Astrophysical timing derived from photometric relative phase measurements of periodic stellar variability

Patent metadata

Field	Value
Publication number	US-12517468-B2
Application number	US-202318214010-A
Country	US
Kind code	B2
Filing date	Jun 26, 2023
Priority date	Jun 26, 2023
Publication date	Jan 6, 2026
Grant date	Jan 6, 2026

Abstract

A method for deriving an independent current time estimate from celestial sources comprising: providing a reference measurement for a variable-intensity celestial source, wherein the reference measurement comprises the celestial source's photometric structure at a known time, at a known stellar period, and at a known periodic phase; creating a phase-folded light curve for the celestial source; measuring an intensity of the celestial source at a subsequent time; comparing the measured intensity of the celestial source to the phase-folded light curve to derive a set of possible phase differences, wherein each possible phase difference corresponds to a potential derived time based on the known time and the known stellar period of the reference measurement; and analyzing the set of possible phase differences to derive the current astrophysical time.

First claim

I claim:

1 . A method for deriving an independent current time estimate from celestial sources comprising:
providing a reference measurement for a variable-intensity celestial source, wherein the reference measurement comprises the celestial source's photometric structure at a known time, at a known stellar period, and at a known periodic phase; creating a phase-folded light curve for the celestial source; measuring an intensity of the celestial source at a subsequent time; comparing the measured intensity of the celestial source to the phase-folded light curve to derive a set of possible phase differences, wherein each possible phase difference corresponds to a potential derived time based on the known time and the known stellar period of the reference measurement; and analyzing the set of possible phase differences to derive the current astrophysical time.

2 . The method of claim 1 , wherein the celestial source is selected from the group consisting of:
eclipsing binary star systems, δ Scuti stars, and resident space objects orbiting the Earth.

3 . The method of claim 1 , wherein the celestial source is an eclipsing binary star system.

4 . The method of claim 1 , wherein the analyzing step comprises:
selecting a single phase difference from the first set of possible phase differences that most closely aligns with an expected astrophysical time.

5 . The method of claim 4 , wherein the selecting step is performed by a human.

6 . The method of claim 4 , wherein the selecting step is performed by a computer.

7 . The method of claim 4 , further comprising:
performing the providing, creating, measuring, and comparing steps of claim 1 for each of the plurality of different variable-intensity celestial sources; and wherein the analyzing step comprises analyzing the set of possible phase differences from each of the plurality of different variable-intensity celestial sources to derive the current astrophysical time.

8 . The method of claim 7 , further comprising:
measuring an intensity of each of the plurality of different variable-intensity celestial sources at a second subsequent time; comparing the measured intensity of each of the plurality of different variable-intensity celestial sources to a corresponding phase-folded light curve at the subsequent time and at the second subsequent time to derive a set of possible phase differences for each of the plurality of different variable-intensity celestial sources; and analyzing the sets of possible phase differences to derive the current astrophysical time.

9 . The method of claim 7 , wherein the reference measurements come from published ephemerides.

10 . The method of claim 9 , wherein the measuring steps are performed with a mobile photon collection device.

11 . The method of claim 1 , wherein the current astrophysical time is derived only from the collected photons and a database of reference measurements.

12 . A method for deriving a current astrophysical time comprising:
creating, with a computer, a database of reference measurements, wherein each reference measurement corresponds to a separate celestial source having a periodically-varying brightness, and wherein each reference measurement includes data about the corresponding celestial source's photometric structure at a given time, at a given stellar period, and at a known periodic phase; creating a phase-folded light curve for each celestial source having a reference measurement in the database; at a first subsequent time, collecting photons from a plurality of the celestial sources having a reference measurement in the database to create a first target measurement for each of the plurality of celestial sources at the first subsequent time; comparing each first target measurement to a corresponding phase-folded light curve to derive a first set of possible phase differences, wherein each possible phase difference corresponds to a potential derived time based on the given time and the given stellar period of the corresponding reference measurement; and analyzing the first set of possible phase differences to derive the current astrophysical time.

13 . The method of claim 12 , wherein the analyzing step comprises:
selecting a single phase difference from the first set of possible phase differences that most closely aligns with an expected astrophysical time.

14 . The method of claim 13 , wherein the selecting step is performed by a human.

15 . The method of claim 13 , wherein the selecting step is performed by a computer.

16 . The method of claim 12 , wherein the current astrophysical time is derived only from the collected photons and the database of reference measurements.

17 . The method of claim 12 , wherein the plurality of celestial sources is selected from one or more of the group consisting of: eclipsing binary star systems, δ Scuti stars, and resident space objects orbiting the Earth.

18 . The method of claim 12 , wherein the plurality of celestial sources consists of a single eclipsing binary star system.

19 . The method of claim 12 , further comprising:
at a second subsequent time, collecting photons from the plurality of the celestial sources having a reference measurement in the database to create a second target measurement for each of the plurality of celestial sources at the second subsequent time; comparing each second target measurement to a corresponding phase-folded light curve to derive a second set of possible phase differences, wherein each possible phase difference corresponds to a potential derived time based on the given time and the given stellar period of the corresponding reference measurement; and wherein the analyzing step further comprises analyzing the first and second sets of possible phase differences for each of the plurality of celestial sources to derive the current astrophysical time.

20 . The method of claim 12 , wherein the database of reference measurements is compiled, at least in part, from published ephemerides.

Assignees

• Us Navy

Inventors

• Mellon Samuel Nicholas

Classifications

• G01C21/02

  by astronomical means (G01C21/24, G01C21/26 take precedence) · CPC title

• G04F13/02 Primary

  using optical means · CPC title

• G04G99/00 Primary

  Subject matter not provided for in other groups of this subclass · CPC title