NLTT 51469(AB)b : géante froide en orbite circumbinaire, prise dans la danse gravitationnelle de deux étoiles. Chaos stable façon Tatooine NASA arxiv.org/abs/1905.01217 #Space #Science #Astrophysics #Exoplanets #BinaryStars #TatooineVibes

A low-mass triple system with ...
A low-mass triple system with a wide L/T transition brown dwarf component: NLTT 51469AB/SDSS 2131-0119

We demonstrate that the previously identified L/T transition brown dwarf SDSS J213154.43-011939.3 (SDSS 2131-0119) is a widely separated (82.3'', $\sim$3830 au) common proper motion companion to the low-mass star NLTT 51469, which we reveal to be a close binary itself, separated by 0.64''$\pm$0.01'' ($\sim$30 au). We find the proper motion of SDSS 2131-0119 of $μ_α\cosδ=-100\pm20$, $μ_δ=-230\pm20$ mas/yr consistent with the proper motion of the primary provided by Gaia DR2: $μ_α\cosδ=-95.49\pm0.96$, $μ_δ=-239.38\pm0.96$ mas/yr. Based on optical and near-infrared spectroscopy we classify NLTT 51469A as a M3$\pm$1 dwarf, estimate photometrically the spectral type of its close companion NLTT 51469B at $\sim$M6 and confirm the spectral type of the brown dwarf to be L9$\pm$1. Using radial velocity, proper motion and parallax we derived the $UVW$ space velocities of NLTT 51469A, showing that the system does not belong to any known young stellar moving group. The high $V, W$ velocities, lack of 670.8 nm Li I absorption line, and absence of H$α$ emission, detected X-rays or UV excess, indicate that the system is likely a member of the thin disk population and is older than 1 Gyr. For the parallactic distance of $46.6\pm1.6$ pc from Gaia DR2 we determined luminosities of $-1.50^{+0.02}_{-0.04}$ and $-4.4\pm0.1$ dex of the M3 and L9, respectively. Considering the spectrophotometric estimation which yields a slightly lower distance of $34^{+10}_{-13}$ pc the obtained luminosities are $-1.78^{+0.02}_{-0.04}$ and $-4.7^{+0.3}_{-0.5}$ dex. We also estimated their effective temperatures and masses, and obtained 3410$^{+140}_{-210}$ K and $0.42\pm0.02 M_{\odot}$ for the primary, and 1400-1650 K and $0.05-0.07 M_{\odot}$ for the wide companion. For the $\sim$M6 component we estimated $T_{eff}=2850\pm200 K$ and $m=0.10^{+0.06}_{-0.01} M_{\odot}$.

arXiv.org
NLTT 51469(AB)b : géante froide en orbite circumbinaire, prise dans la danse gravitationnelle de deux étoiles. Chaos stable façon Tatooine NASA https://arxiv.org/abs/1905.01217 #Space #Science #Astrophysics #Exoplanets #BinaryStars #TatooineVibes
A low-mass triple system with a wide L/T transition brown dwarf component: NLTT 51469AB/SDSS 2131-0119

We demonstrate that the previously identified L/T transition brown dwarf SDSS J213154.43-011939.3 (SDSS 2131-0119) is a widely separated (82.3'', $\sim$3830 au) common proper motion companion to the low-mass star NLTT 51469, which we reveal to be a close binary itself, separated by 0.64''$\pm$0.01'' ($\sim$30 au). We find the proper motion of SDSS 2131-0119 of $μ_α\cosδ=-100\pm20$, $μ_δ=-230\pm20$ mas/yr consistent with the proper motion of the primary provided by Gaia DR2: $μ_α\cosδ=-95.49\pm0.96$, $μ_δ=-239.38\pm0.96$ mas/yr. Based on optical and near-infrared spectroscopy we classify NLTT 51469A as a M3$\pm$1 dwarf, estimate photometrically the spectral type of its close companion NLTT 51469B at $\sim$M6 and confirm the spectral type of the brown dwarf to be L9$\pm$1. Using radial velocity, proper motion and parallax we derived the $UVW$ space velocities of NLTT 51469A, showing that the system does not belong to any known young stellar moving group. The high $V, W$ velocities, lack of 670.8 nm Li I absorption line, and absence of H$α$ emission, detected X-rays or UV excess, indicate that the system is likely a member of the thin disk population and is older than 1 Gyr. For the parallactic distance of $46.6\pm1.6$ pc from Gaia DR2 we determined luminosities of $-1.50^{+0.02}_{-0.04}$ and $-4.4\pm0.1$ dex of the M3 and L9, respectively. Considering the spectrophotometric estimation which yields a slightly lower distance of $34^{+10}_{-13}$ pc the obtained luminosities are $-1.78^{+0.02}_{-0.04}$ and $-4.7^{+0.3}_{-0.5}$ dex. We also estimated their effective temperatures and masses, and obtained 3410$^{+140}_{-210}$ K and $0.42\pm0.02 M_{\odot}$ for the primary, and 1400-1650 K and $0.05-0.07 M_{\odot}$ for the wide companion. For the $\sim$M6 component we estimated $T_{eff}=2850\pm200 K$ and $m=0.10^{+0.06}_{-0.01} M_{\odot}$.

arXiv.org

Einstein’s Relativity May Explain the Scarcity of Planets Orbiting Binary Star Systems

📰 Original title: Why two-sun planets keep disappearing scientists blame Einstein

🤖 IA: It's not clickbait ✅
👥 Usuarios: It's not clickbait ✅

View full AI summary: https://killbait.com/en/einsteins-relativity-may-explain-the-scarcity-of-planets-orbiting-binary-star-systems/?redirpost=b7abd2b2-f02e-475b-aba9-61edecc9ca39

#astronomy #exoplanets #relativity #binarystars

Einstein’s Relativity May Explain the Scarcity of Planets Orbiting Binary Star Systems

Astronomers have long been puzzled by the surprising scarcity of planets that orbit two stars, known as circumbinary planets—similar to the fictional world of Tatooine in Star Wars.

KillBait Archive

Einstein’s Relativity May Explain the Scarcity of Planets Orbiting Binary Star Systems

📰 Original title: Why two-sun planets keep disappearing scientists blame Einstein

🤖 IA: It's not clickbait ✅
👥 Usuarios: It's not clickbait ✅

View full AI summary: https://killbait.com/en/einsteins-relativity-may-explain-the-scarcity-of-planets-orbiting-binary-star-systems/?redirpost=b7abd2b2-f02e-475b-aba9-61edecc9ca39

#astronomy #exoplanets #relativity #binarystars

Einstein’s Relativity May Explain the Scarcity of Planets Orbiting Binary Star Systems

Astronomers have long been puzzled by the surprising scarcity of planets that orbit two stars, known as circumbinary planets—similar to the fictional world of Tatooine in Star Wars.

KillBait Archive
Mystère résolu pour Gamma Cassiopeiae : ses émissions X extrêmes viendraient d’un compagnon naine blanche aspirant la matière de l’étoile www.techno-science.net/actualite/my... #Space #Science #Innovation #Astrophysics #Cosmology #GammaCassiopeiae #XrayAstronomy #BinaryStars

🌟 Le mystère des émissions de ...
🌟 Le mystère des émissions de l'étoile Gamma-Cassiopeiae résolu

Depuis plus d'un siècle, l'étoile nommée Gamma-Cassiopeiae (ou "Gamma-Cas") perturbe les astronomes. Visible à...

Techno-Science.net
Mystère résolu pour Gamma Cassiopeiae : ses émissions X extrêmes viendraient d’un compagnon naine blanche aspirant la matière de l’étoile
https://www.techno-science.net/actualite/mystere-emissions-etoile-gamma-cassiopeiae-resolu-N28577.html #Space #Science #Innovation #Astrophysics #Cosmology #GammaCassiopeiae #XrayAstronomy #BinaryStars
🌟 Le mystère des émissions de l'étoile Gamma-Cassiopeiae résolu

Depuis plus d'un siècle, l'étoile nommée Gamma-Cassiopeiae (ou "Gamma-Cas") perturbe les astronomes. Visible à...

Techno-Science.net

Weekly Update from the Open Journal of Astrophysics – 18/04/2026

It is Saturday morning, and therefore time for yet another update of activity at the Open Journal of Astrophysics. Since the last update we have published a further six papers, bringing the number in Volume 9 (2026) to 82 and the total so far published by OJAp up to 530.

I will continue to include the posts made on our Mastodon account (on Fediscience) to encourage you to visit it. Mastodon is a really excellent service, and a more than adequate replacement for X/Twitter (which nobody should be using); these announcements also show the DOI for each paper.

The first paper to report this week is “Beyond Spherical geometry: Unraveling complex features of objects orbiting around stars from its transit light curve using deep learning” by Ushasi Bhowmick & Shivam Kumaran (Indian Space Research Institute, Ahmedabad, India). This study uses deep neural networks to predict the shape of objects orbiting stars based on their transit light curves, demonstrating the potential to extract geometric information from these systems. It was published on Monday 13th April in the folder Earth and Planetary Astrophysics and the overlay can be seen here:

You can find the officially accepted version on arXiv here and the announcement on Fediverse here:

https://fediscience.org/@OJ_Astro/116395992732332356

The second paper for this week, also published on Monday 13th April but in the folder Astrophysics of Galaxies, is “statmorph-lsst: Quantifying and correcting morphological biases in galaxy surveys” by Elizaveta Sazonova (U. Waterloo, Canada) and an international cast of 18 others. This paper presents an investigation of potential biases in quantitative morphology metrics used in galaxy evolution studies, proposing two new measurements to resolve biases, and provides a related Python package (statmorph-lsst), which can be found here on github.

The overlay for this one is here:

The official version of the paper can be found on arXiv here and the Fediverse announcement here:

https://fediscience.org/@OJ_Astro/116396069424189312

Next one up, the third paper of the week, one of four published on Friday 17th April, is “Disentangling the galactic and intergalactic components in 313 observed Lyman-alpha line profiles between redshift 0 and 5” by Siddhartha Gurung-López (Universitat de València, Spain) and 7 others based in Spain and Germany. Published in the folder Astrophysics of Galaxies, this paper uses the zELDA package to analyze Lyman-alpha photons from star-forming galaxies, revealing IGM effects dominate Lyman-alpha observability at high redshifts, while galactic outflows become more important at lower z.

The overlay for this one is here:

The final, accepted version can be found on arXiv here and the Mastodon announcement is here:

https://fediscience.org/@OJ_Astro/116418831864134501

The fourth paper this week, also published on Friday 17th April is “Using Symbolic Regression to Emulate the Radial Fourier Transform of the Sérsic Profile for Fast, Accurate and Differentiable Galaxy Profile Fitting” by Tim B. Miller (Northwestern University, USA) and Imad Pasha (Yale University, USA). This one is published in the folder Instrumentation and Methods for Astrophysics: it develops an emulator for galaxy profile fitting in Fourier space, improving speed by 2.5 times with minimal accuracy loss, aiding in managing increasing data flow.

The overlay is here:

The finally accepted version of this paper can be found here and the Mastodon announcement follows:

https://fediscience.org/@OJ_Astro/116418855010158656

The fifth paper for this week is “The THESAN project: Lyman-alpha emitters as probes of ionized bubble sizes” by Meredith Neyer (MIT, USA) and 6 others based in the USA, Colombia, Canada, Japan and UK. The study uses THESAN simulations to explore how Lyman-alpha emitters (LAEs) trace ionized bubble sizes during the Epoch of Reionization, providing a framework for interpreting LAE surveys. This was published on Friday 17th April in the folder Astrophysics of Galaxies.

The overlay for this one is here:

You can find the authorized version of this paper on arXiv here and the Fediverse announcement is here:

https://fediscience.org/@OJ_Astro/116418887225003954

The sixth and final paper for this week is “Closed-Form Statistical Relations Between Projected Separation, Semimajor Axis, Companion Mass, and Host Acceleration” by Timothy D Brandt (Space Telescope Science Institute, USA). This was published on Friday 17th April in the folder Solar and Stellar Astrophysics. In this paper the author derives statistical relationships between radial velocity, a companion’s mass, and projected separation, useful for calculations requiring derivatives. The results are verified with empirical comparisons to existing literature.

The overlay for this one is here:

You can find the officially-accepted version on arXiv here and the Mastodon announcement here:

https://fediscience.org/@OJ_Astro/116418938017199814

And that concludes this week’s update. I’ll do another one at the end of next week.

P.S. Just a reminder, for those of you into LinkedIn, that we now have a page there.

#arXiv250303824v4 #arXiv250820266v2 #arXiv250914875v2 #arXiv251018946v2 #arXiv251109644v2 #arXiv260114688v2 #AstrophysicsOfGalaxies #binaryStars #ComputationalAstrophysics #CosmologyAndNonGalacticAstrophysics #DiamondOpenAccess #DiamondOpenAccessPublishing #EarthAndPlanetaryAstrophysics #EpochOfReionization #galaxyFormation #GalaxyMorphology #galaxyProfiles #InstrumentationAndMethodsForAstrophysics #IntergalacticMedium #Ionization #LAEs #lightCurves #LSST #LymanAlphaEmitters #OpenAccess #OpenAccessPublishing #Orbits #SérsicProfile #SolarAndStellarAstrophysics #statmorphLsst #stellarHalos #strongGravitationalLensing #THESAN #zELDA
🎩✨ Oh, the riveting world of boolean options! It's like discovering the vast universe inside a binary star 🌌—spoiler alert: it's just two. Meanwhile, the article meanders like a lost tourist in a tech museum, leaving you #pondering if it too is merely an "experimental" concept. 🤔
https://herecomesthemoon.net/2025/11/how-many-options-fit-into-a-boolean/ #booleanoptions #techmuseum #binarystars #experimentalconcept #HackerNews #ngated
How many options fit into a boolean?

Funny notes on niche optimizations in Rust, and a few updates.

MOND←TECH MAGAZINE
Pour la première fois, une planète est observée orbitant deux étoiles : un vrai bijou pour l’astronomie et nos rêves cosmiques.
https://m.techno-science.net/actualite/premiere-image-directe-planete-aussi-proche-etoiles-doubles-N28311.html
#Space #Science #Innovation #Astrophysics #Exoplanet #BinaryStars #JWSTData #PlanetDiscovery #CosmicFrontier
🪐 Première image directe d'une planète aussi proche d'étoiles doubles

Une équipe de recherche internationale annonce la découverte d'une nouvelle exoplanète en orbite autour d'un...

Techno-Science.net
NASA Hubble Helps Detect ‘Wake’ of Betelgeuse’s Elusive Companion Star http://dlvr.it/TQ9hgM #Astrophysics #AstrophysicsDivision #BinaryStars