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Planets with short orbital periods (roughly under 10 days) are common around stars like the Sun 1 , 2 . Stars expand as they evolve and thus we expect their close planetary companions to be engulfed, possibly powering luminous mass ejections from the host star 3 – 5 . However, this phase has never been directly observed. Here we report observations of ZTF SLRN-2020, a short-lived optical outburst in the Galactic disk accompanied by bright and long-lived infrared emission. The resulting light curve and spectra share striking similarities with those of red novae 6 , 7 —a class of eruptions now confirmed 8 to arise from mergers of binary stars. Its exceptionally low optical luminosity (approximately 10 35  erg s −1 ) and radiated energy (approximately 6.5 × 10 41  erg) point to the engulfment of a planet of fewer than roughly ten Jupiter masses by its Sun-like host star. We estimate the Galactic rate of such subluminous red novae to be roughly between 0.1 and several per year. Future Galactic plane surveys should routinely identify these, showing the demographics of planetary engulfment and the ultimate fate of planets in the inner Solar System. Observations of ZTF SLRN-2020, a short-lived optical outburst in the Galactic disk accompanied by bright, long-lived infrared emission, show that the resulting light curve and spectra are consistent with the signatures of a planet being engulfed by its host star.

The Galactic nova rate is intimately linked to our understanding of its chemical enrichment and progenitor channels of Type Ia supernovae. Yet past estimates have varied by more than an order of magnitude (\\(\\approx10-300\\) yr\\(^{-1}\\)) owing to limitations in both discovery methods as well as assumptions regarding the Galactic dust distribution and extragalactic stellar populations. Recent estimates utilizing synoptic near-infrared surveys have begun to provide a glimpse of a consensus (\\(\\approx25-50\\) yr\\(^{-1}\\)); however, a consistent estimate remains lacking. Here, we present the first all-sky search for Galactic novae using 8 years of data from the NEOWISE mid-infrared (MIR) survey. Operating at \\(3.4\\) and \\(4.6\\) \\(\\mu\\)m where interstellar extinction is negligible, the 6-month cadence NEOWISE dataset offers unique sensitivity to discover slowly evolving novae across the entire Galaxy. Using a novel image subtraction pipeline together with systematic selection criteria, we identify a sample of 49 rapidly evolving MIR outbursts as candidate Galactic novae. While 27 of these sources are known novae, the remaining are previously missed nova candidates discovered in this work. The unknown events are spatially clustered along the densest and most heavily obscured regions of the Galaxy where previous novae are severely underrepresented. We use simulations of the NEOWISE survey strategy, the pipeline detection efficiency, and our criteria to derive a Galactic nova rate of \\(47.9^{+3.1}_{-8.3}\\) yr\\(^{-1}\\). The discovery of these exceptionally bright (yet overlooked) nova candidates confirm emerging suggestions that optical surveys have been highly incomplete in searches for Galactic novae, highlighting the potential for MIR searches in revealing the demographics of Galactic stellar outbursts.

We present the unWISE Catalog, containing the positions and fluxes of roughly two billion objects observed by the Wide-field Infrared Survey Explorer (WISE) over the full sky. The unWISE Catalog has two advantages over the existing WISE catalog (AllWISE): first, it is based on significantly deeper imaging, and second, it features improved modeling of crowded regions. The deeper imaging used in the unWISE Catalog comes from the coaddition of all publicly available 3\\(-\\)5 micron WISE imaging, including that from the ongoing NEOWISE-Reactivation mission, thereby increasing the total exposure time by a factor of 5 relative to AllWISE. At these depths, even at high Galactic latitudes many sources are blended with their neighbors; accordingly, the unWISE analysis simultaneously fits thousands of sources to obtain accurate photometry. Our new catalog detects sources at 5-sigma roughly 0.7 magnitudes fainter than the AllWISE catalog and more accurately models millions of faint sources in the Galactic plane, enabling a wealth of Galactic and extragalactic science. In particular, relative to AllWISE, unWISE doubles the number of galaxies detected between redshifts 0 and 1 and triples the number between redshifts 1 and 2, cataloging more than half a billion galaxies over the whole sky.

While the vast majority of Tidal Disruption Events (TDEs) has been identified by wide-field sky surveys in the optical and X-ray bands, recent studies indicate that a considerable fraction of TDEs may be dust obscured, and thus preferentially detected in the infrared (IR) wavebands. In this Letter, we present the discovery of a luminous mid-IR nuclear flare (termed WTP 14adbjsh) identified in a systematic transient search of archival images from the NEOWISE mid-IR survey. The source reached a peak luminosity of \\(L \\simeq 10^{43} \\text{erg s}^{-1}\\) at 4.6 \\({\\mu}\\)m in 2015, before fading in the IR with a TDE-like \\(F \\propto t^{-5/3}\\) decline, radiating a total of more than \\( 3\\times 10^{51}\\) erg in the last 7 years. The transient event took place in the nearby galaxy NGC 7392, at a distance of around 42 Mpc; yet, no optical or X-ray flare is detected. We interpret the transient as the nearest TDE candidate detected in the last decade, which was missed at other wavelengths due to dust obscuration, hinting at the existence of TDEs that have been historically overlooked. Unlike most previously detected TDEs, the transient was discovered in a star forming galaxy, corroborating earlier suggestions that dust obscuration suppresses significantly the detection of TDEs in these environments. Our results demonstrate that the study of IR-detected TDEs is critical in order to obtain a complete understanding of the physics of TDEs, and to conclude whether TDEs occur preferentially in a particular class of galaxies.

We introduce the Wide-field Retrieval of Astrodata Program (WRAP), a tool created to aid astronomers in gathering photometric and astrometric data for point sources that may confuse simple cross-matching algorithms because of their faintness or motion. WRAP allows astronomers to correctly cross-identify objects with proper motion across multiple surveys by wedding the catalog data with its underlying images, thus providing visual confirmation of cross-associations in real time. Developed within the Backyard Worlds: Planet 9 citizen science project, WRAP aims to aid in the characterization of faint, high motion sources by this collaboration (and others).

We present the discovery of CWISE J151044.74\\(-\\)524923.5, a wide low-mass companion to the nearby (\\(\\sim\\)24.7 pc) system L 262-74, which was identified through the Backyard Worlds: Planet 9 citizen science project. We detail the properties of the system, and we assess that this companion is a mid-L dwarf, which will need to be verified spectroscopically. With an angular separation of 74\\farcs3, we estimate a projected physical separation of \\(\\sim\\)1837 au from the central system.

A new class of white dwarfs, dubbed DAHe, that present Zeeman-split Balmer lines in emission has recently emerged. However, the physical origin of these emission lines remains unclear. We present here a sample of 21 newly identified DAHe systems and determine magnetic field strengths and (for a subset) periods which span the ranges of ~ 6.5 -- 147 MG and ~ 0.4 -- 36 h respectively. All but four of these systems were identified from the Dark Energy Spectroscopic Instrument (DESI) survey sample of more than 47000 white dwarf candidates observed during its first year of observations. We present detailed analysis of the new DAHe WDJ161634.36+541011.51 with a spin period of 95.3 min, which exhibits an anti-correlation between broadband flux and Balmer line strength that is typically observed for this class of systems. All DAHe systems cluster closely on the Gaia Hertzsprung-Russell diagram where they represent ~ 1 per cent of white dwarfs within that region. This grouping further solidifies their unexplained emergence at relatively late cooling times and we discuss this in context of current formation theories. Nine of the new DAHe systems are identifiable from SDSS spectra of white dwarfs that had been previously classified as featureless DC-type systems. We suggest high S/N, unbiased observations of DCs as a possible route for discovering additional DAHe systems.

We detect the cross-correlation between 2.7 million DESI quasar targets across 14,700 deg\\(^2\\) (180 quasars deg\\(^{-2}\\)) and Planck 2018 CMB lensing at \\(\\sim\\)30\\(\\sigma\\). We use the cross-correlation on very large scales to constrain local primordial non-Gaussianity via the scale dependence of quasar bias. The DESI quasar targets lie at an effective redshift of 1.51 and are separated into four imaging regions of varying depth and image quality. We select quasar targets from Legacy Survey DR9 imaging, apply additional flux and photometric redshift cuts to improve the purity and reduce the fraction of unclassified redshifts, and use early DESI spectroscopy of 194,000 quasar targets to determine their redshift distribution and stellar contamination fraction (2.6%). Due to significant excess large-scale power in the quasar autocorrelation, we apply weights to mitigate contamination from imaging systematics such as depth, extinction, and stellar density. We use realistic contaminated mocks to determine the greatest number of systematic modes that we can fit, before we are biased by overfitting and spuriously remove real power. We find that linear regression with one to seven imaging templates removed per region accurately recovers the input cross-power, \\(f_{\\textrm{NL}}\\) and linear bias. As in previous analyses, our \\(f_{\\textrm{NL}}\\) constraint depends on the linear primordial non-Gaussianity bias parameter, \\(b_{\\phi} = 2(b - p)\\delta_c\\) assuming universality of the halo mass function. We measure \\(f_{\\textrm{NL}} = -26^{+45}_{-40}\\) with \\(p=1.6\\) \\((f_{\\textrm{NL}} = -18^{+29}_{-27}\\) with \\(p=1.0\\)), and find that this result is robust under several systematics tests. Future spectroscopic quasar cross-correlations with Planck lensing lensing can tighten the \\(f_{\\textrm{NL}}\\) constraints by a factor of 2 if they can remove the excess power on large scales in the quasar auto power spectrum.

We present the discovery of CWISE J203546.35-493611.0, a peculiar M8 companion to the M4.5 star APMPM J2036-4936 discovered through the citizen science project Backyard Worlds: Planet 9. Given CWISE J203546.35-493611.0's proper motion (\\(\\mu_{\\alpha}\\), \\(\\mu_{\\delta}\\)) = (\\(-\\)126\\(\\pm\\)22, \\(-\\)478\\(\\pm\\)23) and angular separation of 34.2\\(''\\) from APMPM 2036-4936, we calculate a chance alignment probability of \\(1.15 \\times 10^{-6}\\). Both stars in this system appear to be underluminous, and the spectrum obtained for CWISE J203546.35-493611.0 shows a triangular H band. Further study of this system is warranted to understand these peculiarities.

We present findings of the detection of Magnesium II (Mg II, {\\lambda} = 2796, 2803 Å) absorbers from the early data release of the Dark Energy Spectroscopic Instrument (DESI). DESI is projected to obtain spectroscopy of approximately 3 million quasars (QSOs), of which over 99% are anticipated to be at redshifts greater than z > 0.3, such that DESI would be able to observe an associated or intervening Mg II absorber illuminated by the background QSO. We have developed an autonomous supplementary spectral pipeline that detects these systems through an initial line-fitting process and then confirms the line properties using a Markov Chain Monte Carlo sampler. Based upon a visual inspection of the resulting systems, we estimate that this sample has a purity greater than 99%. We have also investigated the completeness of our sample in regard to both the signal-to-noise properties of the input spectra and the rest-frame equivalent width (W0) of the absorber systems. From a parent catalog containing 83,207 quasars, we detect a total of 23,921 Mg II absorption systems following a series of quality cuts. Extrapolating from this occurrence rate of 28.8% implies a catalog at the completion of the five-year DESI survey that will contain over eight hundred thousand Mg II absorbers. The cataloging of these systems will enable significant further research because they carry information regarding circumgalactic medium environments, the distribution of intervening galaxies, and the growth of metallicity across the redshift range 0.3 < z < 2.5.