Friday, March 23, 2018

Bright Transient in Carina

Following the posting on the ATel #11454 about the discovery by All Sky Automated Survey for SuperNovae survey (ASAS-SN) of a new transient source, possibly a classical nova, near the Galactic plane in Carina (ASAS-SN Designation: ASASSN-18fv) I performed some follow-up of this object through a 0.43-m f/6.8 astrograph + CCD from MPC Code Q62 (iTelescope Observatory, Siding Spring).

On images taken on March 23.4, 2018 I can confirm the presence of an optical counterpart with R-filtered CCD magnitude +5.7 at coordinates:

R.A. = 10 36 15.42, Decl.= -59 35 53.7

(equinox 2000.0; UCAC-4 catalogue reference stars).

Below you can see my confirmation image (single 20-sec exposure through a 0.43-m f/6.8 astrograph + CCD), click on it for a bigger version:

While below you can see a wide-field color image (90 second exposures) I obtained on March 23.4, 2018 through a Takahashi SKY90 Apochromatic Refractor f5/6 + Color CCD. In the image ASASSN-18fv is visible at the centre of the field together with part of the Carina Nebula (click on it for a bigger version):

This transient was discovered using data from the quadruple 14-cm "Cassius" telescope in CTIO, Chile of ASAS-SN survey on images obtained on UT 2018-03-20.32 at V<10 2018-03-16.32="" also="" asas-sn="" asassn-18fv="" at="" detected="" detection="" no="" on="" possibly="" saturated="" starting="" ut="" v="">17.0) of this object in subtracted images taken on UT 2018-03-15.34 and before by the same survey. No previous outbursts or variability are detected at the position of ASASSN-18fv since ASAS-SN started observing this location in February 2016. 

According to Atel #11467 pre-discovery images have been identified on images obtained by Evryscope-South, an array of 6-cm telescopes continuously monitoring 8000 square degrees of sky at 2-minute cadence from CTIO, Chile. The transient is not detected at UT 2018-03-16.0316 with an upper-limit of 11.9 +/- 0.1 mag (g'). Beginning at UT 2018-03-16.227, they detected a new source at 10.21 +/- 0.05 mag (g'). (click on the images below for a bigger version).

Credit: Evryscope
Credit: Evryscope

An animation showing a comparison between my confirmation image and the archive POSS2/UKSTU Red plate (1991-02-10). Click on it for a bigger version:

Spectroscopy by  P. Luckas (see ATel #11460) seems to indicate that ASASSN-18fv is a classical nova brightening and in the optically thick (Fe curtain) phase. 

But according to L. Izzo et al. (ATel #11468): "The lack of a strong blue continuum, that is however typical of classical nova outburst, and the low expansion velocities suggest a possible different nature for this object. The presence of many narrow absorptions also suggests a similarity with other peculiar explosions, like the luminous red variable V4332 Sgr (Martini et al. 1999), the possible luminous red novae V838 Mon and V1309 Sco (Tylenda et al. 2011, Mason et al. 2010) or the 'helium-flash' explosion observed in the Sakurai object (Duerbeck and Benetti 1996)". Doubts about the nova nature of this object were expressed also by J. Strader et al. (ATel #11456)

So further spectroscopic observations are important to clarify the nature of this very interesting transient.

by Ernesto Guido

Monday, March 19, 2018

New Comet: C/2018 E1 (ATLAS)

CBET nr. 4494, issued on 2018, March 16, announces the discovery of an apparently asteroidal object (magnitude ~17) in the course of the "Asteroid Terrestrial-impact Last Alert System" (ATLAS) search program on CCD images obtained with a 0.5-m f/2 Schmidt reflector at Haleakala, Hawaii. Posted on the Minor Planet Center's PCCP webpage, it has been reported as showing cometary activity by CCD astrometrists elsewhere. The new comet has been designated C/2018 E1 (ATLAS). 

I performed follow-up measurements of this object, while it was still on the PCCP webpage. Stacking of 5 unfiltered exposures, 60 seconds each, obtained remotely on 2018, March 12.4 from Q62 (iTelescope network) through a 0.70-m f/6.6 reflector + CCD, shows that this object is a comet with a diffuse coma about 5 arcsec in diameter. The FWHM of this object was measured about 20% wider than that of nearby field stars of similar brightness.

My confirmation image (click on it for a bigger version)

"Pre-discovery" Panstarrs observations (2015 & 2016) were identified by R. Weryk. M.P.E.C. 2018-F10 assigns the following elliptical orbital elements to comet C/2018 E1: T 2018 Apr. 17.3; e= 0.95; Peri. =  299.47; q = 2.70;  Incl.= 72.48

by Ernesto Guido

Friday, February 9, 2018

Image & Animation of "2018-017A" a.k.a. #Starman

On February 06, 2018 at 20:45 UT, SpaceX successfully launched the Falcon Heavy, a reusable super heavy-lift launch vehicle, introduced as the most powerful rocket currently in operation.

The dummy payload for this test flight was a sports car owned by SpaceX CEO Elon Musk, a midnight cherry, first generation Tesla Roadster. It was selected as "something fun and without irreplaceable sentimental value" to be launched into space on the maiden flight of the Falcon Heavy rocket. The purpose of including the Roadster on the maiden flight was to demonstrate that the Falcon Heavy can launch payloads as far as the orbit of Mars.

Sitting in the driver's seat of the Roadster is "Starman", a dummy astronaut clad in a SpaceX spacesuit. He has his right hand on the steering wheel and left elbow resting on the open window sill. Starman is named for the David Bowie song "Starman". The car's sound system was looping the symbolic Bowie songs "Space Oddity" and "Life on Mars?". A copy of Douglas Adams' 1979 novel "The Hitchhiker's Guide to the Galaxy" is in the glovebox, along with a towel and a sign on the dashboard that reads "Don't Panic!" (two references to the book).

Credit: Spacex

On February 09.4, 2018 I performed follow-up of the #Starman #TeslaRoadster (officially designated 2018-017A) remotely from MPC code H06 (Mayhill, New Mexico; iTelescope network) through a 0.25-m f/3.4 reflector + CCD. Click on the image below for a bigger version.

While below you can see a short animation showing the motion of Starman in about 20 minutes. Each frame is a 60-second exposure. North is up, East to the left.

In the hours after the successful Falcon Heavy launch, a live video feed of the Roadster and Starman from three cameras mounted inside and on booms attached to the outside of the vehicle was broadcast on YouTube. It was expected to last for about twelve hours until the on-board batteries were depleted; however, the livestream lasted for just over four hours. Full video stream of the car as it creates spectacular views of Earth from space is still available, see Youtube video below.

By Ernesto Guido

Thursday, February 8, 2018

Comets & Asteroids - Summary Aug through Dec 2017

During the 5-month period Aug through Dec 2017, 22 new comets were discovered, cometary activity was detected for 5 previously discovered object (earlier designated as an asteroid) and there were 5 comet  recoveries. "Current comet magnitudes" & "Daily updated asteroid flybys" pages are available at the top of this blog (or just click on the underline text here). See below for the "Other news" section. 

The dates below refer to the date of issuance of CBET (Central Bureau Electronic Telegram)  which reported the official news & designations.

- Comet Discoveries

Aug 17 Discovery of P/2017 P1 (PANSTARRS)
Aug 23 Discovery of C/2017 P2 (PANSTARRS)

Sep 22 Discovery of P/2017 R1 (PANSTARRS)
Sep 22 Discovery of C/2017 S2 (PANSTARRS)
Sep 27 Discovery of C/2017 S3 (PANSTARRS)
Sep 29 Discovery of P/2017 S5 (ATLAS)

Comet P/2017 S5 - Credit: ATLAS survey

Oct 08 Discovery of C/2017 S6 (CATALINA)
Oct 08 Discovery of C/2017 S7 (LEMMON)
Oct 16 Discovery of C/2017 T1 (HEINZE)
Oct 25 Discovery of C/2017 T2 (PANSTARRS)
Oct 28 Discovery of P/2017 S8 (PANSTARRS)
Oct 28 Discovery of P/2017 S9 (PANSTARRS)
Oct 28 Discovery of C/2017 T3 (ATLAS)
Oct 29 Discovery of C/2017 U2 (FULS)

Nov 13 Discovery of P/2017 U3 (PANSTARRS)
Nov 20 Discovery of C/2017 U4 (PANSTARRS)

Dec 03 Discovery of C/2017 U5 (PANSTARRS)
Dec 19 Discovery of C/2017 W2 (LEONARD)
Dec 19 Discovery of P/2017 W3 (GIBBS)
Dec 19 Discovery of C/2017 X1 (PANSTARRS)
Dec 31 Discovery of C/2017 Y1 (PANSTARRS)
Dec 31 Discovery of C/2017 Y2 (PANSTARRS)

- Cometary activity detected

Aug 03 Following the announcement on CBET 4415 of the possible connection of 2017 MB_1 and the alpha Cap meteor shower, P. Birtwhistle, Great Shefford, Berkshire, England, re-examined his CCD images of 2017 MB_1 taken using a 0.40-m Schmidt-Cassegrain reflector on several dates. There are no traces of cometary activity on co-added exposures taken on July 4.04 (10 min exposure time) and 5.04 UT (30 min total exposure), but on July 25.11, stacked exposures totalling 7.2 min show a possible very faint, thin, straight tail in p.a. 260 deg, appearing detached from the main object, starting at a distance of 35" and extending to 90" from 2017 MB_1. The images from July 25 were taken in brightening nautical twilight (solar altitude -12.8 to -12.0 degrees), but he is reasonably confident that the possible tail is real and not an artifact.

Aug 11 Cometary activity detected in the NEOWISE images containing minor planet 2014 XK_6

Aug 25 Cometary activity detected in 2007 RS_41 = P/2017 Q2 (LONEOS)

Sep 28 Cometary activity detected in 2006 UR_111 (SPACEWATCH) = P/2017 S4

Dec 13 Cometary activity detected in 2000 XO_8

- Comet Recoveries

Aug 03  Recovery of P/2010 D1 (WISE) as P/2017 O2
Aug 22  Recovery of P/2008 T4 (HILL) as P/2017 Q1
Aug 26  Recovery of P/2012 T1 (PANSTARRS) as P/2017 O3
Sep 20  Recovery of P/2010 P4 (WISE) as P/2017 S1
Nov 20  Recovery of P/2011 VJ_5 (LEMMON) as P/2017 W1

Oct 09 CBET 4442 reports that the following name has been voted upon by the IAU Working Group on Small Body Nomenclature for a recently discovered comet:

Designation (Name)                     Discovery Reference
351P/Wiegert-PANSTARRS             CBET 4439*
C/2017 O1 (ASASSN)                     CBET 4414

* Further to CBET 4298, G. V. Williams (Minor Planet Center) has linked a reported comet from 2007 to comet P/2016 P2. The comet has been given the permanent number 351P and year designations P/2016 P2 = P/1998 U8 = P/2007 R11.

Further to CBETs 4376 and 4439, the following permanent numbers have been assigned to short-period comets based upon their being securely observed at multiple returns to perihelion.

Designation/Name         Provisional Designations                 Reference
352P/Skiff                     P/2000 S1 = P/2017 L1                    CBET 4402
353P/McNaught            P/2009 S2 = P/2017 M1                   CBET 4404
354P/LINEAR              P/2010 A2 = P/2017 B5                    CBET 4405
355P/LINEAR-NEAT     P/2004 T1 = P/2017 M2                   CBET 4406
356P/WISE                   P/2010 D1 = P/2017 O2                    CBET 4441
357P/Hill                       P/2008 T4 = P/2017 Q1                    CBET 4422
358P/PANSTARRS       P/2012 T1 = P/2017 O3                    CBET 4425
359P/LONEOS              P/2007 RS_41 = P/2017 Q2             CBET 4424
360P/WISE                    P/2010 P4 = P/2017 S1                    CBET 4429
361P/Spacewatch          P/2006 UR_111 = P/2017 S4            CBET 4433
362P/(457175)              P/2008 GO_98                                   CBET 4411

- Other news

Aug 06 Asteroid 2012 TC4 has been recovered. Close approach on Oct. 12 at ~50200 km. Images from 2012 available here while images & animation of Oct. 2017 close approach are available here.

Aug 17 New paper on Arxiv by Jian-Yang Li et al. : "The Unusual Apparition of Comet 252P/2000 G1 (LINEAR) and Comparison with Comet P/2016 BA14 (PanSTARRS)"

Sep 01 Goldstone Radar Images of asteroid (3122) Florence. Florence will approach  within 0.047 AU on 2017 September 1 (FOTO). Radar Reveals Two Moons Orbiting Asteroid Florence.

Credit: Goldstone

Sep 16 New paper on Arxiv by Snodgrass et al. : "The Main Belt Comets and Ice in the Solar System"

Sep 20 NASA’s Hubble Space Telescope helped an international team of astronomers find that an unusual object in the asteroid belt is, in fact, two asteroids orbiting  each other that have comet-like features. These include a bright halo of material,  called a coma, and a long tail of dust. The time-lapse video below, assembled from a set of Hubble Space Telescope photos, reveals two asteroids orbiting each other that have comet-like features. The asteroid pair, called 2006 VW139/288P, was observed in September 2016, just before the asteroid made its closest approach to the Sun.

Credits: NASA, ESA, and J. DePasquale and Z. Levay (STScI)

Sep 29 NASA's Hubble Observes the Farthest Active Inbound Comet Yet Seen  - Paper by Jewitt et al. available here.

Credits: NASA, ESA, and D. Jewitt (UCLA)

Oct 04 CBET 4435, CBET 4436, CBET 4440 (Oct.09) & CBET 4459 (Dec. 08) report that the following minor planets are binaries systems: 2017 RV1; (23621) 1996 PA; (10132) LUMMELUNDA; (3378) SUSANVICTORIA

Oct 11 New paper on Arxiv by Meech et al: "CO-Driven Activity in Comet C/2017 K2 (PANSTARRS)"

Oct 25 The first clear case of an interstellar object A/2017 U1. According to CBET 4450 "inadvertently designated as comet C/2017 U1 on MPEC 2017-U181 (and changed to A/2017 U1) with no claimed cometary appearance by anyobservers appears to have hyperbolic orbital elements". A/2017 U1 was discovered Oct. 19 by the University of Hawaii's Pan-STARRS 1 telescope on Haleakala during the course of its nightly search for Near-Earth Objects for NASA. appears to have originated from outside the solar system, coming from somewhere else in our galaxy. If so, it would be the first "interstellar object" to be observed and confirmed by astronomers. According to MPEC 2017-V17: "the object A/2017 U1 receives the permanent designation 1I and the name ʻOumuamua.  The name, which was chosen by the Pan-STARRS team, is of Hawaiian origin and reflects the way this object is like a scout or messenger sent from the distant past to reach out to us (ʻou means reach out for, and mua, with the second mua placing emphasis, means first, in advance of). Correct forms for referring to this object are therefore: 1I; 1I/2017 U1; 1I/ʻOumuamua; and 1I/2017 U1 (ʻOumuamua).

Oct 27 Comet 96P/Machholz in the LASCO C3 camera on ESA/NASA SOHO.

Credit: SOHO

Dec 08 New Outburst of 174P/Echeclus


Dec 22 Radar images of asteroid (3200) Phaethon via Arecibo Radar

by Ernesto Guido

Saturday, January 20, 2018

Possible Nova in Circinus

Following the posting on the Central Bureau's Transient Object Confirmation Page about a possible Nova in Circinus (TOCP Designation: PNV J13532700-6725110) I performed some follow-up of this object through a TEL 0.43-m f/6.8 reflector + CCD from MPC Code Q62 (iTelescope Observatory, Siding Spring). 

On images taken on January 20.6, 2018 I can confirm the presence of an optical counterpart with R-filtered CCD magnitude +8.09 & V-filtered CCD magnitude +8.33 at coordinates: 

R.A. = 13 53 27.57, Decl.= -67 25 01.0 

(equinox 2000.0; Gaia DR1 catalogue reference stars for the astrometry).

This transient has been reported to CBAT/TOCP by John Seach, Chatsworth Island, NSW, Australia. Discovery made with a DSLR with 50 mm f/1.2 lens.

Below my confirmation image (single unfiltered 60-sec exposure through a 0.43-m f/6.8 reflector + CCD; MPC Code Q62). Click on the image for a bigger version: 

An animation showing a comparison between the confirmation image and the archive POSS2/UKSTU Red plate (1997-03-31). Click on the animation for a bigger version: 

UPDATE - January 31, 2018

According to CBET 4482 issued on January 30, Spectroscopy by Strader et al., obtained with the 4.1-m Southern Astrophysical Research Telscope (+ Goodman spectrograph) at Cerro Pachon, Chile, on Jan. 21.28 UT shows clear P-Cyg profiles in the Balmer lines, with the absorption troughs located about 1300 km/s blueward of the rest wavelength (emission FWHM about 1500 km/s), and a number of Fe II lines (some of which also have P-Cyg profiles) -- suggestive of a "Fe II"-type nova. See also ATel #11209. While a low-resolution spectroscopic image by S. Kiyota that shows a strong hydrogen emission line is available here.

This nova has been designated NOVA CIRCINI 2018.

by Ernesto Guido

Monday, January 15, 2018

Possible Bright Nova in Musca

Following the posting on the Central Bureau's Transient Object Confirmation Page about a possible Nova in Musca (TOCP Designation: PNV J11261220-6531086) we performed some follow-up of this object through a TEL 0.50-m f/6.8 reflector + CCD + focal reducer from MPC Code Q62 (iTelescope Observatory, Siding Spring).

On images taken on January 15.57, 2018 we can confirm the presence of an optical counterpart with R-filtered CCD magnitude ~6.3 at coordinates:

R.A. = 11 26 14.95, Decl.= -65 31 24.1

(equinox 2000.0; Gaia DR1 catalogue reference stars).

This transient has been reported to CBAT/TOCP by Rob Kaufman, Bright, Victoria, Australia. Discovery image (taken with Canon 650D & 55mm lens) is available here. He also posted a low-resolution spectrum that "shows strong hydrogen emissions as well as FeII lines":

Credit: R. Kaufman

Below you can see our confirmation image (single 30-sec exposure through a 0.43-m f/6.8 reflector + CCD), click on it for a bigger version:

An animation showing a comparison between our confirmation image and the archive POSS2/UKSTU Red plate (1998-03-19). Click on it for a bigger version:

UPDATE - January 16, 2018

According to CBET 4472 this transient could be a classical "Fe II"-type nova and it has been designated NOVA MUSCAE 2018.

by Ernesto Guido & Alfonso Noschese