Image of the Week

 

Meet your neighbours: CNS5 - the fifth catalogue of nearby stars

 

Figure 1. Colour-magnitude diagram (CMD) for all CNS5 objects in both Gaia EDR3 and WISE photometric bands. The main plot shows the G − RP colours of Gaia EDR3 objects, including those with synthetic colours, as well as objects from HIPPARCOS that do not have a counterpart in Gaia EDR3, with converted G and RP magnitudes. The top and right axes indicate the spectral type, and the blue cross represents the position of the Sun on the CMD. The grey shaded area corresponds to the region where the number of main-sequence objects not present in Gaia starts to increase. This region is represented in an inset plot in WISE bands, with the spectral type denoted on the top axis. Colour represents the density of star counts per pixel. Credits: Golovin et al. A&A 2023

 

The recently published CNS5 catalogue (The Fifth Catalogue of Nearby Stars) is an update to the Gliese-Jahreiß Catalogue of Nearby Stars and contains all known objects located within 25 parsecs (about 81.5 light-years) of the Sun.

The CNS5 contains in total 5931 objects, including 5230 stars and 701 brown dwarfs. Of the stars, 4946 are main-sequence stars (stars that are still burning hydrogen in their cores), 20 are red giants (stars that have exhausted their supply of hydrogen and are expanding), and 264 are white dwarfs (remnants of dead stars that have exhausted their fuel and are cooling off), see Figure 1. An update was indeed required, as the most recent publicly available version of the catalogue of nearby stars was published more than 30 years ago and was entitled the Preliminary Version of the Third Catalogue of Nearby Stars (Gliese &Jahreiß 1991). The fourth version of the catalogue, CNS4, had been prepared but never published.

The compilation of the CNS5 is much more complicated than just selecting all sources with parallaxes larger than 40 mas which corresponds to a maximum distance of 25 pc or 81.5 light-years, respectively. The reasons include a number of issues: i) spurious catalogue entries with apparently large parallaxes, which have to be filtered out; ii) blended sources whose photometry has to be deblended before they can be reliably placed into a Hertzsprung-Russell diagram; and iii) cross-matching of binary and multiple stars can be a difficult task too, as the position on the sky of their components is constantly changing due to the orbital motion. In addition, quite often reliable parallaxes are not available for all of the components and different catalogues may use different approaches to identify binary and multiple stars, which can lead to differences in the number and characteristics of these systems listed in each catalogue.

While the majority of the objects (87%) in the Fifth Catalogue of Nearby Stars are coming from Gaia EDR3, a variety of catalogues and surveys is needed to construct a truly complete catalogue. The Gaia EDR3 catalogue does not contain the brightest stars, thus information from the Hipparcos Catalogue for these brighter stars was added. To complement for optically faint objects, like brown dwarfs, information from ground-based infrared parallax surveys (Best et al. 2021; Kirkpatrick et al. 2021) was added as well.

 

Figure 2. The blue solid line separates the sources into two groups: sources located above the line have astrometric solutions that are considered spurious, while those located below the line have solutions that are considered to be reliable astrometric solutions in Gaia EDR3. 692 sources, or 11.78% of the total, fall into the spurious category and are located above the threshold defined by the blue line. These spurious sources were removed and are no longer part of the CNS5. Credits: Golovin et al. A&A 2023

 

To select only sources with reliable parallaxes from Gaia EDR3, the authors applied a simple yet powerful cut (See Figure 2) on the amplitude of the Image Parameter Determination goodness-of-fit (IPD GoF; ipd_gof_harmonic_amplitude in Gaia EDR3). This parameter can be regarded as a proxy for the asymmetry of the image, and sources with a large IPD GoF amplitude and a low parallax-over-error ratio turned out to be spurious. A simple RUWE cut, which has been often used before, is prone to magnitude-dependent biases and could be shown to be not optimal for constructing a catalogue where not only completeness but also cleanliness is important.

In addition, CNS5 provides synthetic (or deblended) G-RP for objects with photometry in Gaia EDR3 with a sufficiently large signal-to-noise ratio. These are derived from the model fit to the Gaia photometry for a carefully selected sample of objects with high-quality BP and RP photometry. Using original G-RP colours (as published in Gaia EDR3) for objects affected by blending or contamination would yield a Hertzsprung-Russell diagram where these objects appear redder than expected and do not fall on the main-sequence or white dwarf sequence where one would expect them, as illustrated in Figure 3. This issue affects primarily BP and RP fluxes (but not their ratios!) because the CCD windows there are much larger than those of the astrometric field from which the G flux is derived. Thus, the blending correction to the G-RP colour can be derived based on the BP and RP fluxes. This method is applicable not only to nearby stars but can be useful for a number of other science cases.

 

Figure 3. Difference between the measured and deblended G − RP colours for objects in the CNS5 that have a counterpart in Gaia EDR3 and their location on the Colour Magnitude Diagram (CMD). Top: CMD using the measured G − RP colour (as published in Gaia EDR3). Bottom: CMD for the same sample, but using synthetic (deblended) G − RP colours from the CNS5. The colour bar indicates the absolute difference between the measured and synthetic G − RP colours. The stars colour-coded in red are the ones with the largest differences between the two colours. Only objects with BP − RP colours within the applicability range 0.0 mag < BP − RP < 4.25 mag are plotted. The colour scale is logarithmic. The two CMDs illustrate the impact of deblending on the colours and positions of the stars in the CMD. Credits: Golovin et al. A&A 2023

 

As opposed to the Gaia Catalogue of Nearby Stars (GCNS), which lists all stars within 100 pc, the CNS5 adheres to its traditional volume of 25 pc around the Sun. In order to make statistical analyses based on the volume-limited sample as a whole easier, it strives for completeness and purity in the final census of nearby stars to the greatest extent possible. Naturally, completeness is higher in the CNS5 than in the GCNS, but this comes at the expense of a smaller volume. The applications of the two catalogues are thus to some extent complementary.

Stars in the solar neighbourhood help us to understand better the more remote parts of our Galaxy. Also, solar neighbourhood stars are of great importance, as only there we can detect the majority of brown dwarfs and white dwarfs. Detecting such faint and compact objects at larger distances is so challenging that many of them are yet to be discovered. Furthermore, nearby stars are frequently used to develop concepts that are then applied elsewhere in the universe. Thus, the CNS5 catalogue can be used for a broad range of applications, including estimating the number of stars in the Galaxy and modelling the Galactic disc, the present-day and initial mass functions, the stellar luminosity function and its fine structure, constraints on star formation, the local stellar number density, stellar multiplicity, brown dwarfs, and exoplanet target lists.

The next version of the catalogue, CNS6, is already in preparation, and it will be focused on providing more information about multiplicity as well as astrophysical parameters for all stars in the CNS.

 

Animation: This is a visualisation of the updated Catalogue of Nearby Stars 5 (CNS5), featuring stellar systems located within a distance of 25 parsecs or 81.5 light-years from the Sun. It is based on the paper "The Fifth Catalogue of Nearby Stars (CNS5)" by Alex Golovin et al. (A&A 2023). The animation was created using Gaia Sky and begins with a flyover view of the Milky Way galaxy before transitioning to a close-up of the stars listed in the CNS5. It also illustrates the movement of these stars as measured by the Gaia and Hipparcos space telescopes, and some ground observatories. The region within 25 parsecs of the Sun, known as the immediate solar neighbourhood, is a unique and diverse mixture of stellar populations. It has served as a testbed for various concepts and theories, which can be applied and extended to other regions of our Galaxy that are more difficult to observe directly. Credits: The video was created by Stefan Jordan with Gaia Sky, developed by Toni Sagristà at the Astronomisches Rechen-Institut, University of Heidelberg, Germany. Narrator voice produced with the free text-to-speech converter https://ttsmp3.com. CC BY-SA 3.0 IGO

 

Further reading:

The Fifth Catalogue of Nearby Stars (CNS5) by Golovin et al. A&A (2023)

 

 

Credits: Story written by Golovin et al.

[Published: 25/01/2023]

Image of the Week Archive

2023

31/01: Gaia reaches to the clouds – 3D kinematics of the LMC

25/01: Meet your neighbours: CNS5 - the fifth catalogue of nearby stars

18/01: A single-object visualisation tool for Gaia objects

2022

25/11: 100 months of Gaia data

23/11: The astonishment

09/11: Gamma-Ray Burst detection from Lagrange 2 point by Gaia

04/11: Gaia's first black hole discovery: Gaia BH1

26/10: Are Newton and Einstein in error after all?

21/10: Gaia ESA Archive goes live with third data release

06/10: Mapping the interstellar medium using the Gaia RVS spectra

26/09: Gaia on the hunt for dual quasars and gravitational lenses

23/09: Gaia's observation of relativistic deflection of light close to Jupiter

13/06: Gaia Data Release 3

10/06: MK classification of stars from BP/RP spectrophotometry across the Hertzsprung-Russell diagram

09/06: BP/RP low-resolution spectroscopy across the Hertzsprung-Russell diagram

27/05: Cepheids and their radial velocity curves

23/05: The Galaxy in your preferred colours

19/05: GaiaXPy 1.0.0 released, a tool for Gaia's BP/RP spectra users

11/05: Systemic proper motions of 73 galaxies in the Local group

28/03: Gaia query statistics

16/03: Gaia's first photo shooting of the James Webb Space Telescope

08/03: Gaia's women in science - coordination unit 8

25/02: Not only distances: what Gaia DR3 RR Lyrae stars will tell us about our Galaxy and beyond

11/02: Gaia's women in science

31/01: Astrometric orbit of the exoplanet-host star HD81040

12/01: The Local Bubble - source of our nearby stars

05/01: A Milky-Way relic of the formation of the Universe

2021

23/12: Signal-to-Noise ratio for Gaia DR3 BP/RP mean spectra

22/12: The 7 October 2021 stellar occultation by the Neptunian system

01/12: Observation of a long-predicted new type of binary star

24/09: Astrometric microlensing effect in the Gaia16aye event

22/09: the power of the third dimension - the discovery of a gigantic cavity in space

16/09: An alternative Gaia sky chart

25/08: Gaia Photometric Science Alerts and Gravitational Wave Triggers

09/07: How Gaia unveils what stars are made of

23/06: Interviews with CU3

27/04: HIP 70674 Orbital solution resulting from Gaia DR3 processing

30/03: First transiting exoplanet by Gaia

26/03: Apophis' Yarkovsky acceleration improved through stellar occultation

26/02: Matching observations to sources for Gaia DR4

2020

22/12: QSO emission lines in low-resolution BP/RP spectra

03/12: Gaia Early Data Release 3

29/10: Gaia EDR3 passbands

15/10: Star clusters are only the tip of the iceberg

04/09: Discovery of a year long superoutburst in a white dwarf binary

12/08: First calibrated XP spectra

22/07: Gaia and the size of the Solar System

16/07: Testing CDM and geometry-driven Milky Way rotation Curve Models

30/06: Gaia's impact on Solar system science

14/05: Machine-learning techniques reveal hundreds of open clusters in Gaia data

20/03: The chemical trace of Galactic stellar populations as seen by Gaia

09/01: Discovery of a new star cluster: Price-Whelan1

08/01: Largest ever seen gaseous structure in our Galaxy

2019
20/12: The lost stars of the Hyades
06/12: Do we see a dark-matter like effect in globular clusters?
12/11: Hypervelocity star ejected from a supermassive black hole
17/09: Instrument Development Award
08/08: 30th anniversary of Hipparcos
17/07: Whitehead Eclipse Avoidance Manoeuvre
28/06: Following up on Gaia Solar System Objects
19/06: News from the Gaia Archive
29/05: Spectroscopic variability of emission lines stars with Gaia
24/05: Evidence of new magnetic transitions in late-type stars
03/05: Atmospheric dynamics of AGB stars revealed by Gaia
25/04: Geographic contributions to DPAC
22/04: omega Centauri's lost stars
18/04: 53rd ESLAB symposium "the Gaia universe"
18/02: A river of stars
2018
21/12: Sonification of Gaia data
18/12: Gaia captures a rare FU Ori outburst
12/12: Changes in the DPAC Executive
26/11:New Very Low Mass dwarfs in Gaia data
19/11: Hypervelocity White Dwarfs in Gaia data
15/11: Hunting evolved carbon stars with Gaia RP spectra
13/11: Gaia catches the movement of the tiny galaxies surrounding the Milky Way
06/11: Secrets of the "wild duck" cluster revealed
12/10: 25 years since the initial GAIA proposal
09/10: 3rd Gaia DPAC Consortium Meeting
30/09: A new panoramic sky map of the Milky Way's Stellar Streams
25/09: Plausible home stars for interstellar object 'Oumuamua
11/09: Impressions from the IAU General Assembly
30/06: Asteroids in Gaia Data
14/06: Mapping and visualising Gaia DR2

25/04: In-depth stories on Gaia DR2

14/04: Gaia tops one trillion observations
16/03: Gaia DR2 Passbands
27/02: Triton observation campaign
11/02: Gaia Women In Science
29/01: Following-up on Gaia
2017
19/12: 4th launch anniversary
24/11: Gaia-GOSA service
27/10: German Gaia stamp in the making
19/10: Hertzsprung-russell diagram using Gaia DR1
05/10: Updated prediction to the Triton occultation campaign
04/10: 1:1 Gaia model arrives at ESAC
31/08: Close stellar encounters from the first Gaia data release
16/08: Preliminary view of the Gaia sky in colour
07/07: Chariklo stellar occultation follow-up
24/04: Gaia reveals the composition of asteroids
20/04: Extra-galactic observations with Gaia
10/04: How faint are the faintest Gaia stars?
24/03: Pulsating stars to study Galactic structures
09/02: Known exoplanetary transits in Gaia data
31/01: Successful second DPAC Consortium Meeting
2016
23/12: Interactive and statistical visualisation of Gaia DR1 with vaex
16/12: Standard uncertainties for the photometric data (in GDR1)
25/11: Signature of the rotation of the galactic bar uncovered
15/11: Successful first DR1 Workshop
27/10: Microlensing Follow-Up
21/10: Asteroid Occultation
16/09: First DR1 results
14/09: Pluto Stellar Occultation
15/06: Happy Birthday, DPAC!
10/06: 1000th run of the Initial Data Treatment system
04/05: Complementing Gaia observations of the densest sky regions
22/04: A window to Gaia - the focal plane
05/04: Hipparcos interactive data access tool
24/03: Gaia spots a sunspot
29/02: Gaia sees exploding stars next door
11/02: A new heart for the Gaia Object Generator
04/02: Searching for solar siblings with Gaia
28/01: Globular cluster colour-magnitude diagrams
21/01: Gaia resolving power estimated with Pluto and Charon
12/01: 100th First-Look Weekly Report
06/01: Gaia intersects a Perseid meteoroid
2015
18/12: Tales of two clusters retold by Gaia
11/11: Lunar transit temperature plots
06/11: Gaia's sensors scan a lunar transit
03/11: Celebrity comet spotted among Gaia's stars
09/10: The SB2 stars as seen by Gaia's RVS
02/10: The colour of Gaia's eyes
24/09: Estimating distances from parallaxes
18/09: Gaia orbit reconstruction
31/07: Asteroids all around
17/07: Gaia satellite and amateur astronomers spot one in a billion star
03/07: Counting stars with Gaia
01/07: Avionics Model test bench arrives at ESOC
28/05: Short period/faint magnitude Cepheids in the Large Magellanic Cloud
19/05: Visualising Gaia Photometric Science Alerts
09/04: Gaia honours Einstein by observing his cross
02/04: 1 April - First Look Scientists play practical joke
05/03: RR Lyrae stars in the Large Magellanic Cloud as seen by Gaia
26/02: First Gaia BP/RP deblended spectra
19/02: 13 months of GBOT Gaia observations
12/02: Added Value Interface Portal for Gaia
04/02: Gaia's potential for the discovery of circumbinary planets
26/01: DIBs in three hot stars as seen by Gaia's RVS
15/01: The Tycho-Gaia Astrometric Solution
06/01: Close encounters of the stellar kind
2014
12/12: Gaia detects microlensing event
05/12: Cat's Eye Nebula as seen by Gaia
01/12: BFOSC observation of Gaia at L2
24/11: Gaia spectra of six stars
13/11: Omega Centauri as seen by Gaia
02/10: RVS Data Processing
12/09: Gaia discovers first supernova
04/08: Gaia flag arrives at ESAC
29/07: Gaia handover
15/07: Eclipsing binaries
03/07: Asteroids at the "photo finish"
19/06: Calibration image III - Messier 51
05/06: First Gaia BP/RP and RVS spectra
02/06: Sky coverage of Gaia during commissioning
03/04: Gaia source detection
21/02: Sky-background false detections in the sky mapper
14/02: Gaia calibration images II
06/02: Gaia calibration image I
28/01: Gaia telescope light path
17/01: First star shines for Gaia
14/01: Radiation Campaign #4
06/01: Asteroid detection by Gaia
2013
17/12: Gaia in the gantry
12/12: The sky in G magnitude
05/12: Pre-launch release of spectrophotometric standard stars
28/11: From one to one billion pixels
21/11: The Hipparcos all-sky map
15/10: Gaia Sunshield Deployment Test
08/10: Initial Gaia Source List
17/09: CU1 Operations Workshop
11/09: Apsis
26/08: Gaia arrival in French Guiana
20/08: Gaia cartoons
11/07: Model Soyuz Fregat video
01/07: Acoustic Testing
21/06: SOVT
03/06: CU4 meeting #15
04/04: DPCC (CNES) 
26/03: Gaia artist impression 
11/02: Gaia payload testing  
04/01: Space flyby with Gaia-like data
2012
10/12: DPAC OR#2. Testing with Planck
05/11: Galaxy detection with Gaia
09/10: Plot of part of the GUMS-10 catalogue
23/07: "Gaia" meets at Gaia
29/06: The Sky as seen by Gaia
31/05: Panorama of BAM clean room
29/03: GREAT school results
12/03: Scanning-law movie
21/02: Astrometric microlensing and Gaia
03/02: BAM with PMTS
12/01: FPA with all the CCDs and WFSs
2011
14/12: Deployable sunshield
10/11: Earth Trojan search
21/10: First Soyuz liftoff from the French Guiana
20/09: Fast 2D image reconstruction algorithm
05/09: RVS OMA
10/08: 3D distribution of the Gaia catalogue
13/07: Dynamical Attitude Model
22/06: Gaia's view of open clusters
27/05: Accuracy of the stellar transverse velocity
13/05: Vibration test of BAM mirrors
18/04: L. Lindegren, Dr. Honoris Causa of the Observatory of Paris
19/01: Detectability of stars close to Jupiter
05/01: Delivery of the WFS flight models
2010
21/12: The 100th member of CU3
17/11: Nano-JASMINE and AGIS
27/10: Eclipsing binary light curves fitted with DPAC code
13/10: Gaia broad band photometry
28/09: Measuring stellar parameters and interstellar extinction
14/09: M1 mirror
27/08: Quest for the Sun's siblings
 
Please note: Entries from the period 2003-2010 are available in this PDF document.