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alberto91

The Habitable Exoplanet Hunting Project

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Hi all!

We are looking for more observatories and amateur astronomers who might want to join the project.

The Habitable Exoplanet Hunting Project is a worldwide network of amateur astronomers searching for new potentially habitable exoplanets. I am coordinating over 20 observatories located in 5 continents.

We are searching for habitable exoplanets around non-flare G, K and M-type stars located within 100 ly.

The stars we are monitoring already have known transiting exoplanets, but none of them are potentially habitable.

We are monitoring each star 24/7 for several months. By doing so, we believe that the chances of finding an exoplanet increase for particular targets. Moreover, we are focusing on stars closer than 100 light years because, on the one hand, the closest habitable exoplanets will be the first destinations of interstellar missions and, on the other, because very few nearby habitable exoplanets around G and K-type stars have been discovered: only 2 of them.

The number of potentially habitable exoplanets that we could discover is, in theory, around 25. This calculation was obtained by taking into account the number of non-flare stars within 100 light years and the percentage of them that should show transits in the habitable zone.

Each observatory observes the same star and, when the transit of a hypothetical habitable exoplanet becomes unlikely, we move to another star.

Within 100 light years, we only found 10 non-flare G, K and M-type stars with known transiting exoplanets not potentially habitable.

Big telescopes are not necessary, but CCD cameras with a resolution of at least 16 bits are advisable because we are searching for exoplanets that produce a change of brightness in the star of around 0.1%.

If you are interested, feel free to contact me.

More info: https://youtu.be/0A7gEaewOws

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Your plan is to detect 1 mmag transits.   This level of precision sounds tough to me. Have you checked with any of the experienced amateurs already doing this sort of work if this is achieveable?

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18 hours ago, robin_astro said:

Your plan is to detect 1 mmag transits.   This level of precision sounds tough to me. Have you checked with any of the experienced amateurs already doing this sort of work if this is achieveable?

Yes, all of them have been able to detect 0.1% transits.

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I would have thought that such project needed some sort of website to support it?

Do you have such a website / web based service to aggregate data and coordinate observations?

That way you can possibly attract much more "short term" observations and still cover full time period and all the stars. There will be much more people willing to dedicate an hour or two a week of their observing time for this project than those that are willing to participate "full time".

Not sure if recommending at least 16bit CCD sensor is good way to approach this. CMOS sensors are becoming more and more popular, and most of them have "only" 12 or 14 bits, but much lower read noise. I'm fairly certain that they can be used as effectively as 16bit CCDs.

What sort of magnitude are potential star candidates? Registering drop of 0.1% in brightness will depend on target star brightness in the first place, and also time taken to transit. If you provide a range of values for that data, it would be rather easy to calculate needed exposure lengths (or stacks) depending on scope aperture and recording resolution (and need for binning) to get certain SNR needed to make a detection. Above website could facilitate online calculator for this where people wanting to participate could select target star (or be assigned one depending on their location and designated observing time, with coverage taken into account) and specify their equipment and it would provide directions for observation - needed exposure(s), any stacking, proper calibration and finally way to submit their data - either for further processing / analysis or people could download software to analyze their subs on their computers and just submit results.

Anyway interesting project, would love to participate but I don't have permanent obsy and I'm in general lacking observation time these days due to shortage of free time.

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On 14/07/2019 at 17:50, alberto91 said:

Yes, all of them have been able to detect 0.1% transits.

Can you supply evidence of this ? Detecting a 0.1% transit with a known timing using an amateur setup from the ground with a reasonable confidence level is already (surprisingly) impressive.  I would want to see evidence  though that detecting a transit with unknown timing of this depth from potentially months of background data collected from different sites is likely to be possible with a reasonable confidence level.  

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2 hours ago, vlaiv said:

What sort of magnitude are potential star candidates?

Hi Vlaiv,

A quick check suggests at 100 lyr a main sequence G star would be Vmag ~7.5  an M dwarf would be ~13.5. 

https://sites.uni.edu/morgans/astro/course/Notes/section2/spectraltemps.html

http://www.calctool.org/CALC/phys/astronomy/star_magnitude

The magnitude is not so much the problem though. It should be possible to get the required SNR (2000 to detect 0.1% at 95% confidence) in 5 min total exposure for a mag 11 star and 200mm aperture

http://spiff.rit.edu/richmond/signal.shtml

The main problem is likely to be identifying transits against background systematic variations at the mmag level with the same timescales as the suspected transits, particularly where potential events extend over different observers.

Cheers

Robin

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14 minutes ago, robin_astro said:

The main problem is likely to be identifying transits against background systematic variations at the mmag level with the same timescales as the suspected transits, particularly where potential events extend over different observers.

 

This could be checked by prospective observers by measuring a known non variable over an extended period

Edited by robin_astro

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1 hour ago, robin_astro said:

Hi Vlaiv,

A quick check suggests at 100 lyr a main sequence G star would be Vmag ~7.5  an M dwarf would be ~13.5. 

https://sites.uni.edu/morgans/astro/course/Notes/section2/spectraltemps.html

http://www.calctool.org/CALC/phys/astronomy/star_magnitude

The magnitude is not so much the problem though. It should be possible to get the required SNR (2000 to detect 0.1% at 95% confidence) in 5 min total exposure for a mag 11 star and 200mm aperture

http://spiff.rit.edu/richmond/signal.shtml

The main problem is likely to be identifying transits against background systematic variations at the mmag level with the same timescales as the suspected transits, particularly where potential events extend over different observers.

Cheers

Robin

Well, this certainly shows that one would be able to measure some of the stars. Here is my calculation from same sources:

Magnitude range: up to 16.83 (M8 type star - absolute mag 14.4, distance 100ly), or roughly up to mag17

With my setup, in my location, I would be able to achieve SNR of 2000 up to mag9 stars in 5 minutes - F/8 8" RC, mag18.5 skies, 0.5QE, 3.8um pixel binned x2 with read noise 3.4e (original 1.7e, software binning) - sampling rate ~1"/px, around 2" FWHM.

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Out of curiosity I ran test for "best" amateur equipment, and I believe 100ly radius is a bit optimistic.

In pristine mag22 skies right at zenith with exceptional transparency, with superb seeing FWHM 1.5, with 20" scope and probably non existent CCD (average QE 0.7, read noise 5e giving 1"/px on such focal length - meaning huge pixels), SNR of 2000 can be had in half an hour exposure (I guess that transits will be limited in time and you need at least couple of measurements to get the curve) down to mag14 source.

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You can see typical transits on the TRESCA website (a project looking for variations in transit timing for known transiting exoplanets)

http://var2.astro.cz/EN/tresca/index.php?lang=en

The typical 1 sigma residual per point in the recent measurements looks to be an impressive 2-5 mmag.  Based on this it would probably be just possible to detect a known transit at 0.1%  but whether a transit of this depth could be pulled out of a several month long data series where the period and timing is unknown is I would say debatable

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