Related papers: The First Quantitative Study of Tail Regrowth of C…

We observed 34 comets using the 24 micron camera on the Spitzer Space Telescope. Each image contains the nucleus and covers at least 10^6 km of each comet's orbit. Debris trails due to mm-sized or larger particles were found along the…

Understanding the evolution of radial sizes and instantaneous expansion speeds of coronal mass ejections (CMEs) is crucial for assessing their impact duration on Earth's environment. We introduce a non-conventional approach to derive the…

We present the first results of a photometric survey of poorly studied nova remnants in the Northern Hemisphere. The main results are as follows: DM Gem shows a modulation at 0.123 d (probably linked to the orbit) and rapid variations at…

Context. We study two coronal mass ejections (CMEs) observed between April 1-2, 2019 by both the inner Wide-Field Imager for Parker Solar Probe (WISPR-I) and the inner heliospheric imager (HI-1) on board STEREO-A. This is the first study of…

We examine the rise and sudden demise of comet C/2010 X1 (Elenin) on its approach to perihelion. Discovered inbound at 4.2 AU, this long-period comet was predicted to become very bright when near perihelion, at 0.48 AU on 2011 September 10.…

Interstellar objects provide a direct window into the environmental conditions around stars other than the Sun. The recent discovery of 3I/ATLAS, a new interstellar comet, offers a unique opportunity to investigate the physical and chemical…

We report on photometry and imaging of Comet 10P/Tempel 2 obtained at Lowell Observatory from 1983 through 2011. We measured a nucleus rotation period of 8.950 +/- 0.002 hr from 2010 September to 2011 January. This rotation period is longer…

We have used the unique far-UV imaging capability offered by a sounding rocket borne instrument to acquire observations of C/2012 S1 (ISON) when its angular separation with respect to the sun was 26.3deg, on 2013 November 20.49. At the time…

The first severe (G4) geomagnetic storm of Solar Cycle 25 occurred on 23-24 April 2023, following the arrival of a Coronal Mass Ejection (CME) on 23 April. The characteristics of this CME, measured from coronagraphs (speed and mass), did…

Forecasting the geomagnetic effects of solar coronal mass ejections (CMEs) is currently an unsolved problem. CMEs, responsible for the largest values of the north-south component of the interplanetary magnetic field, are the key driver of…

The recovery of cosmic ray He nuclei of energy ~150-250 MeV/nuc in solar cycle #23 from 2004 to 2010 has been followed at the Earth using IMP and ACE data and at V2 between 74-92 AU and also at V1 beyond the heliospheric termination shock…

Our study attempts to understand the collision characteristics of two coronal mass ejections (CMEs) launched successively from the Sun on 2013 October 25. The estimated kinematics, from three-dimensional (3D) reconstruction techniques…

The Solar TErrestrial RElations Observatory (STEREO) provides high cadence and high resolution images of the structure and morphology of coronal mass ejections (CMEs) in the inner heliosphere. CME directions and propagation speeds have…

Interstellar objects (ISOs), particularly those with cometary activity, provide unique insight into the primordial physical and chemical conditions present during the formation of the planetary system in which they originated. Observations…

Interplanetary space is characteristically structured mainly by high-speed solar wind streams emanating from coronal holes and transient disturbances such as coronal mass ejections (CMEs). While high-speed solar wind streams pose a…

We observed comet C/2025 A6 with the Five-hundred-meter Aperture Spherical radio Telescope (FAST) equipped with the ultra-wideband receiver from 2025 October 23 to November 8, and it was the first detection for this comet with FAST.Through…

Follow-up imaging observations of the first detected interstellar comet 2I/Borisov are presented, which were carried out with the Schmidt-Teleskop-Kamera at the University Observatory Jena in 11 observing epochs in October and November…

During its sungrazing perihelion passage, comet ISON appeared in the field of view of the SUMER spectrometer and allowed unique observations at far-ultraviolet wavelengths with high spatial and temporal resolution. We report results of…

The recovery of cosmic ray protons of energy ~150-250 MeV/nuc in solar cycle #23 from 2004 to 2010 has been followed at the Earth using IMP, ACE and balloon data and also at V2 between 74-92 AU and at V1 beyond the heliospheric termination…

Long-period comet C/2018 F4 (PANSTARRS) was observed to show duplicity of its inner region in 2020 September, suggestive of a splitting event. We here present analyses of our observations of the comet taken from the LOOK project and the…