<p>Is one lightcurve containing a dip in brightness obtained from the transit method sufficient to obtain or estimate the orbital period of an exoplanet - such that one (first) observation could be used to reliably schedule a second observation for confirmation in advance?</p>

CC BY-SA 4.0
2023-01-20T23:44:13.117Z
No. You don’t know the size of the object, its (absolute) speed (as opposed to angular), its distance, etc. You don’t even know *if* the object will pass again in front of the star!
Pierre Paquette
CC BY-SA 4.0
2023-01-21T01:24:04.040Z
@PierrePaquette [After only one eclipse of its X-ray bright primary, how can astronomers estimate the first extragalactic exoplanet's period to be about 70 years?](https://astronomy.stackexchange.com/q/47224/7982)
uhoh
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2023-01-21T02:14:01.623Z
@uhoh They make a good case there, but astronomers might not have all such relevant information about the observed event and its associated star…
Pierre Paquette
CC BY-SA 4.0
2023-01-21T02:14:25.283Z
Oh! and this is why I commented instead of answered… ;-)
Pierre Paquette
CC BY-SA 4.0
2023-01-21T05:53:28.430Z
@PierrePaquette it's a proof of concept but this question needs a complete answer based on different cases (as you have pointed out it depends a lot on the information available to try to model the primary) which I'm not really up to.
uhoh
CC BY-SA 4.0
2023-01-21T08:10:23.150Z
Me neither… Sorry!
Pierre Paquette
<mathematics><transits-other-than-sun>
It is possible to estimate an exoplanets' orbital period from just one transit?
2080
# It is possible to estimate an exoplanets' orbital period from just one transit?

(Asked by: username_0 on 2023-01-20)

Is one lightcurve containing a dip in brightness obtained from the transit method sufficient to obtain or estimate the orbital period of an exoplanet - such that one (first) observation could be used to reliably schedule a second observation for confirmation in advance?

**Tags:** mathematics, transits-other-than-sun
> **Comments:**
> **username_1**: No. You don’t know the size of the object, its (absolute) speed (as opposed to angular), its distance, etc. You don’t even know *if* the object will pass again in front of the star!  
> **username_2**: @PierrePaquette [After only one eclipse of its X-ray bright primary, how can astronomers estimate the first extragalactic exoplanet's period to be about 70 years?](https://astronomy.stackexchange.com/q/47224/7982)  
> **username_1**: @uhoh They make a good case there, but astronomers might not have all such relevant information about the observed event and its associated star…  
> **username_1**: Oh! and this is why I commented instead of answered… ;-)  
> **username_2**: @PierrePaquette it's a proof of concept but this question needs a complete answer based on different cases (as you have pointed out it depends a lot on the information available to try to model the primary) which I'm not really up to.  
> **username_1**: Me neither… Sorry!  

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## 0 answers

