Three exocomets found circling Beta Pictoris
The uncertainty of science: By analyzing data from the new space telescope TESS, astronomers think they have identified three exocomets orbiting the nearby star Beta Pictoris.
Why do I label this uncertain? Let the scientists themselves illustrate my doubt:
Sebastian Zieba, Master’s student in the team of Konstanze Zwintz at the Institute of Astro- and Particle Physics at the University of Innsbruck, discovered the signal of the exocomets when he investigated the TESS light curve of Beta Pictoris in March this year. “The data showed a significant decrease in the intensity of the light of the observed star. These variations due to darkening by an object in the star’s orbit can clearly be related to a comet,” Sebastian Zieba and Konstanze Zwintz explain the sensational discovery.
The press release provides no other information about why they think this darkening is because of comets rather than exoplanets or some other phenomenon. Based on this alone, I find this report very doubtful and highly speculative.
In related news, astronomers now claim they have detected eighteen more Earth-sized exoplanets in the data produced by Kepler, and they have done so by applying new algorithms to the data.
Large planets tend to produce deep and clear brightness variations of their host stars so that the subtle center-to-limb brightness variation on the star hardly plays a role in their discovery. Small planets, however, present scientists with immense challenges. Their effect on the stellar brightness is so small that it is extremely hard to distinguish from the natural brightness fluctuations of the star and from the noise that necessarily comes with any kind of observation. René Heller’s team has now been able to show that the sensitivity of the transit method can be significantly improved, if a more realistic light curve is assumed in the search algorithm. “Our new algorithm helps to draw a more realistic picture of the exoplanet population in space,” summarizes Michael Hippke of Sonneberg Observatory. “This method constitutes a significant step forward, especially in the search for Earth-like planets.”
This makes sense, but it must be understood that these are only candidate exoplanets, unconfirmed as yet. I would not be surprised if a majority are found to be false positives.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
The uncertainty of science: By analyzing data from the new space telescope TESS, astronomers think they have identified three exocomets orbiting the nearby star Beta Pictoris.
Why do I label this uncertain? Let the scientists themselves illustrate my doubt:
Sebastian Zieba, Master’s student in the team of Konstanze Zwintz at the Institute of Astro- and Particle Physics at the University of Innsbruck, discovered the signal of the exocomets when he investigated the TESS light curve of Beta Pictoris in March this year. “The data showed a significant decrease in the intensity of the light of the observed star. These variations due to darkening by an object in the star’s orbit can clearly be related to a comet,” Sebastian Zieba and Konstanze Zwintz explain the sensational discovery.
The press release provides no other information about why they think this darkening is because of comets rather than exoplanets or some other phenomenon. Based on this alone, I find this report very doubtful and highly speculative.
In related news, astronomers now claim they have detected eighteen more Earth-sized exoplanets in the data produced by Kepler, and they have done so by applying new algorithms to the data.
Large planets tend to produce deep and clear brightness variations of their host stars so that the subtle center-to-limb brightness variation on the star hardly plays a role in their discovery. Small planets, however, present scientists with immense challenges. Their effect on the stellar brightness is so small that it is extremely hard to distinguish from the natural brightness fluctuations of the star and from the noise that necessarily comes with any kind of observation. René Heller’s team has now been able to show that the sensitivity of the transit method can be significantly improved, if a more realistic light curve is assumed in the search algorithm. “Our new algorithm helps to draw a more realistic picture of the exoplanet population in space,” summarizes Michael Hippke of Sonneberg Observatory. “This method constitutes a significant step forward, especially in the search for Earth-like planets.”
This makes sense, but it must be understood that these are only candidate exoplanets, unconfirmed as yet. I would not be surprised if a majority are found to be false positives.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
From the article: “The data showed a significant decrease in the intensity of the light of the observed star. These variations due to darkening by an object in the star’s orbit can clearly be related to a comet”
Clearly, that must be one big comet (or three)!
If memory serves me correctly, astronomers wanted to see three transits before declaring a dimming event to be from a planet. This was so that they can verify not only the orbital period but the dimming phenomenon itself. If the dimming profile is the same then it is almost certainly an actual object rather than a phenomenon of the noise in the data, and if the period is the same then it is almost certainly the same object.
verification can come from observing the spectral shift of the stars as their planets orbit them, which is the method used for finding the first few exoplanets. However, it is far more difficult to observe the spectra of thousands of stars than it is to gather the intensity of the light of thousands of stars.