raptop (π’€― π’„· π’„ˆπ’€­π’‡)

@Newpa_Hasai
115 Followers
155 Following
12.8K Posts

Astronomy diapsid and number cruncher, other skills as required. Primary focus is exoplanets, but relatively up on other aspects of space/astronomy/spaceflight. Not indebted to π’€­π’Œ“. Trying not to be just a stabby bird lost in the Outer Dark (p ≀ 0.05).

'blog is about what you'd expect (pdn4kd.github.io)

(Also on esper and libera IRC servers)

π“…ƒnihilopteryx, π’€­π’‰Žπ’ˆͺπ’„·, and/or shantak
Professional Nounshe/him (p-value == ???)
Amateur Nounsthey/them
githubhttps://github.com/pdn4kd/
raptop (π’€― π’„· π’„ˆπ’€­π’‡)1d ago
mcc1d ago
On June 4, 2027, every verb tense on Wikipedia will be changed from "is" to "was" in a rapid flurry of edits. No one will understand why this happened for about six hours
raptop (π’€― π’„· π’„ˆπ’€­π’‡)2d ago
Okay, the Rubin Observatory Data Preview 1 has been out for a while. But this paper describing it is new: https://arxiv.org/abs/2603.23786
The Vera C. Rubin Observatory Data Preview 1

We present Rubin Data Preview 1 DP1, the first data from the NSF DOE Vera C Rubin Observatory, comprising raw and calibrated single epoch images, coadds, difference images, detection catalogs, and ancillary data products. DP1 is based on 1792 optical near infrared exposures acquired over 48 distinct nights by the Rubin Commissioning Camera LSSTComCam on the Simonyi Survey Telescope at the Summit Facility on Cerro PachΓ³n Chile in late 2024. DP1 covers $\sim$15 deg$^2$ distributed across seven roughly equal-sized non-contiguous fields, each independently observed in six broad photometric bands $ugrizy$. The median FWHM of the point spread function across all bands is approximately 1.14 arcseconds, with the sharpest images reaching about 0.58 arcseconds. The 5$Οƒ$ point source depths for coadded images in the deepest field the Extended Chandra Deep Field South are $u$ = 24.55, $g$ = 26.18, $r$ = 25.96, $i$ = 25.71, $z$ = 25.07, $y$ = 23.1. Other fields are no more than 2.2 magnitudes shallower in any band where they have nonzero coverage. DP1 contains approximately 2.3 million distinct astrophysical objects, of which 1.6 million are extended in at least one band in coadds and 431 solar system objects of which 93 are new discoveries. DP1 is approximately 3.5 TB in size and is available to Rubin data rights holders via the Rubin Science Platform a cloud based environment for the analysis of petascale astronomical data. While small compared to future LSST releases its high quality and diversity of data support a broad range of early science investigations ahead of full operations in 2026.

arXiv.org
Show threadraptop (π’€― π’„· π’„ˆπ’€­π’‡)2d ago

And a day later, another way of slicing the Kepler Data shows that generally systems with more planets have lower eccentricities, and gives a scale of how many non-transiting planets we're missing in ones where we're finding one or more planets. But also that a lot of 'fancier' architectures that have been proposed are uncommon.

https://arxiv.org/abs/2603.23644

No strong associations between eccentricity and orbital architecture in Kepler compact multis

The dynamical history of a planetary system is recorded in the present day architecture of its constituent planets' sizes, orbital periods, and eccentricities. Studying the relationships between these quantities for large populations provides a window into the processes by which planetary systems form and evolve. Recently, Gilbert, Petigura, and Entrican (2025) performed a hierarchical Bayesian analysis of 1626 planets from the Kepler census, demonstrating a strong relationship between planet radius $R_p$ and orbital eccentricity $e$. Here, we build upon that work to search for correlations between eccentricity and system architecture, focusing on compact systems of small planets. We find that small planets on short orbits ($P < 4$ days) show evidence of tidal circularization. This trend is well established for Jovian planets but a novel finding for super-Earths and sub-Neptunes. We reproduce the known wherein trend single-transiting systems possess elevated eccentricities relative to their multi-transiting counterparts. We further show that systems with two transiting planets have higher eccentricities than those with three or more transiting planets. When compared to population synthesis models, these multiplicity-eccentricity relationships imply that Kepler singles have intrinsic multiplicity ${\sim}3$ and Kepler multis have intrinsic multiplicity ${\sim}4{-}6$. We detect no statistically significant associations between eccentricity and planetary period ratios, gap complexity, size inequality, or size ordering. We interpret these findings as evidence either in favor of a quiescent formation history or against dynamical processes which excite eccentricity but not inclination. Sub-significant relationships between eccentricity and architecture imply that subtle, multi-factor trends may be detectable in the future using more sophisticated statistical techniques.

arXiv.org
Show threadraptop (π’€― π’„· π’„ˆπ’€­π’‡)2d ago
Why this? Well, the range for close-in giant planets is known okay, but it’s not yet well-measured for smaller ones. TESS planets are being used in part because of how distant/faint Kepler stars are, though given the systems I suspect that this overlaps with doing RV follow-ups to confirm and get the masses of TOIs. Within the initial results, the system with two confirmed planets seems to have a small misalignment, while the rest are aligned.
raptop (π’€― π’„· π’„ˆπ’€­π’‡)2d ago

Today in #exoplanets on arχiv: https://arxiv.org/abs/2603.23713

A survey using Keck of 4 TESS systems (so far, they’ll do more) and using the Rossiter-McLaughlin effect to determine spin-orbit alignment. Specifically they’re looking for compact systems (the planet orbits are sort of like those of the moons of ♃ or β™…) with relatively small (Earth to sub-Saturn) planets, and if the orbital inclinations are in the same direction as the star’s rotation.

The KPF-SLOPE Survey - Small, Compact Multi-Planet Systems Appear Spin-Orbit Aligned

The angle between stellar spin axes and planetary orbits -- stellar obliquity -- probes the dynamics of planetary migration and evolution. The obliquities of giant planets have been extensively studied because they are the most easily measured. Smaller planets, while more difficult to measure, have the advantage of better reflecting the dynamics of planetary systems because they trigger negligible back-reactions onto the host star. This paper introduces a new observational campaign called the Small, Low-mass Oblique Planets Experiment (SLOPE) survey with the Keck Planet Finder (KPF) spectrograph, and presents four new obliquity measurements. The SLOPE survey focuses on planets smaller than Saturn across a variety of system architectures. The sky-projected obliquities of the four planets measured -- TOI-1386b, TOI-480b, TOI-4596b, and TOI-1823b -- are all consistent with spin-orbit alignment. We validate the planetary nature of TOI-4596b with a significant obliquity detection. Including these measurements, we conducted a statistical analysis of the obliquities of sub-Saturn size planets in different planetary system architectures. Compared to other architectures, those in compact multi-planet systems reside in orbits that appear preferentially aligned with the stellar equator with 6 sigma confidence.

arXiv.org
raptop (π’€― π’„· π’„ˆπ’€­π’‡)2d ago
Lavali ArtFeb 8

Guess I shoulda been drawing owls today.. ah well

Stoats!!

#stoat #stoats #ermine #ermines #weasel #mustelidae #mustelids

They are so shaped <3

raptop (π’€― π’„· π’„ˆπ’€­π’‡)2d ago
Justified Ancient of Moomin3d ago
I would absolutely buy this
raptop (π’€― π’„· π’„ˆπ’€­π’‡)3d ago
it's pronounced 'yagoda'3d ago
Evening doodlin
Show threadraptop (π’€― π’„· π’„ˆπ’€­π’‡)3d ago
Oh, and πŸ”ͺ πŸ”ͺ πŸ”ͺ the popular articles calling this "AI detects 100 TESS planets"
Show threadraptop (π’€― π’„· π’„ˆπ’€­π’‡)3d ago
Finally, hot Jupiter formation (well, okay also warm and cold Jupiters as well) is becoming understood, including the orbital inclination and eccentricity distributions of the various populations. So it’s mostly planet-planet scattering (with warm Jupiters mostly forming in place but getting perturbed orbits?). There are a lot of other details of the population features that won’t fit in a toot: https://arxiv.org/abs/2603.22409 https://arxiv.org/abs/2603.22426
Unified Formation Channel of Hot and Warm Jupiters via Planet-Planet Scattering

Recent observations show distinct orbital architectures for hot and warm Jupiters: hot Jupiters span a wide range of stellar obliquities and tend to host distant companions without close-by companions, whereas warm Jupiters are often aligned and accompanied by both close-by and distant companions. In this paper, we revisit planet-planet scattering and demonstrate that it provides a unified framework for both populations. Using N-body simulations with tides, we explore three regimes: hot (a_1 < 0.1 AU), warm (0.1 < a_1 < 1 AU), and cold (1 < a_1 < 10 AU) scattering. Hot scattering predominantly produces compact hot-Jupiter pairs, which are rarely observed, implying this channel is rare. Cold scattering readily produces retrograde hot Jupiters and likely constitutes a main reservoir feeding the hot-Jupiter population. However, cold scattering produces few inner warm Jupiters at a at about 0.1-0.3 AU. We show that warm scattering naturally fills this gap: high-inclination inner warm Jupiters produced by warm scattering are preferentially removed through further eccentricity excitation followed by tidal circularization into hot Jupiters. As a result, the surviving inner warm Jupiters are biased toward a broad range of eccentricities but modest inclinations, producing the observed "eccentric-but-aligned" population. This story makes testable predictions: (i) warm Jupiters, especially at a >~ 0.3 AU, should not be exclusively aligned, and (ii) warm Jupiters should often host nearby companions with non-negligible mutual inclinations up to <~ 30 degrees.

arXiv.org