is not restricted to the planet's chaotic zone boundary. Moreover, we screen disk parent bodies for dynamical stability over the system age of 100 Myr, and model them separately from their dust grain progeny; the latter's orbits are strongly affected by radiation pressure and their lifetimes are limited to 0.1 Myr by destructive grain-grain collisions. The single planet model predicts that planet and disk orbits be apsidally aligned. Preliminary analysis of Fom b's space velocity does not bear this out. The disagreement might be resolved by having additional perturbers in the Fomalhaut system, for which there is independent evidence from the star's anomalous Hipparcos acceleration. Our upper mass limit of 3 Jupiter masses for Fom b is not affected by these considerations. The belt contains at least 3 Earth masses of solids that are grinding down to dust. Such a large mass in solids is consistent with Fom b having formed in situ.
From the first paper:
Bill
Optical Images of an Exosolar Planet 25 Light Years from Earth
Paul Kalas, James R. Graham, Eugene Chiang, Michael P. Fitzgerald, Mark Clampin, Edwin S. Kite, Karl Stapelfeldt, Christian Marois, John Krist
Fomalhaut is a bright star 7.7 parsecs (25 light years) from Earth that harbors a belt of cold dust with a structure consistent with gravitational sculpting by an orbiting planet. Here, we present optical observations of an exoplanet candidate, Fomalhaut b. In the plane of the belt, Fomalhaut b lies approximately 119 astronomical units (AU) from the star, and within 18 AU of the dust belt. We detect counterclockwise orbital motion using Hubble Space Telescope observations separated by 1.73 years. Dynamical models of the interaction between the planet and the belt indicate that the planet's mass is at most three times that of Jupiter for the belt to avoid gravitational disruption. The flux detected at 800 nm is also consistent with that of a planet with mass no greater than a few times that of Jupiter. The brightness at 600 nm and the lack of detection at longer wavelengths suggest that the detected flux may include starlight reflected off a circumplanetary disk, with dimension comparable to the orbits of the Galilean satellites. We also observed variability of unknown origin at 600 nm.
Fomalhaut's Debris Disk and Planet: Constraining the Mass of Fomalhaut b From Disk Morphology
E. Chiang, E. Kite, P. Kalas, J. R. Graham, M. Clampin
Following the optical imaging of the exoplanet candidate Fomalhaut b (Fom B ), we present a numerical model of how Fomalhaut's debris disk is gravitationally shaped by a single interior planet. The model is simple, adaptable to other debris disks, and can be extended to accommodate multiple planets. We find that to not disrupt the belt, Fom b must have a mass < 3 Jupiter masses. Previous mass constraints based on disk morphology rely on several oversimplifications. We explain why our constraint is more reliable. It is based on a global model of the disk that is not restricted to the planet's chaotic zone boundary. Moreover, we screen disk parent bodies for dynamical stability over the system age of 100 Myr, and model them separately from their dust grain progeny; the latter's orbits are strongly affected by radiation pressure and their lifetimes are limited to 0.1 Myr by destructive grain-grain collisions. The single planet model predicts that planet and disk orbits be apsidally aligned. Preliminary analysis of Fom b's space velocity does not bear this out. The disagreement might be resolved by having additional perturbers in the Fomalhaut system, for which there is independent evidence from the star's anomalous Hipparcos acceleration. Our upper mass limit of 3 Jupiter masses for Fom b is not affected by these considerations. The belt contains at least 3 Earth masses of solids that are grinding down to dust. Such a large mass in solids is consistent with Fom b having formed in situ.
From the first paper:
QUOTE
Though faint, Fomalhaut b is still one hundred times brighter than reflected light from a Jupiter-like planet at that radius from Fomalhaut.
QUOTE
Comparison between our photometric data and model planet atmosphere spectra indicate that Fomalhaut b may be a cooling Jovian-mass exoplanet with age 100-300 Myr. A planet atmosphere model with effective temperature Teff = 400 K and radius 1.2 RJ , for which the bolometric luminosity is 3.4 × 10−7 L⊙, reproduces the observed 0.8 μm flux.
QUOTE
Choosing a 400 K, 46 m s−2, 5× solar abundance model as a baseline, we can investigate the effects of gravity and composition using theoretical exoplanet model spectra. The elevated abundance set is chosen to be representative of solar system gas giants. The temperature and gravity of this model are a good match to a 200 Myr, 2.5 MJ exoplanet.
QUOTE
From 0.6 to 0.8 μm, Fomalhaut b is bluer than the models predict. Furthermore, between 2004 and 2006 Fomalhaut b became fainter by ∼0.5 mag at 0.6 μm . Photometric variability and excess optical emission cannot be explained by exoplanet thermal radiation alone. The 0.6 μm flux might be contaminated by H emission that is detected from brown dwarfs. Variable H emission might arise from a hot planetary chromosphere heated by vigorous internal convection, or trace hot gas at the inner boundary of a circumplanetary accretion disk, by analogy with magnetospheric emission from accreting T Tauri stars. If a circumplanetary disk is extended, the starlight it reflects might contribute to the flux detected at 0.6 and 0.8 μm. To explain our observed fluxes requires a disk radius ∼ 20−40 RJ, comparable to the orbital radii of Jupiter’s Galilean satellites.
QUOTE
As remarkably distant as Fomalhaut b is from its star, the planet might have formed in situ. The dust belt of Fomalhaut contains three Earth masses of solids in its largest collisional parent bodies. Adding enough gas to bring this material to cosmic composition would imply a minimum primordial disk mass of 1 MJ, comparable to the upper mass limit of Fomalhaut b. Alternatively, the planet might have migrated outward by interacting with its parent disk, or by gravitationally scattering off another planet in the system and having its eccentricity mildly damped by dynamical friction with surrounding disk material.
Bill
What I find particularly exciting about this discovery is that the imaged planet is so close to ours. It is within the realm of possibility to image a century long campaign of surveying the system, learning more about it, and eventually sending a multi-generational probe sent to investigate it and establish ground truths.
What a day to be alive!
What a day to be alive!
QUOTE
If a circumplanetary disk is extended, the starlight it reflects might contribute to the flux detected at 0.6 and 0.8 μm. To explain our observed fluxes requires a disk radius ∼ 20−40 RJ, comparable to the orbital radii of Jupiter’s Galilean satellites.
Are those calculations for a rocky circumplanetary disk or for a high albedo icy ring?
(Would a ring be stable out at the orbital radii of the Galilean satellites????)
QUOTE (Juramike @ Nov 14 2008, 07:50 PM) 
Are those calculations for a rocky circumplanetary disk or for a high albedo icy ring?
(Would a ring be stable out at the orbital radii of the Galilean satellites????)
(Would a ring be stable out at the orbital radii of the Galilean satellites????)
From the paper:
QUOTE
Now we consider that the planet is surrounded by dust grains analogous to circumplanetary rings. Since this is a flattened disk, the geometric cross section scales as cos(i), where i is the inclination to the line of sight (i = 0o is a face-on orientation). Consider that the main, optically thick rings of Saturn extend out to Saturn’s Roche radius, or about 2 planetary radii. If Fomalhaut b also harbored a ring system extending to its Roche radius, then p would be replaced by the ring cross section pr ∼ p × 22 × cos(66o) ∼ 1.6p. Assuming again Qs = 0.5, the apparent magnitude of the system would be mpr = 29.5 mag, or about 4.5 mag too faint compared to what is actually observed.
To make up for this shortcoming, the scattering surface area of the planet+ring system would have to increase by yet another factor of ∼60. This would correspond to about ∼16 planetary radii. If the effective albedo of the ring particles is closer to 0.1—and in fact outer solar system albedoes are typically this low—then the rings must extend to ∼35 planetary radii. An optically thick ring system that is 16–35 planetary radii large is better described as a protosatellite, circumplanetary disk. For example, the outermost Galilean satellite of Jupiter, Callisto, has a planetocentric distance of about ∼27 Jupiter radii. Regular satellites have prograde motion that indicates formation in situ around the planet.
To make up for this shortcoming, the scattering surface area of the planet+ring system would have to increase by yet another factor of ∼60. This would correspond to about ∼16 planetary radii. If the effective albedo of the ring particles is closer to 0.1—and in fact outer solar system albedoes are typically this low—then the rings must extend to ∼35 planetary radii. An optically thick ring system that is 16–35 planetary radii large is better described as a protosatellite, circumplanetary disk. For example, the outermost Galilean satellite of Jupiter, Callisto, has a planetocentric distance of about ∼27 Jupiter radii. Regular satellites have prograde motion that indicates formation in situ around the planet.
So an icy ring system with near 100% average albedo would need to extend to ~16 planetary radii, while a dark, dusty ring system with average albedo near 10% would need to extend to ~35 planetary radii.
It is implied that a Saturnian-type ring system is stable only out to the Roche radius, and a disk extending out to 10-20 times the Roche radius (as in this case) must be unstable and will collapse into larger solid satellites.
It will be interesting to know if the reflected light is polarized and how.
I have emails back and forth with NASA scientists on the upcomming kepler mission I had asked if the transiting jupiter with nice large moons could be detected and it is believed it can!
I have the science magazines articles on the discovery from my membership but they have a copyright! there are comments about nulling starlight and how they think they have detected a massive ring around Folmahuet B
another science article discuses nulling the star and the dust spetra to arrive at the spetra or temperature of the planet and then extrapolate the age of the new born planet and its mass.
the effect of the planet on folmahuets dust bands also arrives at the mass of the planet and of the dust bands.
so...............................no brown drarfs here
I have the science magazines articles on the discovery from my membership but they have a copyright! there are comments about nulling starlight and how they think they have detected a massive ring around Folmahuet B
another science article discuses nulling the star and the dust spetra to arrive at the spetra or temperature of the planet and then extrapolate the age of the new born planet and its mass.
the effect of the planet on folmahuets dust bands also arrives at the mass of the planet and of the dust bands.
so...............................no brown drarfs here
I wish they would give exoplanets "real" names, not just letters - a star as bright and well-known as Fomalhaut should have named planets.
QUOTE (Vultur @ Nov 15 2008, 07:44 PM)
I wish they would give exoplanets "real" names, not just letters - a star as bright and well-known as Fomalhaut should have named planets.
I agree. I think a good scheme would be naming extrasolar planets after fictional planets, with a restriction to books by dead authors.
However, wIser heads than mine point out that the expected discovery rate once Kepler and Gemini Planet Imager are running is so high that we would soon run out of appropriately dignified names. I have no problem with calling a small asteroid after a minor baseball player, but it seems wrong to do that to a giant planet.
A compromise might be to name planets orbiting stars closer than, say, 10 or 20 pc - the destinations - and leave the more distant worlds as letters for the moment.
(I am a junior member of the Fomalhaut science team and an author on both the theory & the observation papers).
- Edwin
QUOTE (edwinkite @ Nov 15 2008, 12:10 PM)
...(I am a junior member of the Fomalhaut science team and an author on both the theory & the observation papers).
- Edwin
- Edwin
Edwin, welcome to UMSF, and congratulations! What an exciting time in astronomy and the exploration of space. We've come a long way in the 30 years I've been interested in the sky. Hopefully we'll figure a way to send unmanned probes out fast enough to get 'on site' data within my lifetime.
Welcome, Ed! 
Nosy question here: Any details on the future observation campaign? (Wondering here if you guys plan to sweep all the nearby stars in any particular order). Also, what's the anticipated max detection distance for non-transiting superjovians (i.e, 150ly or so?)
Re the naming of names: I think keeping the current IAU convention would be fine for now. Once we can characterize these worlds would be the time for formal naming, IMHO, and surely SF provides a rich source. And just as a postscript, I certainly hope that when we map out an entire solar system the IAU will adopt the classic nomenclature of science fiction by assigning Roman numerals for each world based on its orbital radius or periastron, smallest to largest. The disadvantage of the letter convention is that it's based on order of discovery and therefore there's no continuity of order between systems.
Nosy question here: Any details on the future observation campaign? (Wondering here if you guys plan to sweep all the nearby stars in any particular order). Also, what's the anticipated max detection distance for non-transiting superjovians (i.e, 150ly or so?)Re the naming of names: I think keeping the current IAU convention would be fine for now. Once we can characterize these worlds would be the time for formal naming, IMHO, and surely SF provides a rich source. And just as a postscript, I certainly hope that when we map out an entire solar system the IAU will adopt the classic nomenclature of science fiction by assigning Roman numerals for each world based on its orbital radius or periastron, smallest to largest. The disadvantage of the letter convention is that it's based on order of discovery and therefore there's no continuity of order between systems.
QUOTE (Vultur @ Nov 15 2008, 01:44 PM)
I wish they would give exoplanets "real" names, not just letters - a star as bright and well-known as Fomalhaut should have named planets.
The polite thing to do would be to refer to an exoplanet by the name the residents use...
QUOTE (MizarKey @ Nov 15 2008, 10:13 PM)
Edwin, welcome to UMSF
Er, check the join date...
This is very exciting, hopefully the start of good things to come! Not that we have to complain about the exoplanet discoveries the last years, but still this is a big step and takes exoplanet-research to the next level.
One might ask, when do we know enough characteristics of a world to name it? There’s not a lot we know from most dwarf-planets, yet we named them. Also, we now have temperature maps, atmospheric data and even pictures of exoplanets, how much more do we have to know until we can name them?
Don’t get me wrong, I’m not saying we should name them yet, just asking what you think.
QUOTE
Re the naming of names: I think keeping the current IAU convention would be fine for now. Once we can characterize these worlds would be the time for formal naming, IMHO, and surely SF provides a rich source.
One might ask, when do we know enough characteristics of a world to name it? There’s not a lot we know from most dwarf-planets, yet we named them. Also, we now have temperature maps, atmospheric data and even pictures of exoplanets, how much more do we have to know until we can name them?
Don’t get me wrong, I’m not saying we should name them yet, just asking what you think.
Re: "Edwin, welcome to UMSF"
Member No. 6! A more dedicated lurker I have not seen!
QUOTE (SFJCody @ Nov 16 2008, 07:19 AM)
Er, check the join date...
Member No. 6! A more dedicated lurker I have not seen!
This visual discovery of a nearby planet sure whets the appetite for more! I can't wait for Terrestrial Planet Finder to get up and flying!
Being an armchair astronomer, I also like the idea of names, but I tend to think relevance/importance of the planet would eventually earn it a name. Placing arbitrary distance limits might be a problem if some really interesting planet is discovered that, for example, might become central to a new theory of solar system development. Rather than worry about what planets deserve a name, I'd rather see a naming system that hints at it's properties (analogous to the names of organic molecules, but with some leeway). So just rambling off the top of my head, maybe the 2nd syllable characterizes mass, and the last syllable characterizes temperature?
Being an armchair astronomer, I also like the idea of names, but I tend to think relevance/importance of the planet would eventually earn it a name. Placing arbitrary distance limits might be a problem if some really interesting planet is discovered that, for example, might become central to a new theory of solar system development. Rather than worry about what planets deserve a name, I'd rather see a naming system that hints at it's properties (analogous to the names of organic molecules, but with some leeway). So just rambling off the top of my head, maybe the 2nd syllable characterizes mass, and the last syllable characterizes temperature?
Re SF names: Yeah, it'll be decades IMHO before we can really tell enough about extrasolar planets to consider appropriate names from SF; it'll take instruments like TPF or better to do the job.
I posted this some time ago someplace on this board, but cannot find the location right now. Fortunately, I had another copy I could cut and paste.
Bill
QUOTE
It's a shame that no logical exoplanetary nomenclature has been adopted. Instead the system used for multiple stellar systems is being used, which causes confusion (is HDxxxxxxb a planet or a star?) and includes only two pieces of information: primary and order of discovery.
I would have suggested something like the following:
STAR NAME Pxx (YEAR DISCOVERERS)
Where "P" indicates a planetary-mass object and "xx" indicates ten times the base ten logarithm the orbital period, in tenths of a day (to allow for sub-single-day orbital periods).
For example, the current nomenclature for the 55 Cnc system looks like this (ordered by increasing planetary orbital period):
55 Cnc e
55 Cnc b
55 Cnc c
55 Cnc f
55 Cnc d
Whereas the example nomenclature would look like this (also ordered by increasing orbital period):
55 Cnc P14 (2004 McArthur, Endl, Cochran, Benedict, Fischer, Marcy, Butler, Naef, Mayor, Queloz, Udry, Harrison)
55 Cnc P22 (1996 Butler, Marcy, Williams, Hauser, Shirts)
55 Cnc P26 (2002 Marcy, Butler, Fischer, Laughlin, Voght, Henry, Pourbaix)
55 Cnc P34 (2005 Wisdom)
55 Cnc P47 (2002 Marcy, Butler, Fischer, Laughlin, Voght, Henry, Pourbaix)
Giving four pieces of information: primary, orbital period, year of discovery and discovery team.
In my opinion, this is a much better choice of nomenclature than the current one, which apparently was simply continued unchanged from the stellar-mass system nomenclature.
I would have suggested something like the following:
STAR NAME Pxx (YEAR DISCOVERERS)
Where "P" indicates a planetary-mass object and "xx" indicates ten times the base ten logarithm the orbital period, in tenths of a day (to allow for sub-single-day orbital periods).
For example, the current nomenclature for the 55 Cnc system looks like this (ordered by increasing planetary orbital period):
55 Cnc e
55 Cnc b
55 Cnc c
55 Cnc f
55 Cnc d
Whereas the example nomenclature would look like this (also ordered by increasing orbital period):
55 Cnc P14 (2004 McArthur, Endl, Cochran, Benedict, Fischer, Marcy, Butler, Naef, Mayor, Queloz, Udry, Harrison)
55 Cnc P22 (1996 Butler, Marcy, Williams, Hauser, Shirts)
55 Cnc P26 (2002 Marcy, Butler, Fischer, Laughlin, Voght, Henry, Pourbaix)
55 Cnc P34 (2005 Wisdom)
55 Cnc P47 (2002 Marcy, Butler, Fischer, Laughlin, Voght, Henry, Pourbaix)
Giving four pieces of information: primary, orbital period, year of discovery and discovery team.
In my opinion, this is a much better choice of nomenclature than the current one, which apparently was simply continued unchanged from the stellar-mass system nomenclature.
Bill
QUOTE
It's a shame that no logical exoplanetary nomenclature has been adopted.
False. Naming them in order of discovery is so far the only logical thing that has been thought up so far. Why? Because it's independent of knowledge of the planet. (i.e. orbital period, mass, etc).
Naming them in order of mass is illogical, as with the case of 55 Cnc, d would was discovered third, but is the most massive planet in the system. Naming planets in order of mass will cause one to have to rename planets. Very same goes for orbital period, etc.
QUOTE
Instead the system used for multiple stellar systems is being used, which causes confusion (is HDxxxxxxb a planet or a star?)
False. Star names are given capital letters, and planet names are given lower case letters.
HD xxxxxx B is the star.
HD xxxxxx Ab is the planet, orbiting the primary.
HD xxxxxx Bb is the planet, orbiting the secondary.
A possible source of confusion is for circumbinary planets, i.e., the planet at PSR B1620-26.
QUOTE
55 Cnc P14 (2004 McArthur, Endl, Cochran, Benedict, Fischer, Marcy, Butler, Naef, Mayor, Queloz, Udry, Harrison)
55 Cnc P22 (1996 Butler, Marcy, Williams, Hauser, Shirts)
55 Cnc P26 (2002 Marcy, Butler, Fischer, Laughlin, Voght, Henry, Pourbaix)
55 Cnc P34 (2005 Wisdom)
55 Cnc P47 (2002 Marcy, Butler, Fischer, Laughlin, Voght, Henry, Pourbaix)
55 Cnc P22 (1996 Butler, Marcy, Williams, Hauser, Shirts)
55 Cnc P26 (2002 Marcy, Butler, Fischer, Laughlin, Voght, Henry, Pourbaix)
55 Cnc P34 (2005 Wisdom)
55 Cnc P47 (2002 Marcy, Butler, Fischer, Laughlin, Voght, Henry, Pourbaix)
That's rather hard to memorize. The current scheme works, it's easy to reference what planet one is talking to.
Furthermore, it's dependent on values of the orbit, in this case the orbital period. When a new planet is discovered in a solar system, this causes the orbital solution for the system to change. HD xxxxxx b has, say, a mass of 1.5 M_j and a period of 2.4 yr. HD xxxxxx c is discovered, and it turns out that b, with the new orbital solution to the radial velocity data, has a mass of 1.3 M_j and a period of 2.2 yr. Now we'll have to re-name the planet, if we used that scheme.
Here's an example using, again, 55 Cnc
Current orbital fit to 55 Cancri
55 Cnc b = 0.115 AU
55 Cnc c = 0.24 AU
55 Cnc d = 5.77 AU
55 Cnc e = 0.038 AU
55 Cnc f = 0.781 AU
From:
A Planet at 5 AU Around 55 Cancri
Geoffrey W. Marcy et al. 2002
55 Cnc b = 0.115 AU
55 Cnc c = 0.241 AU
55 Cnc d = 5.9 AU
You can see that the orbital solution to 55 Cnc d has changed since then, due to the effect of the newly discovered planet, 55 Cnc f, which affected the signal of d in the RV data.
QUOTE
Giving four pieces of information: primary, orbital period, year of discovery and discovery team.
One of which is subject to change as more knowledge is gathered, as previously shown, meaning that this scheme can not be used.
The naming scheme for planets is virtually the same as the one used for stars, just with lower-case letters. The star naming scheme has worked fine for many years, as has the planet-naming scheme.
That's my view on that.
Wow. Are you always so confrontational in your posts?
I fail to see the problem with providing additional information in the official name of a planet. In current biological taxonomy, the year of description and name(s) of the describer are part of the official species (or higher taxon) name, and biologists seem to be fine with this -- for unofficial use they don't include the year and name information, but it is still part of the name for serious purposes. This planetary nomenclature was modeled in part on that system.
It is certainly true that published planetary periods occasionally change, but it would be easy to maintain an online list of planetary designations that have been changed. If an out-of-date designation is encountered, simply use it to look up the current designation. Problem solved.
I fail to see the problem with providing additional information in the official name of a planet. In current biological taxonomy, the year of description and name(s) of the describer are part of the official species (or higher taxon) name, and biologists seem to be fine with this -- for unofficial use they don't include the year and name information, but it is still part of the name for serious purposes. This planetary nomenclature was modeled in part on that system.
It is certainly true that published planetary periods occasionally change, but it would be easy to maintain an online list of planetary designations that have been changed. If an out-of-date designation is encountered, simply use it to look up the current designation. Problem solved.
QUOTE (Mongo @ Nov 16 2008, 04:33 PM)
Wow. Are you always so confrontational in your posts?
Ah, I apologize. =(
QUOTE
I fail to see the problem with providing additional information in the official name of a planet. In current biological taxonomy, the year of description and name(s) of the describer are part of the official species (or higher taxon) name, and biologists seem to be fine with this. This planetary nomenclature was modeled in part on that system.
Yeah, there's nothing wrong with adding the discoverer's name, that is absolute and doesn't change.
QUOTE
It is certainly true that published planetary periods occasionally change, but it would be easy to maintain an online list of planetary designations that have been changed. If an out-of-date designation is encountered, simply use it to look up the current designation. Problem solved.
That is true. It still entails more work and effort than the current naming system though.
Is there a (planned) system for naming the moons of exoplanets?
-Mike
-Mike
No.
Doesn't look like anything's been specifically defined, but if they follow Solar System conventions then they'll call extrasolar satellites by Roman numerals in order of discovery (ex. Upsilon Andromedae b-I for the first discovered natural satellite of that planet). Reference links:
http://planetarynames.wr.usgs.gov/append7.html
http://www.iau.org/public_press/themes/naming/
http://planetarynames.wr.usgs.gov/append7.html
http://www.iau.org/public_press/themes/naming/
It seems nomenclature of planets outside our solar system is as prone to emotion as those within it.
Consider it on the banned subjects list as of now. Find another board to have semantic arguments on off-topic subjects.
Consider it on the banned subjects list as of now. Find another board to have semantic arguments on off-topic subjects.
...slowly, the floodgates begin to open. The next few years should be purely fascinating!
Beta Pictoris planet finally imaged?
http://www.eso.org/public/outreach/press-r...8/pr-42-08.html
Edit: oops, didn't notice James posted same article
QUOTE
A team of French astronomers using ESO's Very Large Telescope have discovered an object located very close to the star Beta Pictoris, and which apparently lies inside its disc. With a projected distance from the star of only 8 times the Earth-Sun distance, this object is most likely the giant planet suspected from the peculiar shape of the disc and the previously observed infall of comets onto the star. It would then be the first image of a planet that is as close to its host star as Saturn is to the Sun.
http://www.eso.org/public/outreach/press-r...8/pr-42-08.html
Edit: oops, didn't notice James posted same article
Absolutely fascinating! Truly amazing! 
Simply stunning sequence of news, guys. We are very lucky to live this epoch...
I took the four images from original article:
http://www.eso.org/public/outreach/press-r...008/betapic.pdf
and I made a couple of elaborations in the right column, combining them in varius ways.
QUOTE (alan @ Nov 21 2008, 10:30 PM)
Beta Pictoris planet finally imaged?
I took the four images from original article:
http://www.eso.org/public/outreach/press-r...008/betapic.pdf
and I made a couple of elaborations in the right column, combining them in varius ways.
When I looked on the Extrasolar Planets listing on Friday there were 10 directly imaged planets listed, so this is presumably number 11. All except the Hubble one are hot objects imaged by thermal infrared, and the Hubble planet is only 'visible' because it is surrounded by a debris disc thirty times the size and 4 or 5 magnitudes brighter than itself. I wholeheartedly agree that this is a wonderful time - the opening of a new window on our cosmic surroundings. We have great things to look forward to here, including the first reflected light image of a cold 'Jupiter' without a disc around it.
QUOTE (ngunn @ Nov 22 2008, 05:13 PM)
We have great things to look forward to here, including the first reflected light image of a cold 'Jupiter' without a disc around it.
My bet is Eps Eri b.
Direct Image Of Extrasolar Planet
http://www.youtube.com/watch?v=aXKz4nxyPqw...feature=related
Does anyone have the full video to this link above!!!???
It gets cut off just as it gets better.
http://www.youtube.com/watch?v=aXKz4nxyPqw...feature=related
Does anyone have the full video to this link above!!!???
It gets cut off just as it gets better.
Thanks!
Has Fomalhaut had any wobbles detected?
No. Fomalhaut b orbits the star every 870 or so years. It would take that long to observe one complete wobble from this planet.
Fomalhaut is also very bright, making it a difficult astrometry target, I would guess.
Fomalhaut is also very bright, making it a difficult astrometry target, I would guess.
QUOTE (Hungry4info @ Nov 24 2008, 10:16 PM)
Fomalhaut is also very bright, making it a difficult astrometry target, I would guess.
Why? I think is exactly the opposite: higher the luminosity, better the S/N ratio for both astrometry and spectroscopy...
QUOTE (dilo @ Nov 25 2008, 12:15 AM)
Why? I think is exactly the opposite: higher the luminosity, better the S/N ratio for both astrometry and spectroscopy...
I'm unsure how the FGS works. Would Fomalhaut's brightness saturate the instrument?
Yup. FGS normally observes mag +8 and fainter. You may observe brighter targets using a neutral density filter*, up to mag +3.
*Not recommended (complicates calibration).
*Not recommended (complicates calibration).
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