Secular brightness curves of 272 comets

Abstract

We investigate the brightening behavior of long-period comets as a function of dynamical age, defined by the original reciprocal semimajor axis, $1/a_0$. Our goal is to test long-standing claims about comet behavior using a large number of available measurements. We use a large set of photometric observations to compute and analyze global and local brightening curves for 272 long-period comets. Observed magnitudes are fitted with a linear model in log heliocentric distance, from which we derive brightening parameters for each comet. We categorize the sample into dynamically new, intermediate, and old comets, comparing their brightening behavior. We also examine the relationships between dynamical age and other orbital and physical parameters. Dynamically new comets are seen to brighten more slowly than old comets, particularly within 3 au from the Sun. The brightening rate of new comets appears to vary with heliocentric distance. New comets are intrinsically brighter than old comets, and exhibit a tighter correlation between brightening parameters.

Accepted for publication in A&A on March 24, 2025. 18 pages, 17 figures. Data at https://doi.org/10.5281/zenodo.15100031

References in corpus (15)

• LSST: from Science Drivers to Reference Design and Anticipated Data Products
• Preliminary Results from NEOWISE: An Enhancement to the Wide-field Infrared Survey Explorer for Solar System Science
• astroquery: An Astronomical Web-Querying Package in Python
• Design and operation of the ATLAS Transient Science Server
• The Demographics of Long-Period Comets
• Reassessing the Source of Long-Period Comets
• Distant Comet C/2017 K2 and the Cohesion Bottleneck
• Cometary Activity Begins at Kuiper Belt Distances: Evidence from C/2017 K2
• Discovery of Carbon Monoxide in Distant Comet C/2017 K2 (PANSTARRS)
• Destruction of Long-Period Comets
• Activity of 50 Long-Period Comets Beyond 5.2 AU
• Trajectory of the stellar flyby that shaped the outer solar system
• Are there any pristine comets? Constraints from pebble structure
• The Catalogue of Cometary Orbits and their Dynamical Evolution
• A link between the size and composition of comets

Cited by in corpus (1)

• Dynamically New Comet C/2025 D1 (Groeller) with Record Perihelion Distance