Timing the Stars: James Webb Telescope's Precision
JWST proves its timing capabilities while observing cosmic events.
A. W. Shaw, D. L. Kaplan, P. Gandhi, T. J. Maccarone, E. S. Borowski, C. T. Britt, D. A. H. Buckley, K. B. Burdge, P. A. Charles, V. S. Dhillon, R. G. French, C. O. Heinke, R. I. Hynes, C. Knigge, S. P. Littlefair, Devraj Pawar, R. M. Plotkin, M. E. Ressler, P. Santos-Sanz, T. Shahbaz, G. R. Sivakoff, A. L. Stevens
― 5 min read
Table of Contents
- What Are We Timing?
- ZTF J1539: Our Cosmic Stopwatch
- The Setup
- Timing Systematics-What’s That?
- Timing Accuracy: The Results Are In
- The Curious Case of the Eclipse
- Starspots or Magnetic Fields?
- Getting the Data
- A Two-part Dance
- The Mystery Deepens
- Bringing in Backup
- The Ground Truth
- Looking Ahead
- What’s Next?
- Conclusion: A Cosmic Symphony
- Original Source
- Reference Links
When it comes to space telescopes, the James Webb Space Telescope (JWST) is a superstar. Though it wasn’t built to track fast-changing cosmic events, folks have been able to use it for Timing studies that happen in a blink of an eye-figuratively speaking. Scientists hoped that by keeping an eye on its timing system, they could get sub-second timing from JWST. And guess what? It worked!
What Are We Timing?
So, what’s the big deal with timing in space? Astronomers study all sorts of starry things, and some of them, like stars that wobble or blink, change their brightness quickly. This means they need precise timing to figure out what’s going on. JWST can help with this. It can help measure the timing of various events like the light from a dying star or when a planet passes in front of its star.
ZTF J1539: Our Cosmic Stopwatch
In this research, JWST was pointed at a pair of white dwarf stars involved in a dance. This system is called ZTF J153932.16+502738.8. Think of them as two old friends catching up, but instead of just chatting, they take turns eclipsing each other. The goal was to use the regularity of their Eclipses to check the accuracy of JWST's timing.
The Setup
To get the best timing results, scientists set up observations over two long sessions. During these sessions, JWST focused on ZTF J1539, observing it while it did its thing. The observations provided the researchers with a treasure trove of data to figure out how accurate JWST's clock was.
Timing Systematics-What’s That?
In simple terms, timing systematics refers to the errors or differences that can mess with your timing data. It’s like trying to catch a fly with your hands-if your timing isn’t just right, you’re going to miss! The scientists worked hard to control these errors so they could really see what JWST was capable of.
Timing Accuracy: The Results Are In
After observing ZTF J1539, researchers found that JWST’s clock was pretty darn accurate! When they measured the timing, they found that they could indeed get results down to a millisecond. This was a big deal since before this, they were aiming for a full second of accuracy.
The Curious Case of the Eclipse
During these observations, something peculiar happened. The primary eclipse of ZTF J1539 didn’t look symmetrical in the infrared light. Imagine a perfectly round pizza suddenly being cut into an odd shape-one side looks fuller than the other! This peculiar shape got researchers wondering what could be causing this asymmetry.
Starspots or Magnetic Fields?
One theory is that starspots on the surface of the cooler star might be causing the odd shape. Starspots are like sunspots but on other stars. They could affect how the light comes out from the eclipsing star, giving us that funny look. Another possibility is a magnetic field creating interesting effects in this pair of old buddies.
Getting the Data
The researchers used JWST's Near Infrared Camera (NIRCam) for observations. They took images in different colors (or wavelengths) of light to gather data. Each image held clues about the eclipsing stars, and by analyzing them, scientists pieced together a picture of what was happening.
A Two-part Dance
The team observed ZTF J1539 across two distinct epochs, or time periods. Each epoch had its own characteristics, and the data collected were like two different performances of the same ballet.
Epoch 1: The first round of observations showed that everything was running smoothly, with JWST’s clock measuring time accurately.
Epoch 2: The second round raised eyebrows among scientists. The asymmetry in the eclipse profile hinted at something more profound happening in the system.
The Mystery Deepens
The odd timing during the second epoch required further exploration. The researchers couldn’t just assume things were out of whack with JWST’s clock. After all, it was already a reliable device. Instead, they needed to investigate if the timing inconsistency was just an anomaly or if it hinted at something more intriguing about the star system itself.
Bringing in Backup
To check their results, the researchers turned to ground-based telescopes that had been watching ZTF J1539 over the years. These telescopes had better timing accuracy, and comparing their results could help verify whether JWST’s measurements were off or just revealing a new aspect of the system.
The Ground Truth
The ground-based observations showed that the timing inconsistency was indeed real. The Light Curves showed comparable timing, reinforcing the idea that something unique was happening with ZTF J1539. This was not just a case of JWST making a mistake, but rather an interplay of cosmic mysteries revealing themselves.
Looking Ahead
The accurate timing measurements from JWST offer a new frontier for astronomers. They can now examine other fast-changing objects in the universe with greater precision. Whether it’s black holes or rare events like neutron star mergers, JWST is ready to help scientists time their cosmic clock with newfound accuracy.
What’s Next?
Moving forward, researchers hope to apply the lessons learned from ZTF J1539 to future observations. The findings suggest that JWST and its timing capabilities can open new doors in astrophysics. The team plans to explore more variable objects and seek additional mysterious cosmic dance partners.
Conclusion: A Cosmic Symphony
In the end, calibrating JWST’s clock while observing ZTF J1539 has shown that timing in astronomy isn’t just about precision-it’s also about the stories the stars tell us. As we continue to unravel these cosmic tales, we know that JWST will be right there, ticking away while peering into the vast unknown, helping us understand the universe and our place in it, one millisecond at a time.
Title: Calibrating the clock of JWST
Abstract: JWST, despite not being designed to observe astrophysical phenomena that vary on rapid time scales, can be an unparalleled tool for such studies. If timing systematics can be controlled, JWST will be able to open up the sub-second infrared timescale regime. Rapid time-domain studies, such as lag measurements in accreting compact objects and Solar System stellar occultations, require both precise inter-frame timing and knowing when a time series begins to an absolute accuracy significantly below 1s. In this work we present two long-duration observations of the deeply eclipsing double white dwarf system ZTF J153932.16+502738.8, which we use as a natural timing calibrator to measure the absolute timing accuracy of JWST's clock. From our two epochs, we measure an average clock accuracy of $0.12\pm0.06$s, implying that JWST can be used for sub-second time-resolution studies down to the $\sim100$ms level, a factor $\sim5$ improvement upon the pre-launch clock accuracy requirement. We also find an asymmetric eclipse profile in the F322W2 band, which we suggest has a physical origin.
Authors: A. W. Shaw, D. L. Kaplan, P. Gandhi, T. J. Maccarone, E. S. Borowski, C. T. Britt, D. A. H. Buckley, K. B. Burdge, P. A. Charles, V. S. Dhillon, R. G. French, C. O. Heinke, R. I. Hynes, C. Knigge, S. P. Littlefair, Devraj Pawar, R. M. Plotkin, M. E. Ressler, P. Santos-Sanz, T. Shahbaz, G. R. Sivakoff, A. L. Stevens
Last Update: 2024-11-04 00:00:00
Language: English
Source URL: https://arxiv.org/abs/2411.02238
Source PDF: https://arxiv.org/pdf/2411.02238
Licence: https://creativecommons.org/licenses/by/4.0/
Changes: This summary was created with assistance from AI and may have inaccuracies. For accurate information, please refer to the original source documents linked here.
Thank you to arxiv for use of its open access interoperability.
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