🔭 ✨Boring Astronomy: an unforgettable week (2025 edition)✨🔭

Behind the Scenes of the Science of the Cosmos

I am Alessandro. I have been in astronomy since 2002.
If you are eager to have a playful attitude towards astronomy; you want to grow your interest in this science and you want to know how astronomy works “behind the scenes”, this is the place for you.
I am planning on sending this Newsletter every Sunday.
Mistakes will be made; I count on your feedback to make this newsletter a better place and provide you with increasingly better content.
You can follow my vlog on TikTok or my YouTube Channel .
You can find Boring Astronomy’s material on Etsy.

📰 This week in Astronomy

The whole purpose of Boring Astronomy is to cut through the hype but it is difficult to ignore the noise that the revelation of the first images of the Vera Rubin Observatory made.
During the next week, I will upload a video to the YouTube channel to go to the core of this announcement.

I attended the meeting of the European Astronomical Society. A YouTube video on this experience will come out soon.

Vasto Accretion Meeting, Vasto, Italy, 23 - 27 June 2025

About 100 astronomers met in Vasto, Italy, to share the latest news about accretion physics around white dwarfs, neutron stars and stellar mass black holes.

Check the website because the presentations may be shared sometime after the meeting.

European Astronomical Society Annual Meeting,University College Cork. Cork, Ireland, 23 – 27 June 2025

Last Monday, at 9h00, about 1500 astronomers were in the University College of Cork looking for the room of the symposium they wanted to attend. A difficult task since the choice was between 16 different symposia happening at the same time.

The massive attendance and the varied offer made a very exciting event.

📚😃Astronomical paper of the Week

Everyday, I check the papers which are published on astro-ph.
This is a good way to keep in touch with the latest news.
A word of caution: many of the papers published there have not passed the refereeing process.
In this section, I pick a paper for you.
If you want me to comment on a paper, just send it to me by the Friday prior to the publication of the newsletter.

Here is a series of papers which nearly made it to "astronomical paper of the week":

• The investigation of 84 TESS totally eclipsing contact binaries

• On accretion in the polar V379 Vir

• X-ray and Optical Analysis of the Prototype Polar AN UMa

• FuGa3D: Fast full-sky analysis of Galaxy catalogs in 3D

• The completeness of the open cluster census towards the Galactic anticentre

• Towards Modelling AR Sco: Calibration -- Reproducing High-Energy Pulsar Emission and Testing Convergence to Aristotelian Electrodynamics

• Symbiotic star candidates in Gaia Data Release 3

• James Webb Space Telescope observations of the white dwarf cooling sequence of 47 Tucanae

• A Joint JWST and HST View of Omega Centauri: Multiple Stellar Populations and Their Kinematics

• Hunting for UVdim stars in Galactic Open clusters. Clues from ultraviolet photometry

This week’s paper is "(Re)-Defining Planets -- the Fundamental Plane of Planets (Jagadeesh et al.)"

🤩Why is it interesting?

Astronomers love definitions. The definition of "star" or "galaxy" is very complicated.

The general public tends to remember the definition of planet in the Solar System approved by the International Astronomical Union. The definition was made necessary by the discovery of objects beyond the orbit of Pluto. An important consequence of that definition was that Pluto was excluded by the list of "planets" but it was promoted to be the prototype of a new class (the "dwarf planets").

Extrasolar planets (i.e. planets orbiting stars which are not the Sun) are left out of this definition.

The heated discussions about definitions are very entertaining. Yet, in most cases, these discussions carry some interesting information.

🤨 What is the paper about?

Unsurprisingly, the paper starts off complaining about the IAU definition of planet both because of some issues within the Solar System (which is a fair comment) and because it does not work for exoplanets (which is logical because this definition was never intended to do it).

The authors embark on the discussion on the definition of planet based on three measurable numbers: the mass, the radius and the moment of inertia.

Moons, asteroids and rocky planets provide a lower limit for the range of masses being considered in this study.

The low mass limit of the moment of inertia vs mass plot. Note the position of Pluto. Figure 1 of this paper.

Perhaps my favourite sentence is

Pluto’s debate of being or not being a planet can be fixed using Fig 3. According to it, we confirm that Pluto has most similar proper- ties with moons

Their figure 3 is the same as their figure 1 but removing the "rocky exoplanets" and, indeed, Pluto falls clearly among the moons. Is Pluto a moon of the Sun?

Things get really difficult when getting to the upper limit. Most of us grew up with the definition of Jupiter as a "failed star" and, indeed, the limit between brown dwarfs and giant planets is blurry.

Same as the previous plot but for giant planets, brown dwarfs and low mass stars. Figure 5 of the paper.

Radius vs mass plane; not eh position of the low mass stars and the planets of the Solar System. Figure 6 of the paper.

The authors define a planet as "a celestial spherical object, bound to a star or unbound, that lies on the fundamental planetary plane, within a mass range between 10^23 Kg to 2.5 × 10^28 Kg"

In the appendix, the authors try to touch upon the definition of star, getting in very rough waters.

The effort is certainly worthy but its success is debatable. I sympathise with the idea of providing a physically constrained definition for planets in and out of the Solar System. The paper is submitted to a journal and we will see if it gets accepted.

🤖🖥AI in Astronomy

Artificial Intelligence is entering all aspects of our lives. In this section, we try to share useful prompts, use cases, and reflections which may help you using AI in a constructive and engaging way.

Two papers on AI caught my attention this week. I am considering starting a newsletter dedicated to AI in astronomy. What do you think?

Can AI Dream of Unseen Galaxies? Conditional Diffusion Model for Galaxy Morphology Augmentation
This is a commonly discussed problem. How can AI deal with objects outside of its training set? In the case of galaxy morphology, this is a really tough problem and the authors are very brave.

Identifying Anomalous DESI Galaxy Spectra with a Variational Autoencoder
Autoencoders have been used in a number of cases recently. The application to the spectra of the DESI survey is particularly interesting and it may become a fascinating precedent for other projects like 4MOST, WEAVE, or Gaia.

📈📊Astronomy tip of the Week

One of the most used softwares to display astronomical images is called Aladin but today this is not the main topic of the astronomy tip of the week.

Aladin has a lighter version which can be easily implemented on a website to display images. This version is called Aladin Lite

I recommend you to give a look at it and browse between different objects and the different surveys that can be accessed with it.

Once you get used to it, you start recognising that it is used almost everywhere.

Yet another extraordinary achievement of the people of the Strasbourg astronomical Data Center (CDS)

🫣❓What is on the horizon?

Big conferences, big news or big events.

Brazilian Astronomical Society Scientific Meeting, Caxambu (MG), 28 Sep - 2 Oct 2025