Activity of the first interstellar comet 2I/Borisov around perihelion: results from Indian observatories

Aravind, K.; Ganesh, Shashikiran; Venkataramani, Kumar; Sahu, D. K.; Angchuk, Dorje; Unni, Athira

doi:10.1093/mnras/stab084

Cited by 16 publications

(14 citation statements)

References 45 publications

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“…Table A.1 summarises our detections and non-detections. In addition to the NH, CN, C 2 , and NH 2 emission bands, the 630 nm [OI] line, and neutral nickel emission lines that were detected in previous observations (Fitzsimmons et al 2019;Bannister et al 2020;Aravind et al 2021;Kareta et al 2020;McKay et al 2020;Guzik & Drahus 2021), we report the detection of a CH emission band, 557.7 and 636.4 nm forbidden oxygen lines, as well as emission lines from FeI. Our detection of NH, CH, FeI, and NiI emissions are illustrated in Figures A.1, A.2, and A.3, respectively.…”

Section: Appendix A: Detected Speciesmentioning

confidence: 81%

“…Early observations, mainly with optical low-resolution spectrographs, showed that 2I is depleted in C 2 , similarly to So-E-mail: copi@roe.ac.uk lar System carbon-chain depleted comets (Fitzsimmons et al (2019); Opitom et al (2019a); Bannister et al (2020); Kareta et al (2020); Lin et al (2020); Aravind et al (2021)). Later, Cordiner et al (2020) and Bodewits et al (2020) reported that 2I is very rich in CO relative to both water and HCN, more than any Solar System comet observed within 2.5 au from the Sun.…”

Section: Introductionmentioning

confidence: 77%

“…This provided the first indication that the composition of the first active interstellar comet might differ from that of most Solar System comets. Recent results indicated changes in the mixing ratio of species in the coma of 2I between pre-and post-perihelion observations, hinting at a heterogeneous nucleus (Xing et al 2020;Yang et al 2021;Aravind et al 2021).…”

Section: Introductionmentioning

confidence: 99%

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The similarity of the interstellar comet 2I/Borisov to Solar System comets from high-resolution optical spectroscopy

Opitom

Jehin

Hutsemékers

et al. 2021

A&A

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Aims. 2I/Borisov (hereafter 2I) is the first visibly active interstellar comet observed in the Solar System, allowing us for the first time to sample the composition of a building block from another system. We report on the monitoring of 2I with the Ultraviolet-Visual Echelle Spectrograph (UVES), the high-resolution optical spectrograph of the ESO Very Large Telescope at Paranal, for four months from November 15, 2019 to March 16, 2020. Our goal is to characterise the activity and composition of 2I with respect to Solar System comets. Methods. We collected high-resolution spectra at 12 different epochs from 2.1 au pre-perihelion to 2.6 au post-perihelion. Results. On December 24 and 26, 2019, close to perihelion, we detected several OH lines of the 309 nm (0-0) band and derived a water production rate of 2.2 ± 0.2 × 10 26 molecules/s. The three [OI] forbidden oxygen lines were detected at different epochs and we derived a green-to-red doublet intensity ratio (G/R) of 0.31±0.05 close to perihelion. The NH 2 ortho and para lines from various bands were measured and allowed us to derive an ortho-to-para abundance ratio (OPR) of 3.21 ± 0.15, corresponding to an OPR and spin temperature of ammonia of 1.11 ± 0.08 and 31 +10 −5 K, respectively. These values are consistent with the values usually measured for Solar System comets. Emission lines of the radicals NH (336 nm), CN (388 nm), CH (431 nm), and C 2 (517 nm) were also detected. Several FeI and NiI lines were identified and their intensities were measured to provide a ratio of log (NiI/FeI) = 0.21 ± 0.18, which is in agreement with the value recently found in Solar System comets. Conclusions. Our high spectral resolution observations of 2I/Borisov and the associated measurements of the NH 2 OPR and the Ni/Fe abundance ratio are remarkably similar to Solar System comets. Only the G/R ratio is unusually high, but it is consistent with the high abundance ratio of CO/H 2 O found by other investigators.

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Section: Appendix A: Detected Speciesmentioning

confidence: 81%

Section: Introductionmentioning

confidence: 77%

Section: Introductionmentioning

confidence: 99%

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The similarity of the interstellar comet 2I/Borisov to Solar System comets from high-resolution optical spectroscopy

Opitom

Jehin

Hutsemékers

et al. 2021

A&A

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show abstract

“…In stark contrast to 'Oumuamua, the interstellar comet Borisov displayed physical characteristics that are broadly consistent with the census of cometary bodies in the Solar System. It had dusty cometary activity (Jewitt & Luu 2019;Bolin et al 2020b;Fitzsimmons et al 2019;Ye et al 2020;McKay et al 2020;Guzik et al 2020;Hui et al 2020;Kim et al 2020;Cremonese et al 2020;Yang et al 2021), and early observations confirmed the presence of carbon and nitrogen based species in the outflow (Opitom et al 2019;Kareta et al 2020;Lin et al 2020;Bannister et al 2020;Xing et al 2020;Aravind et al 2021). It was particularly enriched in CO (Bodewits et al 2020;Cordiner et al 2020), which could be explained if it formed in the outer regions of a protoplanetary disk (Price et al 2021).…”

Section: Introductionmentioning

confidence: 98%

The Population of Interstellar Objects Detectable with the LSST and Accessible for $\textit{In Situ}$ Rendezvous with Various Mission Designs

Hoover¹,

Seligman²,

Payne³

2021

Preprint

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The recently discovered population of interstellar objects presents us with the opportunity to characterize material from extrasolar planetary and stellar systems up close. The forthcoming Rubin Observatory Legacy Survey of Space and Time (LSST) will provide an unprecedented increase in sensitivity to these objects compared to the capabilities of currently operational observational facilities. In this paper, we generate a synthetic population of interstellar objects drawn from their galactic kinematics, and identify the distribution of impact parameters, eccentricities, hyperbolic velocities and sky locations of objects detectable with the LSST. This population is characterized by a clustering of trajectories in the direction of the solar apex and anti-apex, centered at orbital inclinations of ∼ 90 • . We identify the ecliptic or solar apex as the optimal sky locations to search for future interstellar objects as a function of survey limiting magnitude. Moreover, we identify the trajectories of detectable objects that will be reachable for in-situ rendezvous with a dedicated mission with the capabilities of the forthcoming Comet Interceptor or proposed BRIDGE concept. By scaling our fractional population statistics with the inferred spatial number density, we estimate that the LSST will detect of order ∼ 50 interstellar objects over the course of its ∼ 10 year observational campaign. Furthermore, we find that there should be of order ∼ 10 and ∼ 0.05 reachable targets for missions with propulsion capabilities comparable to BRIDGE and Comet Interceptor, respectively. These number estimates will be readily updateable when the number density and size frequency distribution of interstellar objects is better constrained.

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“…Early observations, mainly with optical low-resolution spectrographs, showed that 2I is depleted in C 2 , similarly to solar sys-E-mail: copi@roe.ac.uk tem carbon-chain depleted comets (Fitzsimmons et al (2019); Opitom et al (2019a); Bannister et al (2020); Kareta et al (2020); Lin et al (2020); Aravind et al (2021)). Later, Cordiner et al (2020) and Bodewits et al (2020) reported that 2I is very rich in CO relative to both water and HCN, more than any solar system comet observed within 2.5 au from the Sun.…”

Section: Introductionmentioning

confidence: 99%

The similarity of the interstellar comet 2I/Borisov to solar system comets from high resolution optical spectroscopy

Opitom,

Jehin,

Hutsemékers

et al. 2021

Preprint

View full text Add to dashboard Cite

Aims. 2I/Borisov -hereafter 2I -is the first visibly active interstellar comet observed in the solar system, allowing us for the first time to sample the composition of a building block from another system. We report on the monitoring of 2I with the Ultraviolet-Visual Echelle Spectrograph (UVES), the high resolution optical spectrograph of the ESO Very Large Telescope at Paranal, during four months from November 15, 2019 to March 16, 2020. Our goal is to characterize the activity and composition of 2I with respect to solar system comets. Methods. We collected high resolution spectra at 12 different epochs from 2.1 au pre-perihelion to 2.6 au post perihelion. Results. On December 24 and 26, 2019, close to perihelion, we detected several OH lines of the 309 nm (0-0) band and derived a water production rate of 2.2 ± 0.2 × 10 26 molecules/s. The three [OI] forbidden oxygen lines were detected at different epochs and we derive a green-to-red doublet intensity ratio (G/R) of 0.31 ± 0.05 close to perihelion. NH 2 ortho and para lines from various bands were measured and allowed us to derive an ortho-to-para ratio (OPR) of 3.21 ± 0.15, corresponding to an OPR and spin temperature of ammonia of 1.11 ± 0.08 and 31 +10 −5 K, respectively. These values are consistent with the values usually measured for solar system comets. Emission lines of the radicals NH (336 nm), CN (388 nm), CH (431 nm), and C 2 (517 nm) were also detected. Several FeI and NiI lines were identified and their intensities were measured to provide a ratio of log (NiI/FeI) = 0.21 ± 0.18 in agreement with the value recently found in solar system comets. Conclusions. Our high spectral resolution observations of 2I/Borisov and the associated measurements of the NH 2 OPR and the Ni/Fe abundance ratio are remarkably similar to solar system comets. Only the G/R ratio is unusually high but consistent with the high abundance ratio of CO/H 2 O found by other investigators.

show abstract

Activity of the first interstellar comet 2I/Borisov around perihelion: results from Indian observatories

Cited by 16 publications

References 45 publications

The similarity of the interstellar comet 2I/Borisov to Solar System comets from high-resolution optical spectroscopy

The similarity of the interstellar comet 2I/Borisov to Solar System comets from high-resolution optical spectroscopy

The Population of Interstellar Objects Detectable with the LSST and Accessible for $\textit{In Situ}$ Rendezvous with Various Mission Designs

The similarity of the interstellar comet 2I/Borisov to solar system comets from high resolution optical spectroscopy

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